Commit Graph

145 Commits

Author SHA1 Message Date
Cédric Le Goater
bea3d6e745 spapr/drc: Clean up local variable shadowing in rtas_ibm_configure_connector()
Remove extra 'drc_index' variable to avoid this warning :

  ../hw/ppc/spapr_drc.c: In function ‘rtas_ibm_configure_connector’:
  ../hw/ppc/spapr_drc.c:1240:26: warning: declaration of ‘drc_index’ shadows a previous local [-Wshadow=compatible-local]
   1240 |                 uint32_t drc_index = spapr_drc_index(drc);
        |                          ^~~~~~~~~
  ../hw/ppc/spapr_drc.c:1155:14: note: shadowed declaration is here
   1155 |     uint32_t drc_index;
        |              ^~~~~~~~~

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-ID: <20230918145850.241074-7-clg@kaod.org>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2023-09-29 10:07:18 +02:00
Markus Armbruster
a67dfa660b Drop duplicate #include
Tracked down with the help of scripts/clean-includes.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230202133830.2152150-21-armbru@redhat.com>
2023-02-08 07:28:05 +01:00
Markus Armbruster
047f2ca1ce qapi qdev qom: Elide redundant has_FOO in generated C
The has_FOO for pointer-valued FOO are redundant, except for arrays.
They are also a nuisance to work with.  Recent commit "qapi: Start to
elide redundant has_FOO in generated C" provided the means to elide
them step by step.  This is the step for qapi/qdev.json and
qapi/qom.json.

Said commit explains the transformation in more detail.  The invariant
violations mentioned there do not occur here.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Eduardo Habkost <eduardo@habkost.net>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221104160712.3005652-21-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
2022-12-14 20:05:07 +01:00
Daniel Henrique Barboza
5436eee1ac hw/ppc/spapr_drc.c: use g_autofree in spapr_drc_by_index()
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220228175004.8862-11-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
2022-03-02 06:51:40 +01:00
Daniel Henrique Barboza
7614114e90 hw/ppc/spapr_drc.c: use g_autofree in spapr_dr_connector_new()
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220228175004.8862-10-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
2022-03-02 06:51:39 +01:00
Daniel Henrique Barboza
ef2ece4a87 hw/ppc/spapr_drc.c: use g_autofree in drc_unrealize()
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220228175004.8862-9-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
2022-03-02 06:51:39 +01:00
Daniel Henrique Barboza
37deca77a6 hw/ppc/spapr_drc.c: use g_autofree in drc_realize()
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220228175004.8862-8-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
2022-03-02 06:51:39 +01:00
Daniel Henrique Barboza
75610acfd3 hw/ppc/spapr_drc.c: use g_auto in spapr_dt_drc()
Use g_autoptr() with GArray* and GString* pointers to avoid calling
g_free() and the need for the 'out' label.

'drc_name' can also be g_autofreed to avoid a g_free() call at the end
of the while() loop.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220228175004.8862-7-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
2022-03-02 06:51:39 +01:00
Daniel Henrique Barboza
4b08cd567b spapr: use DEVICE_UNPLUG_GUEST_ERROR to report unplug errors
Linux Kernel 5.12 is now unisolating CPU DRCs in the device_removal
error path, signalling that the hotunplug process wasn't successful.
This allow us to send a DEVICE_UNPLUG_GUEST_ERROR in drc_unisolate_logical()
to signal this error to the management layer.

We also have another error path in spapr_memory_unplug_rollback() for
configured LMB DRCs. Kernels older than 5.13 will not unisolate the LMBs
in the hotunplug error path, but it will reconfigure them. Let's send
the DEVICE_UNPLUG_GUEST_ERROR event in that code path as well to cover the
case of older kernels.

Acked-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210907004755.424931-7-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-09-30 12:26:06 +10:00
Daniel Henrique Barboza
91bd95ce16 spapr_drc.c: do not error_report() when drc->dev->id == NULL
The error_report() call in drc_unisolate_logical() is not considering
that drc->dev->id can be NULL, and the underlying functions error_report()
calls to do its job (vprintf(), g_strdup_printf() ...) has undefined
behavior when trying to handle "%s" with NULL arguments.

Besides, there is no utility into reporting that an unknown device was
rejected by the guest.

Acked-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210907004755.424931-4-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-09-29 19:37:39 +10:00
Peter Maydell
d90f154867 ppc patch queue 2021-05-04
Here's the first ppc pull request for qemu-6.1.  It has a wide variety
 of stuff accumulated during the 6.0 freeze.  Highlights are:
 
  * Multi-phase reset cleanups for PAPR
  * Preliminary cleanups towards allowing !CONFIG_TCG for the ppc target
  * Cleanup of AIL logic and extension to POWER10
  * Further improvements to handling of hot unplug failures on PAPR
  * Allow much larger numbers of CPU on pseries
  * Support for the H_SCM_HEALTH hypercall
  * Add support for the Pegasos II board
  * Substantial cleanup to hflag handling
  * Assorted minor fixes and cleanups
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Merge remote-tracking branch 'remotes/dg-gitlab/tags/ppc-for-6.1-20210504' into staging

ppc patch queue 2021-05-04

Here's the first ppc pull request for qemu-6.1.  It has a wide variety
of stuff accumulated during the 6.0 freeze.  Highlights are:

 * Multi-phase reset cleanups for PAPR
 * Preliminary cleanups towards allowing !CONFIG_TCG for the ppc target
 * Cleanup of AIL logic and extension to POWER10
 * Further improvements to handling of hot unplug failures on PAPR
 * Allow much larger numbers of CPU on pseries
 * Support for the H_SCM_HEALTH hypercall
 * Add support for the Pegasos II board
 * Substantial cleanup to hflag handling
 * Assorted minor fixes and cleanups

# gpg: Signature made Tue 04 May 2021 06:52:39 BST
# gpg:                using RSA key 75F46586AE61A66CC44E87DC6C38CACA20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>" [full]
# gpg:                 aka "David Gibson (Red Hat) <dgibson@redhat.com>" [full]
# gpg:                 aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>" [full]
# gpg:                 aka "David Gibson (kernel.org) <dwg@kernel.org>" [unknown]
# Primary key fingerprint: 75F4 6586 AE61 A66C C44E  87DC 6C38 CACA 20D9 B392

* remotes/dg-gitlab/tags/ppc-for-6.1-20210504: (46 commits)
  hw/ppc/pnv_psi: Use device_cold_reset() instead of device_legacy_reset()
  hw/ppc/spapr_vio: Reset TCE table object with device_cold_reset()
  hw/intc/spapr_xive: Use device_cold_reset() instead of device_legacy_reset()
  target/ppc: removed VSCR from SPR registration
  target/ppc: Reduce the size of ppc_spr_t
  target/ppc: Clean up _spr_register et al
  target/ppc: Add POWER10 exception model
  target/ppc: rework AIL logic in interrupt delivery
  target/ppc: move opcode table logic to translate.c
  target/ppc: code motion from translate_init.c.inc to gdbstub.c
  spapr_drc.c: handle hotunplug errors in drc_unisolate_logical()
  spapr.h: increase FDT_MAX_SIZE
  spapr.c: do not use MachineClass::max_cpus to limit CPUs
  ppc: Rename current DAWR macros and variables
  target/ppc: POWER10 supports scv
  target/ppc: Fix POWER9 radix guest HV interrupt AIL behaviour
  docs/system: ppc: Add documentation for ppce500 machine
  roms/u-boot: Bump ppce500 u-boot to v2021.04 to fix broken pci support
  roms/Makefile: Update ppce500 u-boot build directory name
  ppc/spapr: Add support for implement support for H_SCM_HEALTH
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-05-05 20:29:14 +01:00
Daniel Henrique Barboza
87758fed7a spapr_drc.c: handle hotunplug errors in drc_unisolate_logical()
At this moment, PAPR does not provide a way to report errors during a
device removal operation. This led the pSeries machine to implement
extra mechanisms to try to fallback and recover from an error that might
have happened during the hotunplug in the guest side. This started to
change a bit with commit fe1831eff8 ("spapr_drc.c: use DRC
reconfiguration to cleanup DIMM unplug state"), where one way to
fallback from a memory removal error was introduced.

Around the same time, in [1], the idea of using RTAS set-indicator for
this role was first introduced. The RTAS set-indicator call, when
attempting to UNISOLATE a DRC that is already UNISOLATED or CONFIGURED,
returns RTAS_OK and does nothing else for both QEMU and phyp. This gives
us an opportunity to use this behavior to signal the hypervisor layer
when a device removal errir happens, allowing QEMU/phyp to do a proper
error handling. Using set-indicator to report HP errors isn't strange to
PAPR, as per R1-13.5.3.4-4. of table 13.7 of current PAPR [2]:

"For all DR options: If this is a DR operation that involves the user
insert- ing a DR entity, then if the firmware can determine that the
inserted entity would cause a system disturbance, then the set-indicator
RTAS call must not unisolate the entity and must return an error status
which is unique to the particular error."

A change was proposed to the pSeries Linux kernel to call set-indicator
to move a DRC to 'unisolate' in the case of a hotunplug error in the
guest side [3]. Setting a DRC that is already unisolated or configured to
'unisolate' is a no-op (returns RTAS_OK) for QEMU and also for phyp.
Being a benign change for hypervisors that doesn't care about handling
such errors, we expect the kernel to accept this change at some point.

This patch prepares the pSeries machine for this new kernel feature by
changing drc_unisolate_logical() to handle guest side hotunplug errors.
For CPUs it's a simple matter of setting drc->unplug_requested to 'false',
while for LMBs the process is similar to the rollback that is done in
rtas_ibm_configure_connector().

[1] https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg06395.html
[2] https://openpowerfoundation.org/wp-content/uploads/2020/07/LoPAR-20200611.pdf
[3] https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20210416210216.380291-3-danielhb413@gmail.com/

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210420165100.108368-2-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-05-04 11:41:25 +10:00
Thomas Huth
2068cabd3f Do not include cpu.h if it's not really necessary
Stop including cpu.h in files that don't need it.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210416171314.2074665-4-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-02 17:24:51 +02:00
Daniel Henrique Barboza
d522cb52e6 spapr: rollback 'unplug timeout' for CPU hotunplugs
The pseries machines introduced the concept of 'unplug timeout' for CPU
hotunplugs. The idea was to circunvent a deficiency in the pSeries
specification (PAPR), that currently does not define a proper way for
the hotunplug to fail. If the guest refuses to release the CPU (see [1]
for an example) there is no way for QEMU to detect the failure.

Further discussions about how to send a QAPI event to inform about the
hotunplug timeout [2] exposed problems that weren't predicted back when
the idea was developed. Other QEMU machines don't have any type of
hotunplug timeout mechanism for any device, e.g. ACPI based machines
have a way to make hotunplug errors visible to the hypervisor. This
would make this timeout mechanism exclusive to pSeries, which is not
ideal.

The real problem is that a QAPI event that reports hotunplug timeouts
puts the management layer (namely Libvirt) in a weird spot. We're not
telling that the hotunplug failed, because we can't be 100% sure of
that, and yet we're resetting the unplug state back, preventing any
DEVICE_DEL events to reach out in case the guest decides to release the
device. Libvirt would need to inspect the guest itself to see if the
device was released or not, otherwise the internal domain states will be
inconsistent.  Moreover, Libvirt already has an 'unplug timeout'
concept, and a QEMU side timeout would need to be juggled together with
the existing Libvirt timeout.

All this considered, this solution ended up creating more trouble than
it solved. This patch reverts the 3 commits that introduced the timeout
mechanism for CPU hotplugs in pSeries machines.

This reverts commit 4515a5f786
"qemu_timer.c: add timer_deadline_ms() helper"

This reverts commit d1c2e3ce3d
"spapr_drc.c: add hotunplug timeout for CPUs"

This reverts commit 51254ffb32
"spapr_drc.c: introduce unplug_timeout_timer"

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1911414
[2] https://lists.gnu.org/archive/html/qemu-devel/2021-03/msg04682.html

CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210401000437.131140-2-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-04-12 12:27:14 +10:00
Daniel Henrique Barboza
eb7f80fd26 spapr.c: send QAPI event when memory hotunplug fails
Recent changes allowed the pSeries machine to rollback the hotunplug
process for the DIMM when the guest kernel signals, via a
reconfiguration of the DR connector, that it's not going to release the
LMBs.

Let's also warn QAPI listerners about it. One place to do it would be
right after the unplug state is cleaned up,
spapr_clear_pending_dimm_unplug_state(). This would mean that the
function is now doing more than cleaning up the pending dimm state
though.

This patch does the following changes in spapr.c:

- send a QAPI event to inform that we experienced a failure in the
  hotunplug of the DIMM;

- rename spapr_clear_pending_dimm_unplug_state() to
  spapr_memory_unplug_rollback(). This is a better fit for what the
  function is now doing, and it makes callers care more about what the
  function goal is and less about spapr.c internals such as clearing
  the pending dimm unplug state.

Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210302141019.153729-3-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:09 +11:00
Daniel Henrique Barboza
4515a5f786 qemu_timer.c: add timer_deadline_ms() helper
The pSeries machine is using QEMUTimer internals to return the timeout
in seconds for a timer object, in hw/ppc/spapr.c, function
spapr_drc_unplug_timeout_remaining_sec().

Create a helper in qemu-timer.c to retrieve the deadline for a QEMUTimer
object, in ms, to avoid exposing timer internals to the PPC code.

CC: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210301124133.23800-2-danielhb413@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:09 +11:00
Daniel Henrique Barboza
fe1831eff8 spapr_drc.c: use DRC reconfiguration to cleanup DIMM unplug state
Handling errors in memory hotunplug in the pSeries machine is more
complex than any other device type, because there are all the
complications that other devices has, and more.

For instance, determining a timeout for a DIMM hotunplug must consider
if it's a Hash-MMU or a Radix-MMU guest, because Hash guests takes
longer to hotunplug DIMMs. The size of the DIMM is also a factor, given
that longer DIMMs naturally takes longer to be hotunplugged from the
kernel. And there's also the guest memory usage to be considered: if
there's a process that is consuming memory that would be lost by the
DIMM unplug, the kernel will postpone the unplug process until the
process finishes, and then initiate the regular hotunplug process. The
first two considerations are manageable, but the last one is a deal
breaker.

There is no sane way for the pSeries machine to determine the memory
load in the guest when attempting a DIMM hotunplug - and even if there
was a way, the guest can start using all the RAM in the middle of the
unplug process and invalidate our previous assumptions - and in result
we can't even begin to calculate a timeout for the operation. This means
that we can't implement a viable timeout mechanism for memory unplug in
pSeries.

Going back to why we would consider an unplug timeout, the reason is
that we can't know if the kernel is giving up the unplug. Turns out
that, sometimes, we can. Consider a failed memory hotunplug attempt
where the kernel will error out with the following message:

'pseries-hotplug-mem: Memory indexed-count-remove failed, adding any
removed LMBs'

This happens when there is a LMB that the kernel gave up in removing,
and the LMBs previously marked for removal are now being added back.
This happens in the pseries kernel in [1], dlpar_memory_remove_by_ic()
into dlpar_add_lmb(), and after that update_lmb_associativity_index().
In this function, the kernel is configuring the LMB DRC connector again.
Note that this is a valid usage in LOPAR, as stated in section
"ibm,configure-connector RTAS Call":

'A subsequent sequence of calls to ibm,configure-connector with the same
entry from the “ibm,drc-indexes” or “ibm,drc-info” property will restart
the configuration of devices which were not completely configured.'

We can use this kernel behavior in our favor. If a DRC connector
reconfiguration for a LMB that we marked as unplug pending happens, this
indicates that the kernel changed its mind about the unplug and is
reasserting that it will keep using all the LMBs of the DIMM. In this
case, it's safe to assume that the whole DIMM device unplug was
cancelled.

This patch hops into rtas_ibm_configure_connector() and, in the scenario
described above, clear the unplug state for the DIMM device. This will
not solve all the problems we still have with memory unplug, but it will
cover this case where the kernel reconfigures LMBs after a failed
unplug. We are a bit more resilient, without using an unreliable
timeout, and we didn't make the remaining error cases any worse.

[1] arch/powerpc/platforms/pseries/hotplug-memory.c

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210222194531.62717-6-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:09 +11:00
Daniel Henrique Barboza
d1c2e3ce3d spapr_drc.c: add hotunplug timeout for CPUs
There is a reliable way to make a CPU hotunplug fail in the pseries
machine. Hotplug a CPU A, then offline all other CPUs inside the guest
but A. When trying to hotunplug A the guest kernel will refuse to do it,
because A is now the last online CPU of the guest. PAPR has no 'error
callback' in this situation to report back to the platform, so the guest
kernel will deny the unplug in silent and QEMU will never know what
happened. The unplug pending state of A will remain until the guest is
shutdown or rebooted.

Previous attempts of fixing it (see [1] and [2]) were aimed at trying to
mitigate the effects of the problem. In [1] we were trying to guess
which guest CPUs were online to forbid hotunplug of the last online CPU
in the QEMU layer, avoiding the scenario described above because QEMU is
now failing in behalf of the guest. This is not robust because the last
online CPU of the guest can change while we're in the middle of the
unplug process, and our initial assumptions are now invalid. In [2] we
were accepting that our unplug process is uncertain and the user should
be allowed to spam the IRQ hotunplug queue of the guest in case the CPU
hotunplug fails.

This patch presents another alternative, using the timeout
infrastructure introduced in the previous patch. CPU hotunplugs in the
pSeries machine will now timeout after 15 seconds. This is a long time
for a single CPU unplug to occur, regardless of guest load - although
the user is *strongly* encouraged to *not* hotunplug devices from a
guest under high load - and we can be sure that something went wrong if
it takes longer than that for the guest to release the CPU (the same
can't be said about memory hotunplug - more on that in the next patch).

Timing out the unplug operation will reset the unplug state of the CPU
and allow the user to try it again, regardless of the error situation
that prevented the hotunplug to occur. Of all the not so pretty
fixes/mitigations for CPU hotunplug errors in pSeries, timing out the
operation is an admission that we have no control in the process, and
must assume the worst case if the operation doesn't succeed in a
sensible time frame.

[1] https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg03353.html
[2] https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg04400.html

Reported-by: Xujun Ma <xuma@redhat.com>
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1911414
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210222194531.62717-5-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:09 +11:00
Daniel Henrique Barboza
51254ffb32 spapr_drc.c: introduce unplug_timeout_timer
The LoPAR spec provides no way for the guest kernel to report failure of
hotplug/hotunplug events. This wouldn't be bad if those operations were
granted to always succeed, but that's far for the reality.

What ends up happening is that, in the case of a failed hotunplug,
regardless of whether it was a QEMU error or a guest misbehavior, the
pSeries machine is retaining the unplug state of the device in the
running guest.  This state is cleanup in machine reset, where it is
assumed that this state represents a device that is pending unplug, and
the device is hotunpluged from the board. Until the reset occurs, any
hotunplug operation of the same device is forbid because there is a
pending unplug state.

This behavior has at least one undesirable side effect. A long standing
pending unplug state is, more often than not, the result of a hotunplug
error. The user had to dealt with it, since retrying to unplug the
device is noy allowed, and then in the machine reset we're removing the
device from the guest. This means that we're failing the user twice -
failed to hotunplug when asked, then hotunplugged without notice.

Solutions to this problem range between trying to predict when the
hotunplug will fail and forbid the operation from the QEMU layer, from
opening up the IRQ queue to allow for multiple hotunplug attempts, from
telling the users to 'reboot the machine if something goes wrong'. The
first solution is flawed because we can't fully predict guest behavior
from QEMU, the second solution is a trial and error remediation that
counts on a hope that the unplug will eventually succeed, and the third
is ... well.

This patch introduces a crude, but effective solution to hotunplug
errors in the pSeries machine. For each unplug done, we'll timeout after
some time. If a certain amount of time passes, we'll cleanup the
hotunplug state from the machine.  During the timeout period, any unplug
operations in the same device will still be blocked. After that, we'll
assume that the guest failed the operation, and allow the user to try
again. If the timeout is too short we'll prevent legitimate hotunplug
situations to occur, so we'll need to overestimate the regular time an
unplug operation takes to succeed to account that.

The true solution for the hotunplug errors in the pSeries machines is a
PAPR change to allow for the guest to warn the platform about it. For
now, the work done in this timeout design can be used for the new PAPR
'abort hcall' in the future, given that for both cases we'll need code
to cleanup the existing unplug states of the DRCs.

At this moment we're adding the basic wiring of the timer into the DRC.
Next patch will use the timer to timeout failed CPU hotunplugs.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210222194531.62717-4-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:09 +11:00
Daniel Henrique Barboza
a03509cd2b spapr: rename spapr_drc_detach() to spapr_drc_unplug_request()
spapr_drc_detach() is not the best name for what the function does. The
function does not detach the DRC, it makes an uncommited attempt to do
it.  It'll mark the DRC as pending unplug, via the 'unplug_request'
flag, and only if the DRC state is drck->empty_state it will detach the
DRC, via spapr_drc_release().

This is a contrast with its pair spapr_drc_attach(), where the function
is indeed creating the DRC QOM object. If you know what
spapr_drc_attach() does, you can be misled into thinking that
spapr_drc_detach() is removing the DRC from QEMU internal state, which
isn't true.

The current role of this function is better described as a request for
detach, since there's no guarantee that we're going to detach the DRC in
the end.  Rename the function to spapr_drc_unplug_request to reflect
what is is doing.

The initial idea was to change the name to spapr_drc_detach_request(),
and later on change the unplug_request flag to detach_request. However,
unplug_request is a migratable boolean for a long time now and renaming
it is not worth the trouble. spapr_drc_unplug_request() setting
drc->unplug_request is more natural than spapr_drc_detach_request
setting drc->unplug_request.

Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210222194531.62717-3-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:08 +11:00
Daniel Henrique Barboza
66d10d32ac spapr_drc.c: use spapr_drc_release() in isolate_physical/set_unusable
When moving a physical DRC to "Available", drc_isolate_physical() will
move the DRC state to STATE_PHYSICAL_POWERON and, if the DRC is marked
for unplug, call spapr_drc_detach(). For physical DRCs,
drck->empty_state is STATE_PHYSICAL_POWERON, meaning that we're sure
that spapr_drc_detach() will end up calling spapr_drc_release() in the
end.

Likewise, for logical DRCs, drc_set_unusable will move the DRC to
"Unusable" state, setting drc->state to STATE_LOGICAL_UNUSABLE, which is
the drck->empty_state for logical DRCs. spapr_drc_detach() will call
spapr_drc_release() in this case as well.

In both scenarios, spapr_drc_detach() is being used as a
spapr_drc_release(), wrapper, where we also set unplug_requested (which
is already true, otherwise spapr_drc_detach() wouldn't be called in the
first place) and check if drc->state == drck->empty_state, which we also
know it's guaranteed to be true because we just set it.

Just use spapr_drc_release() in these functions to be clear of our
intentions in both these functions.

Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210222194531.62717-2-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:08 +11:00
Daniel Henrique Barboza
382907b100 spapr_drc.c: do not call spapr_drc_detach() in drc_isolate_logical()
drc_isolate_logical() is used to move the DRC from the "Configured" to
the "Available" state, erroring out if the DRC is in the unexpected
"Unisolate" state and doing nothing (with RTAS_OUT_SUCCESS) if the DRC
is already in "Available" or in "Unusable" state.

When moving from "Configured" to "Available", the DRC is moved to the
LOGICAL_AVAILABLE state, a drc->unplug_requested check is done and, if
true, spapr_drc_detach() is called.

What spapr_drc_detach() does then is:

- set drc->unplug_requested to true. In fact, this is the only place
where unplug_request is set to true;
- does nothing else if drc->state != drck->empty_state. If the DRC
state is equal to drck->empty_state, spapr_drc_release() is
called. For logical DRCs, drck->empty_state = LOGICAL_UNUSABLE.

In short, calling spapr_drc_detach() in drc_isolate_logical() does
nothing. It'll set unplug_request to true again ('again' since it was
already true - otherwise the function wouldn't be called), and will
return without calling spapr_drc_release() because the DRC is not in
LOGICAL_UNUSABLE, since drc_isolate_logical() just moved it to
LOGICAL_AVAILABLE. The only place where the logical DRC is released is
when called from drc_set_unusable(), when it is moved to the
"Unusable" state.  As it should, according to PAPR.

Even though calling spapr_drc_detach() in drc_isolate_logical() is
benign, removing it will avoid further thought about the matter. So
let's go ahead and do that.

As a note, this logic was introduced in commit bbf5c878ab. Since
then, the DRC handling code was refactored and enhanced, and PAPR
itself went through some changes in the DRC area as well. It is
expected that some assumptions we had back then are now deprecated.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210211225246.17315-2-danielhb413@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-03-10 09:07:08 +11:00
Greg Kurz
00f46c92a0 spapr: Add drc_ prefix to the DRC realize and unrealize functions
Use a less generic name for an easier experience with tools such as
cscope or grep.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20201218103400.689660-6-groug@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-01-06 11:09:59 +11:00
Greg Kurz
babb819f94 spapr: Introduce spapr_drc_reset_all()
No need to expose the way DRCs are traversed outside of spapr_drc.c.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20201218103400.689660-4-groug@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-01-06 11:09:59 +11:00
Greg Kurz
930ef3b5c2 spapr: Fix reset of transient DR connectors
Documentation of object_property_iter_init() clearly stipulates that
"it is forbidden to modify the property list while iterating". But this
is exactly what we do when resetting transient DR connectors during CAS.
The call to spapr_drc_reset() can finalize the hot-unplug sequence of a
PHB or a PCI bridge, both of which will then in turn destroy their PCI
DRCs. This could potentially invalidate the iterator. It is pure luck
that this haven't caused any issues so far.

Change spapr_drc_reset() to return true if it caused a device to be
removed. Restart from scratch in this case. This can potentially
increase the overall DRC reset time, especially with a high maxmem
which generates a lot of LMB DRCs. But this kind of setup is rare,
and so is the use case of rebooting a guest while doing hot-unplug.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20201218103400.689660-3-groug@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-01-06 11:09:59 +11:00
Greg Kurz
cd725bd748 spapr: Call spapr_drc_reset() for all DRCs at CAS
Non-transient DRCs are either in the empty or the ready state,
which means spapr_drc_reset() doesn't change their state. It
is thus not needed to do any checking. Call spapr_drc_reset()
unconditionally and squash spapr_drc_transient() into its
only user, spapr_drc_needed().

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20201218103400.689660-2-groug@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-01-06 11:09:59 +11:00
Greg Kurz
776e887f08 spapr: Fix DR properties of the root node
Section 13.5.2 of LoPAPR mandates various DR related indentifiers
for all hot-pluggable entities to be exposed in the "ibm,drc-indexes",
"ibm,drc-power-domains", "ibm,drc-names" and "ibm,drc-types" properties
of their parent node. These properties are created with spapr_dt_drc().

PHBs and LMBs are both children of the machine. Their DR identifiers
are thus supposed to be exposed in the afore mentioned properties of
the root node.

When PHB hot-plug support was added, an extra call to spapr_dt_drc()
was introduced: this overwrites the existing properties, previously
populated with the LMB identifiers, and they end up containing only
PHB identifiers. This went unseen so far because linux doesn't care,
but this is still not conformant with LoPAPR.

Fortunately spapr_dt_drc() is able to handle multiple DR entity types
at the same time. Use that to handle DR indentifiers for PHBs and LMBs
with a single call to spapr_dt_drc(). While here also account for PMEM
DR identifiers, which were forgotten when NVDIMM hot-plug support was
added. Also add an assert to prevent further misuse of spapr_dt_drc().

With -m 1G,maxmem=2G,slots=8 passed on the QEMU command line we get:

Without this patch:

/proc/device-tree/ibm,drc-indexes
		 0000001f 20000001 20000002 20000003
		 20000000 20000005 20000006 20000007
		 20000004 20000009 20000008 20000010
		 20000011 20000012 20000013 20000014
		 20000015 20000016 20000017 20000018
		 20000019 2000000a 2000000b 2000000c
		 2000000d 2000000e 2000000f 2000001a
		 2000001b 2000001c 2000001d 2000001e

These are the DRC indexes for the 31 possible PHBs.

With this patch:

/proc/device-tree/ibm,drc-indexes
		 0000002b 90000000 90000001 90000002
		 90000003 90000004 90000005 90000006
		 90000007 20000001 20000002 20000003
		 20000000 20000005 20000006 20000007
		 20000004 20000009 20000008 20000010
		 20000011 20000012 20000013 20000014
		 20000015 20000016 20000017 20000018
		 20000019 2000000a 2000000b 2000000c
		 2000000d 2000000e 2000000f 2000001a
		 2000001b 2000001c 2000001d 2000001e
		 80000004 80000005 80000006 80000007

And now we also have the 4 ((2G - 1G) / 256M) LMBs and the
8 (slots) PMEMs.

Fixes: 3998ccd092 ("spapr: populate PHB DRC entries for root DT node")
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <160794479566.35245.17809158217760761558.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2021-01-06 11:09:59 +11:00
Greg Kurz
bc370a659a spapr: spapr_drc_attach() cannot fail
All users are passing &error_abort already. Document the fact
that spapr_drc_attach() should only be passed a free DRC, which
is supposedly the case if appropriate checking is done earlier.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20201201113728.885700-5-groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-12-14 15:54:12 +11:00
Greg Kurz
eaf1ffbe15 spapr: Clarify why DR connectors aren't user creatable
DR connector is a device that emulates a firmware abstraction used by PAPR
compliant guests to manage hotplug/dynamic-reconfiguration of PHBs, PCI
devices, memory, and CPUs.

It is internally created by the spapr platform and requires to be owned by
either the machine (PHBs, CPUs, memory) or by a PHB (PCI devices).

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <160250199940.765467.6896806997161856576.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-10-28 01:08:53 +11:00
Greg Kurz
ebd226d221 spapr: Simplify error handling in prop_get_fdt()
Use the return value of visit_check_struct() and visit_check_list()
for error checking instead of local_err. This allows to get rid of
the error propagation overhead.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20200914123505.612812-10-groug@kaod.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-10-09 10:15:06 +11:00
Greg Kurz
17548fe64a spapr: Add a return value to spapr_drc_attach()
As recommended in "qapi/error.h", return true on success and false on
failure. This allows to reduce error propagation overhead in the callers.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20200914123505.612812-9-groug@kaod.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-10-09 10:15:06 +11:00
Markus Armbruster
7a309cc95b qom: Change object_get_canonical_path_component() not to malloc
object_get_canonical_path_component() returns a malloced copy of a
property name on success, null on failure.

19 of its 25 callers immediately free the returned copy.

Change object_get_canonical_path_component() to return the property
name directly.  Since modifying the name would be wrong, adjust the
return type to const char *.

Drop the free from the 19 callers become simpler, add the g_strdup()
to the other six.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200714160202.3121879-4-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
2020-07-21 16:23:43 +02:00
Markus Armbruster
668f62ec62 error: Eliminate error_propagate() with Coccinelle, part 1
When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.  Convert

    if (!foo(..., &err)) {
        ...
        error_propagate(errp, err);
        ...
        return ...
    }

to

    if (!foo(..., errp)) {
        ...
        ...
        return ...
    }

where nothing else needs @err.  Coccinelle script:

    @rule1 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
         if (
    (
    -        fun(args, &err, args2)
    +        fun(args, errp, args2)
    |
    -        !fun(args, &err, args2)
    +        !fun(args, errp, args2)
    |
    -        fun(args, &err, args2) op c1
    +        fun(args, errp, args2) op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    )
         }

    @rule2 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    expression var;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
    -    var = fun(args, &err, args2);
    +    var = fun(args, errp, args2);
         ... when != err
         if (
    (
             var
    |
             !var
    |
             var op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    |
             return var;
    )
         }

    @depends on rule1 || rule2@
    identifier err;
    @@
    -    Error *err = NULL;
         ... when != err

Not exactly elegant, I'm afraid.

The "when != lbl:" is necessary to avoid transforming

         if (fun(args, &err)) {
             goto out
         }
         ...
     out:
         error_propagate(errp, err);

even though other paths to label out still need the error_propagate().
For an actual example, see sclp_realize().

Without the "when strict", Coccinelle transforms vfio_msix_setup(),
incorrectly.  I don't know what exactly "when strict" does, only that
it helps here.

The match of return is narrower than what I want, but I can't figure
out how to express "return where the operand doesn't use @err".  For
an example where it's too narrow, see vfio_intx_enable().

Silently fails to convert hw/arm/armsse.c, because Coccinelle gets
confused by ARMSSE being used both as typedef and function-like macro
there.  Converted manually.

Line breaks tidied up manually.  One nested declaration of @local_err
deleted manually.  Preexisting unwanted blank line dropped in
hw/riscv/sifive_e.c.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-35-armbru@redhat.com>
2020-07-10 15:18:08 +02:00
Markus Armbruster
552d7f49ee qom: Crash more nicely on object_property_get_link() failure
Pass &error_abort instead of NULL where the returned value is
dereferenced or asserted to be non-null.  Drop a now redundant
assertion.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200707160613.848843-24-armbru@redhat.com>
2020-07-10 15:18:08 +02:00
Markus Armbruster
62a35aaa31 qapi: Use returned bool to check for failure, Coccinelle part
The previous commit enables conversion of

    visit_foo(..., &err);
    if (err) {
        ...
    }

to

    if (!visit_foo(..., errp)) {
        ...
    }

for visitor functions that now return true / false on success / error.
Coccinelle script:

    @@
    identifier fun =~ "check_list|input_type_enum|lv_start_struct|lv_type_bool|lv_type_int64|lv_type_str|lv_type_uint64|output_type_enum|parse_type_bool|parse_type_int64|parse_type_null|parse_type_number|parse_type_size|parse_type_str|parse_type_uint64|print_type_bool|print_type_int64|print_type_null|print_type_number|print_type_size|print_type_str|print_type_uint64|qapi_clone_start_alternate|qapi_clone_start_list|qapi_clone_start_struct|qapi_clone_type_bool|qapi_clone_type_int64|qapi_clone_type_null|qapi_clone_type_number|qapi_clone_type_str|qapi_clone_type_uint64|qapi_dealloc_start_list|qapi_dealloc_start_struct|qapi_dealloc_type_anything|qapi_dealloc_type_bool|qapi_dealloc_type_int64|qapi_dealloc_type_null|qapi_dealloc_type_number|qapi_dealloc_type_str|qapi_dealloc_type_uint64|qobject_input_check_list|qobject_input_check_struct|qobject_input_start_alternate|qobject_input_start_list|qobject_input_start_struct|qobject_input_type_any|qobject_input_type_bool|qobject_input_type_bool_keyval|qobject_input_type_int64|qobject_input_type_int64_keyval|qobject_input_type_null|qobject_input_type_number|qobject_input_type_number_keyval|qobject_input_type_size_keyval|qobject_input_type_str|qobject_input_type_str_keyval|qobject_input_type_uint64|qobject_input_type_uint64_keyval|qobject_output_start_list|qobject_output_start_struct|qobject_output_type_any|qobject_output_type_bool|qobject_output_type_int64|qobject_output_type_null|qobject_output_type_number|qobject_output_type_str|qobject_output_type_uint64|start_list|visit_check_list|visit_check_struct|visit_start_alternate|visit_start_list|visit_start_struct|visit_type_.*";
    expression list args;
    typedef Error;
    Error *err;
    @@
    -    fun(args, &err);
    -    if (err)
    +    if (!fun(args, &err))
         {
             ...
         }

A few line breaks tidied up manually.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200707160613.848843-19-armbru@redhat.com>
2020-07-10 15:18:08 +02:00
Markus Armbruster
9261ef5e32 Clean up some calls to ignore Error objects the right way
Receiving the error in a local variable only to free it is less clear
(and also less efficient) than passing NULL.  Clean up.

Cc: Daniel P. Berrange <berrange@redhat.com>
Cc: Jerome Forissier <jerome@forissier.org>
CC: Greg Kurz <groug@kaod.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20200630090351.1247703-4-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2020-07-02 06:25:28 +02:00
Markus Armbruster
ce189ab230 qdev: Convert bus-less devices to qdev_realize() with Coccinelle
All remaining conversions to qdev_realize() are for bus-less devices.
Coccinelle script:

    // only correct for bus-less @dev!

    @@
    expression errp;
    expression dev;
    @@
    -    qdev_init_nofail(dev);
    +    qdev_realize(dev, NULL, &error_fatal);

    @ depends on !(file in "hw/core/qdev.c") && !(file in "hw/core/bus.c")@
    expression errp;
    expression dev;
    symbol true;
    @@
    -    object_property_set_bool(OBJECT(dev), true, "realized", errp);
    +    qdev_realize(DEVICE(dev), NULL, errp);

    @ depends on !(file in "hw/core/qdev.c") && !(file in "hw/core/bus.c")@
    expression errp;
    expression dev;
    symbol true;
    @@
    -    object_property_set_bool(dev, true, "realized", errp);
    +    qdev_realize(DEVICE(dev), NULL, errp);

Note that Coccinelle chokes on ARMSSE typedef vs. macro in
hw/arm/armsse.c.  Worked around by temporarily renaming the macro for
the spatch run.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200610053247.1583243-57-armbru@redhat.com>
2020-06-15 22:06:04 +02:00
Markus Armbruster
df4fe0b291 qom: Drop @errp parameter of object_property_del()
Same story as for object_property_add(): the only way
object_property_del() can fail is when the property with this name
does not exist.  Since our property names are all hardcoded, failure
is a programming error, and the appropriate way to handle it is
passing &error_abort.  Most callers do that, the commit before
previous fixed one that didn't (and got the error handling wrong), and
the two remaining exceptions ignore errors.

Drop the @errp parameter.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-19-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2020-05-15 07:08:14 +02:00
Markus Armbruster
b69c3c21a5 qdev: Unrealize must not fail
Devices may have component devices and buses.

Device realization may fail.  Realization is recursive: a device's
realize() method realizes its components, and device_set_realized()
realizes its buses (which should in turn realize the devices on that
bus, except bus_set_realized() doesn't implement that, yet).

When realization of a component or bus fails, we need to roll back:
unrealize everything we realized so far.  If any of these unrealizes
failed, the device would be left in an inconsistent state.  Must not
happen.

device_set_realized() lets it happen: it ignores errors in the roll
back code starting at label child_realize_fail.

Since realization is recursive, unrealization must be recursive, too.
But how could a partly failed unrealize be rolled back?  We'd have to
re-realize, which can fail.  This design is fundamentally broken.

device_set_realized() does not roll back at all.  Instead, it keeps
unrealizing, ignoring further errors.

It can screw up even for a device with no buses: if the lone
dc->unrealize() fails, it still unregisters vmstate, and calls
listeners' unrealize() callback.

bus_set_realized() does not roll back either.  Instead, it stops
unrealizing.

Fortunately, no unrealize method can fail, as we'll see below.

To fix the design error, drop parameter @errp from all the unrealize
methods.

Any unrealize method that uses @errp now needs an update.  This leads
us to unrealize() methods that can fail.  Merely passing it to another
unrealize method cannot cause failure, though.  Here are the ones that
do other things with @errp:

* virtio_serial_device_unrealize()

  Fails when qbus_set_hotplug_handler() fails, but still does all the
  other work.  On failure, the device would stay realized with its
  resources completely gone.  Oops.  Can't happen, because
  qbus_set_hotplug_handler() can't actually fail here.  Pass
  &error_abort to qbus_set_hotplug_handler() instead.

* hw/ppc/spapr_drc.c's unrealize()

  Fails when object_property_del() fails, but all the other work is
  already done.  On failure, the device would stay realized with its
  vmstate registration gone.  Oops.  Can't happen, because
  object_property_del() can't actually fail here.  Pass &error_abort
  to object_property_del() instead.

* spapr_phb_unrealize()

  Fails and bails out when remove_drcs() fails, but other work is
  already done.  On failure, the device would stay realized with some
  of its resources gone.  Oops.  remove_drcs() fails only when
  chassis_from_bus()'s object_property_get_uint() fails, and it can't
  here.  Pass &error_abort to remove_drcs() instead.

Therefore, no unrealize method can fail before this patch.

device_set_realized()'s recursive unrealization via bus uses
object_property_set_bool().  Can't drop @errp there, so pass
&error_abort.

We similarly unrealize with object_property_set_bool() elsewhere,
always ignoring errors.  Pass &error_abort instead.

Several unrealize methods no longer handle errors from other unrealize
methods: virtio_9p_device_unrealize(),
virtio_input_device_unrealize(), scsi_qdev_unrealize(), ...
Much of the deleted error handling looks wrong anyway.

One unrealize methods no longer ignore such errors:
usb_ehci_pci_exit().

Several realize methods no longer ignore errors when rolling back:
v9fs_device_realize_common(), pci_qdev_unrealize(),
spapr_phb_realize(), usb_qdev_realize(), vfio_ccw_realize(),
virtio_device_realize().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-17-armbru@redhat.com>
2020-05-15 07:08:14 +02:00
Markus Armbruster
d2623129a7 qom: Drop parameter @errp of object_property_add() & friends
The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]
2020-05-15 07:07:58 +02:00
Markus Armbruster
ddfb0baaf2 qom: Clean up inconsistent use of gchar * vs. char *
Uses of gchar * in qom/object.h:

* ObjectProperty member @name

  Functions that take a property name argument all use char *.  Change
  the member to match.

* ObjectProperty member @type

  Functions that take a property type argument or return it all use
  char *.  Change the member to match.

* ObjectProperty member @description

  Functions that take a property description argument all use char *.
  Change the member to match.

* object_resolve_path_component() parameter @part

  Path components are property names.  Most callers pass char *
  arguments.  Change the parameter to match.  Adjust the few callers
  that pass gchar * to pass char *.

* Return value of object_get_canonical_path_component(),
  object_get_canonical_path()

  Most callers convert their return values right back to char *.
  Change the return value to match.  Adjust the few callers where that
  would add a conversion to gchar * to use char * instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-3-armbru@redhat.com>
2020-05-15 06:26:02 +02:00
Felipe Franciosi
836e1b3813 qom/object: enable setter for uint types
Traditionally, the uint-specific property helpers only offer getters.
When adding object (or class) uint types, one must therefore use the
generic property helper if a setter is needed (and probably duplicate
some code writing their own getters/setters).

This enhances the uint-specific property helper APIs by adding a
bitwise-or'd 'flags' field and modifying all clients of that API to set
this paramater to OBJ_PROP_FLAG_READ. This maintains the current
behaviour whilst allowing others to also set OBJ_PROP_FLAG_WRITE (or use
the more convenient OBJ_PROP_FLAG_READWRITE) in the future (which will
automatically install a setter). Other flags may be added later.

Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 23:02:23 +01:00
Greg Kurz
ab8584349c spapr: Fix handling of unplugged devices during CAS and migration
We already detect if a device is being hot plugged before CAS to trigger
a CAS reboot and during migration to migrate the state of the associated
DRC. But hot unplugging a device is also an asynchronous operation that
requires the guest to take action. This means that if the guest is migrated
after the hot unplug event was sent but before it could release the device
with RTAS, the destination QEMU doesn't know about the pending unplug
operation and doesn't actually remove the device when the guest finally
releases it.

Similarly, if the unplug request is fired before CAS, the guest isn't
notified of the change, just like with hotplug. It ends up booting with
the device still present in the DT and configures it, just like it was
never removed. Even weirder, since the event is still queued, it will
be eventually processed when some other unrelated event is posted to
the guest.

Enhance spapr_drc_transient() to also return true if an unplug request is
pending. This fixes the issue at CAS with a CAS reboot request and
causes the DRC state to be migrated. Some extra care is still needed to
inform the destination that an unplug request is pending : migrate the
unplug_requested field of the DRC in an optional subsection. This might
break backwards migration, but this is still better than ending with
an inconsistent guest.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <158169248798.3465937.1108351365840514270.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-02-21 09:15:04 +11:00
Greg Kurz
4b63db1289 spapr: Don't use spapr_drc_needed() in CAS code
We currently don't support hotplug of devices between boot and CAS. If
this happens a CAS reboot is triggered. We detect this during CAS using
the spapr_drc_needed() function which is essentially a VMStateDescription
.needed callback. Even if the condition for CAS reboot happens to be the
same as for DRC migration, it looks wrong to piggyback a migration helper
for this.

Introduce a helper with slightly more explicit name and use it in both CAS
and DRC migration code. Since a subsequent patch will enhance this helper
to cover the case of hot unplug, let's go for spapr_drc_transient(). While
here convert spapr_hotplugged_dev_before_cas() to the "transient" wording as
well.

This doesn't change any behaviour.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <158169248180.3465937.9531405453362718771.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-02-21 09:15:04 +11:00
Shivaprasad G Bhat
ee3a71e366 spapr: Add NVDIMM device support
Add support for NVDIMM devices for sPAPR. Piggyback on existing nvdimm
device interface in QEMU to support virtual NVDIMM devices for Power.
Create the required DT entries for the device (some entries have
dummy values right now).

The patch creates the required DT node and sends a hotplug
interrupt to the guest. Guest is expected to undertake the normal
DR resource add path in response and start issuing PAPR SCM hcalls.

The device support is verified based on the machine version unlike x86.

This is how it can be used ..
Ex :
For coldplug, the device to be added in qemu command line as shown below
-object memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/tmp/nvdimm0,share=yes,size=1073872896
-device nvdimm,label-size=128k,uuid=75a3cdd7-6a2f-4791-8d15-fe0a920e8e9e,memdev=memnvdimm0,id=nvdimm0,slot=0

For hotplug, the device to be added from monitor as below
object_add memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/tmp/nvdimm0,share=yes,size=1073872896
device_add nvdimm,label-size=128k,uuid=75a3cdd7-6a2f-4791-8d15-fe0a920e8e9e,memdev=memnvdimm0,id=nvdimm0,slot=0

Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
               [Early implementation]
Message-Id: <158131058078.2897.12767731856697459923.stgit@lep8c.aus.stglabs.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-02-21 09:15:04 +11:00
Marc-André Lureau
3cad405bab vmstate: replace DeviceState with VMStateIf
Replace DeviceState dependency with VMStateIf on vmstate API.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
2020-01-06 18:41:32 +04:00
Shivaprasad G Bhat
dbd26f2f7f ppc: fix memory leak in spapr_dt_drc()
Leaking the drc_name while preparing the DT properties.
Fixing that.

Also, remove the const qualifier from spapr_drc_name().

Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Message-Id: <156335159028.82682.5404622104535818162.stgit@lep8c.aus.stglabs.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2019-08-21 17:17:11 +10:00
Markus Armbruster
a27bd6c779 Include hw/qdev-properties.h less
In my "build everything" tree, changing hw/qdev-properties.h triggers
a recompile of some 2700 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h).

Many places including hw/qdev-properties.h (directly or via hw/qdev.h)
actually need only hw/qdev-core.h.  Include hw/qdev-core.h there
instead.

hw/qdev.h is actually pointless: all it does is include hw/qdev-core.h
and hw/qdev-properties.h, which in turn includes hw/qdev-core.h.
Replace the remaining uses of hw/qdev.h by hw/qdev-properties.h.

While there, delete a few superfluous inclusions of hw/qdev-core.h.

Touching hw/qdev-properties.h now recompiles some 1200 objects.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190812052359.30071-22-armbru@redhat.com>
2019-08-16 13:31:53 +02:00
Markus Armbruster
d645427057 Include migration/vmstate.h less
In my "build everything" tree, changing migration/vmstate.h triggers a
recompile of some 2700 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h).

hw/hw.h supposedly includes it for convenience.  Several other headers
include it just to get VMStateDescription.  The previous commit made
that unnecessary.

Include migration/vmstate.h only where it's still needed.  Touching it
now recompiles only some 1600 objects.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20190812052359.30071-16-armbru@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2019-08-16 13:31:52 +02:00
Markus Armbruster
71e8a91585 Include sysemu/reset.h a lot less
In my "build everything" tree, changing sysemu/reset.h triggers a
recompile of some 2600 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h).

The main culprit is hw/hw.h, which supposedly includes it for
convenience.

Include sysemu/reset.h only where it's needed.  Touching it now
recompiles less than 200 objects.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190812052359.30071-9-armbru@redhat.com>
2019-08-16 13:31:52 +02:00