The number of queues supported by the slave is queried with
message VHOST_USER_GET_QUEUE_NUM, not with message
VHOST_USER_GET_PROTOCOL_FEATURES.
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This function should be declared in generic header file so we can
utilize it.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The loading time of a VM is quite significant when its virtio
devices use a large amount of virt-queues (e.g. a virtio-serial
device with max_ports=511). Most of the time is spend in the
creation of all the required event notifiers (ioeventfd and memory
regions).
This patch pack all the changes to the memory regions in a
single memory transaction.
Reported-by: Sitong Liu <siliu@redhat.com>
Reported-by: Xiaoling Gao <xiagao@redhat.com>
Signed-off-by: Gal Hammer <ghammer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Use the EventNotifier's cleanup callback function to execute the
event_notifier_cleanup function after kvm unregistered the eventfd.
This change supports running the virtio_bus_set_host_notifier
function inside a memory region transaction. Otherwise, a closed
fd is sent to kvm, which results in a failure.
Signed-off-by: Gal Hammer <ghammer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Adding a cleanup callback function to the EventNotifier struct
which allows users to execute event_notifier_cleanup in a
different context.
Signed-off-by: Gal Hammer <ghammer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit introduces a vhost-user-blk backend device, it uses UNIX
domain socket to communicate with QEMU. The vhost-user-blk sample
application should be used with QEMU vhost-user-blk-pci device.
To use it, complie with:
make vhost-user-blk
and start like this:
vhost-user-blk -b /dev/sdb -s /path/vhost.socket
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Enable VHOST_USER_GET_CONFIG/VHOST_USER_SET_CONFIG messages in
libvhost-user library, users can implement their own I/O target
based on the library. This enable the virtio config space delivered
between QEMU host device and the I/O target.
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit introduces a new vhost-user device for block, it uses a
chardev to connect with the backend, same with Qemu virito-blk device,
Guest OS still uses the virtio-blk frontend driver.
To use it, start QEMU with command line like this:
qemu-system-x86_64 \
-chardev socket,id=char0,path=/path/vhost.socket \
-device vhost-user-blk-pci,chardev=char0,num-queues=2, \
bootindex=2... \
Users can use different parameters for `num-queues` and `bootindex`.
Different with exist Qemu virtio-blk host device, it makes more easy
for users to implement their own I/O processing logic, such as all
user space I/O stack against hardware block device. It uses the new
vhost messages(VHOST_USER_GET_CONFIG) to get block virtio config
information from backend process.
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add VHOST_USER_GET_CONFIG/VHOST_USER_SET_CONFIG messages which can be
used for live migration of vhost user devices, also vhost user devices
can benefit from the messages to get/set virtio config space from/to the
I/O target. For the purpose to support virtio config space change,
VHOST_USER_SLAVE_CONFIG_CHANGE_MSG message is added as the event notifier
in case virtio config space change in the slave I/O target.
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Highlight: new CPU models that expose CPU features that guests
can use to mitigate CVE-2017-5715 (Spectre variant #2).
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Merge remote-tracking branch 'remotes/ehabkost/tags/x86-pull-request' into staging
x86 queue, 2018-01-17
Highlight: new CPU models that expose CPU features that guests
can use to mitigate CVE-2017-5715 (Spectre variant #2).
# gpg: Signature made Thu 18 Jan 2018 02:00:03 GMT
# gpg: using RSA key 0x2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF D1AA 2807 936F 984D C5A6
* remotes/ehabkost/tags/x86-pull-request:
i386: Add EPYC-IBPB CPU model
i386: Add new -IBRS versions of Intel CPU models
i386: Add FEAT_8000_0008_EBX CPUID feature word
i386: Add spec-ctrl CPUID bit
i386: Add support for SPEC_CTRL MSR
i386: Change X86CPUDefinition::model_id to const char*
target/i386: add clflushopt to "Skylake-Server" cpu model
pc: add 2.12 machine types
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Another pull request for ppc related patches. The most interesting
thing here is the new capabilities framework for the pseries machine
type. This gives us better handling of several existing
incompatibilities between TCG, PR and HV KVM, as well as new ones that
arise with POWER9. Further, it will allow reasonable handling of the
advertisement of features necessary to mitigate the recent CVEs
(Spectre and Meltdown).
In addition there's:
* Improvide handling of different "vsmt" modes
* Significant enhancements to the "pnv" machine type
* Assorted other bugfixes
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Merge remote-tracking branch 'remotes/dgibson/tags/ppc-for-2.12-20180117' into staging
ppc patch queue 2017-01-17
Another pull request for ppc related patches. The most interesting
thing here is the new capabilities framework for the pseries machine
type. This gives us better handling of several existing
incompatibilities between TCG, PR and HV KVM, as well as new ones that
arise with POWER9. Further, it will allow reasonable handling of the
advertisement of features necessary to mitigate the recent CVEs
(Spectre and Meltdown).
In addition there's:
* Improvide handling of different "vsmt" modes
* Significant enhancements to the "pnv" machine type
* Assorted other bugfixes
# gpg: Signature made Wed 17 Jan 2018 02:21:50 GMT
# gpg: using RSA key 0x6C38CACA20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>"
# gpg: aka "David Gibson (Red Hat) <dgibson@redhat.com>"
# gpg: aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>"
# gpg: aka "David Gibson (kernel.org) <dwg@kernel.org>"
# Primary key fingerprint: 75F4 6586 AE61 A66C C44E 87DC 6C38 CACA 20D9 B392
* remotes/dgibson/tags/ppc-for-2.12-20180117: (22 commits)
target-ppc: Fix booke206 tlbwe TLB instruction
target/ppc: add support for POWER9 HILE
ppc/pnv: change initrd address
ppc/pnv: fix XSCOM core addressing on POWER9
ppc/pnv: introduce pnv*_is_power9() helpers
ppc/pnv: change core mask for POWER9
ppc/pnv: use POWER9 DD2 processor
tests/boot-serial-test: fix powernv support
ppc/pnv: Update skiboot firmware image
spapr: Adjust default VSMT value for better migration compatibility
spapr: Allow some cases where we can't set VSMT mode in the kernel
target/ppc: Clarify compat mode max_threads value
ppc: Change Power9 compat table to support at most 8 threads/core
spapr: Remove unnecessary 'options' field from sPAPRCapabilityInfo
hw/ppc/spapr_caps: Rework spapr_caps to use uint8 internal representation
spapr: Handle Decimal Floating Point (DFP) as an optional capability
spapr: Handle VMX/VSX presence as an spapr capability flag
target/ppc: Clean up probing of VMX, VSX and DFP availability on KVM
spapr: Validate capabilities on migration
spapr: Treat Hardware Transactional Memory (HTM) as an optional capability
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
When using a mouse's scroll wheel in a guest with
the cocoa front-end, the mouse pointer moves up
and down instead of scrolling the window. This
patch fixes this problem.
Signed-off-by: John Arbuckle <programmingkidx@gmail.com>
Message-id: 20180108180707.7976-1-programmingkidx@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20171122101958.17065-6-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Rather than making every callsite perform length sanity checks
and error reporting, add the helper functions nbd_opt_read()
and nbd_opt_drop() that use the length stored in the client
struct; also add an assertion that optlen is 0 before any
option (ie. any previous option was fully handled), complementing
the assertion added in an earlier patch that optlen is 0 after
all negotiation completes.
Note that the call in nbd_negotiate_handle_export_name() does
not use the new helper (in part because the server cannot
reply to NBD_OPT_EXPORT_NAME - it either succeeds or the
connection drops).
Based on patches by Vladimir Sementsov-Ogievskiy.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180110230825.18321-6-eblake@redhat.com>
This will be useful for the next patch.
Based on a patch by Vladimir Sementsov-Ogievskiy
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180110230825.18321-5-eblake@redhat.com>
When a client abruptly disconnects before we've finished reading
the name sent with NBD_OPT_EXPORT_NAME, we are better off logging
the failure as EIO (we can't communicate with the client), rather
than EINVAL (the client sent bogus data).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180110230825.18321-4-eblake@redhat.com>
Instead of passing currently negotiating option and its length to
many of negotiation functions let's just store them on NBDClient
struct to be state-variables of negotiation phase.
This unifies semantics of negotiation functions and allows
tracking changes of remaining option length in future patches.
Asssert that optlen is back to 0 after negotiation (including
old-style connections which don't negotiate), although we need
more patches before we can assert optlen is 0 between options
during negotiation.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20171122101958.17065-2-vsementsov@virtuozzo.com>
[eblake: rebase, commit message tweak, assert !optlen after
negotiation completes]
Signed-off-by: Eric Blake <eblake@redhat.com>
No semantic change, but will make it easier for an upcoming patch
to refactor code without having to add forward declarations. Fix
a poor comment while at it.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180110230825.18321-2-eblake@redhat.com>
EPYC-IBPB is a copy of the EPYC CPU model with
just CPUID_8000_0008_EBX_IBPB added.
Cc: Jiri Denemark <jdenemar@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180109154519.25634-7-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
The new MSR IA32_SPEC_CTRL MSR was introduced by a recent Intel
microcode updated and can be used by OSes to mitigate
CVE-2017-5715. Unfortunately we can't change the existing CPU
models without breaking existing setups, so users need to
explicitly update their VM configuration to use the new *-IBRS
CPU model if they want to expose IBRS to guests.
The new CPU models are simple copies of the existing CPU models,
with just CPUID_7_0_EDX_SPEC_CTRL added and model_id updated.
Cc: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180109154519.25634-6-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Add the new feature word and the "ibpb" feature flag.
Based on a patch by Paolo Bonzini.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180109154519.25634-5-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Add the feature name and a CPUID_7_0_EDX_SPEC_CTRL macro.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180109154519.25634-4-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
It is valid to have a 48-character model ID on CPUID, however the
definition of X86CPUDefinition::model_id is char[48], which can
make the compiler drop the null terminator from the string.
If a CPU model happens to have 48 bytes on model_id, "-cpu help"
will print garbage and the object_property_set_str() call at
x86_cpu_load_def() will read data outside the model_id array.
We could increase the array size to 49, but this would mean the
compiler would not issue a warning if a 49-char string is used by
mistake for model_id.
To make things simpler, simply change model_id to be const char*,
and validate the string length using an assert() on
x86_register_cpudef_type().
Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180109154519.25634-2-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
CPUID_7_0_EBX_CLFLUSHOPT is missed in current "Skylake-Server" cpu
model. Add it to "Skylake-Server" cpu model on pc-i440fx-2.12 and
pc-q35-2.12. Keep it disabled in "Skylake-Server" cpu model on older
machine types.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Message-Id: <20171219033730.12748-3-haozhong.zhang@intel.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
When overwritting a valid TLB entry with a new one, the previous page
were not flushed in QEMU TLB, leading to incoherent mapping. This commit
fixes this.
Signed-off-by: Luc MICHEL <luc.michel@git.antfield.fr>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
When skiboot starts, it first clears the CPU structs for all possible
CPUs on a system :
for (i = 0; i <= cpu_max_pir; i++)
memset(&cpu_stacks[i].cpu, 0, sizeof(struct cpu_thread));
On POWER9, cpu_max_pir is quite big, 0x7fff, and the skiboot cpu_stacks
array overlaps with the memory region in which QEMU maps the initramfs
file. Move it upwards in memory to keep it safe.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The XSCOM base address of the core chiplet was wrongly calculated. Use
the OPAL macros to fix that and do a couple of renames.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
These are useful when instantiating device models which are shared
between the POWER8 and the POWER9 processor families.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
When addressed by XSCOM, the first core has the 0x20 chiplet ID but
the CPU PIR can start at 0x0.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
commit 1ed9c8af50 ("target/ppc: Add POWER9 DD2.0 model information")
deprecated the POWER9 model v1.0.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Recent commit introduced the firmware image skiboot 5.9 which
has a different first line ouput.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This is skiboot 5.9 (commit e0ee24c2). It brings improved POWER9
support among many other things. Built from submodule.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
fa98fbfc "PC: KVM: Support machine option to set VSMT mode" introduced the
"vsmt" parameter for the pseries machine type, which controls the spacing
of the vcpu ids of thread 0 for each virtual core. This was done to bring
some consistency and stability to how that was done, while still allowing
backwards compatibility for migration and otherwise.
The default value we used for vsmt was set to the max of the host's
advertised default number of threads and the number of vthreads per vcore
in the guest. This was done to continue running without extra parameters
on older KVM versions which don't allow the VSMT value to be changed.
Unfortunately, even that smaller than before leakage of host configuration
into guest visible configuration still breaks things. Specifically a guest
with 4 (or less) vthread/vcore will get a different vsmt value when
running on a POWER8 (vsmt==8) and POWER9 (vsmt==4) host. That means the
vcpu ids don't line up so you can't migrate between them, though you should
be able to.
Long term we really want to make vsmt == smp_threads for sufficiently
new machine types. However, that means that qemu will then require a
sufficiently recent KVM (one which supports changing VSMT) - that's still
not widely enough deployed to be really comfortable to do.
In the meantime we need some default that will work as often as
possible. This patch changes that default to 8 in all circumstances.
This does change guest visible behaviour (including for existing
machine versions) for many cases - just not the most common/important
case.
Following is case by case justification for why this is still the least
worst option. Note that any of the old behaviours can still be duplicated
after this patch, it's just that it requires manual intervention by
setting the vsmt property on the command line.
KVM HV on POWER8 host:
This is the overwhelmingly common case in production setups, and is
unchanged by design. POWER8 hosts will advertise a default VSMT mode
of 8, and > 8 vthreads/vcore isn't permitted
KVM HV on POWER7 host:
Will break, but POWER7s allowing KVM were never released to the public.
KVM HV on POWER9 host:
Not yet released to the public, breaking this now will reduce other
breakage later.
KVM HV on PowerPC 970:
Will theoretically break it, but it was barely supported to begin with
and already required various user visible hacks to work. Also so old
that I just don't care.
TCG:
This is the nastiest one; it means migration of TCG guests (without
manual vsmt setting) will break. Since TCG is rarely used in production
I think this is worth it for the other benefits. It does also remove
one more barrier to TCG<->KVM migration which could be interesting for
debugging applications.
KVM PR:
As with TCG, this will break migration of existing configurations,
without adding extra manual vsmt options. As with TCG, it is rare in
production so I think the benefits outweigh breakages.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
At present if we require a vsmt mode that's not equal to the kernel's
default, and the kernel doesn't let us change it (e.g. because it's an old
kernel without support) then we always fail.
But in fact we can cope with the kernel having a different vsmt as long as
a) it's >= the actual number of vthreads/vcore (so that guest threads
that are supposed to be on the same core act like it)
b) it's a submultiple of the requested vsmt mode (so that guest threads
spaced by the vsmt value will act like they're on different cores)
Allowing this case gives us a bit more freedom to adjust the vsmt behaviour
without breaking existing cases.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Tested-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
We recently had some discussions that were sidetracked for a while, because
nearly everyone misapprehended the purpose of the 'max_threads' field in
the compatiblity modes table. It's all about guest expectations, not host
expectations or support (that's handled elsewhere).
In an attempt to avoid a repeat of that confusion, rename the field to
'max_vthreads' and add an explanatory comment.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Increases the max smt mode to 8 for Power9. That's because KVM supports
smt emulation in this platform so QEMU should allow users to use it as
well.
Today if we try to pass -smp ...,threads=8, QEMU will silently truncate
it to smt4 mode and may cause a crash if we try to perform a cpu
hotplug.
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
[dwg: Added an explanatory comment]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The options field here is intended to list the available values for the
capability. It's not used yet, because the existing capabilities are
boolean.
We're going to add capabilities that aren't, but in that case the info on
the possible values can be folded into the .description field.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently spapr_caps are tied to boolean values (on or off). This patch
reworks the caps so that they can have any uint8 value. This allows more
capabilities with various values to be represented in the same way
internally. Capabilities are numbered in ascending order. The internal
representation of capability values is an array of uint8s in the
sPAPRMachineState, indexed by capability number.
Capabilities can have their own name, description, options, getter and
setter functions, type and allow functions. They also each have their own
section in the migration stream. Capabilities are only migrated if they
were explictly set on the command line, with the assumption that
otherwise the default will match.
On migration we ensure that the capability value on the destination
is greater than or equal to the capability value from the source. So
long at this remains the case then the migration is considered
compatible and allowed to continue.
This patch implements generic getter and setter functions for boolean
capabilities. It also converts the existings cap-htm, cap-vsx and
cap-dfp capabilities to this new format.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Decimal Floating Point has been available on POWER7 and later (server)
cpus. However, it can be disabled on the hypervisor, meaning that it's
not available to guests.
We currently handle this by conditionally advertising DFP support in the
device tree depending on whether the guest CPU model supports it - which
can also depend on what's allowed in the host for -cpu host. That can lead
to confusion on migration, since host properties are silently affecting
guest visible properties.
This patch handles it by treating it as an optional capability for the
pseries machine type.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
We currently have some conditionals in the spapr device tree code to decide
whether or not to advertise the availability of the VMX (aka Altivec) and
VSX vector extensions to the guest, based on whether the guest cpu has
those features.
This can lead to confusion and subtle failures on migration, since it makes
a guest visible change based only on host capabilities. We now have a
better mechanism for this, in spapr capabilities flags, which explicitly
depend on user options rather than host capabilities.
Rework the advertisement of VSX and VMX based on a new VSX capability. We
no longer bother with a conditional for VMX support, because every CPU
that's ever been supported by the pseries machine type supports VMX.
NOTE: Some userspace distributions (e.g. RHEL7.4) already rely on
availability of VSX in libc, so using cap-vsx=off may lead to a fatal
SIGILL in init.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
When constructing the "host" cpu class we modify whether the VMX and VSX
vector extensions and DFP (Decimal Floating Point) are available
based on whether KVM can support those instructions. This can depend on
policy in the host kernel as well as on the actual host cpu capabilities.
However, the way we probe for this is not very nice: we explicitly check
the host's device tree. That works in practice, but it's not really
correct, since the device tree is a property of the host kernel's platform
which we don't really know about. We get away with it because the only
modern POWER platforms happen to encode VMX, VSX and DFP availability in
the device tree in the same way.
Arguably we should have an explicit KVM capability for this, but we haven't
needed one so far. Barring specific KVM policies which don't yet exist,
each of these instruction classes will be available in the guest if and
only if they're available in the qemu userspace process. We can determine
that from the ELF AUX vector we're supplied with.
Once reworked like this, there are no more callers for kvmppc_get_vmx() and
kvmppc_get_dfp() so remove them.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Now that the "pseries" machine type implements optional capabilities (well,
one so far) there's the possibility of having different capabilities
available at either end of a migration. Although arguably a user error,
it would be nice to catch this situation and fail as gracefully as we can.
This adds code to migrate the capabilities flags. These aren't pulled
directly into the destination's configuration since what the user has
specified on the destination command line should take precedence. However,
they are checked against the destination capabilities.
If the source was using a capability which is absent on the destination,
we fail the migration, since that could easily cause a guest crash or other
bad behaviour. If the source lacked a capability which is present on the
destination we warn, but allow the migration to proceed.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
This adds an spapr capability bit for Hardware Transactional Memory. It is
enabled by default for pseries-2.11 and earlier machine types. with POWER8
or later CPUs (as it must be, since earlier qemu versions would implicitly
allow it). However it is disabled by default for the latest pseries-2.12
machine type.
This means that with the latest machine type, HTM will not be available,
regardless of CPU, unless it is explicitly enabled on the command line.
That change is made on the basis that:
* This way running with -M pseries,accel=tcg will start with whatever cpu
and will provide the same guest visible model as with accel=kvm.
- More specifically, this means existing make check tests don't have
to be modified to use cap-htm=off in order to run with TCG
* We hope to add a new "HTM without suspend" feature in the not too
distant future which could work on both POWER8 and POWER9 cpus, and
could be enabled by default.
* Best guesses suggest that future POWER cpus may well only support the
HTM-without-suspend model, not the (frankly, horribly overcomplicated)
POWER8 style HTM with suspend.
* Anecdotal evidence suggests problems with HTM being enabled when it
wasn't wanted are more common than being missing when it was.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Because PAPR is a paravirtual environment access to certain CPU (or other)
facilities can be blocked by the hypervisor. PAPR provides ways to
advertise in the device tree whether or not those features are available to
the guest.
In some places we automatically determine whether to make a feature
available based on whether our host can support it, in most cases this is
based on limitations in the available KVM implementation.
Although we correctly advertise this to the guest, it means that host
factors might make changes to the guest visible environment which is bad:
as well as generaly reducing reproducibility, it means that a migration
between different host environments can easily go bad.
We've mostly gotten away with it because the environments considered mature
enough to be well supported (basically, KVM on POWER8) have had consistent
feature availability. But, it's still not right and some limitations on
POWER9 is going to make it more of an issue in future.
This introduces an infrastructure for defining "sPAPR capabilities". These
are set by default based on the machine version, masked by the capabilities
of the chosen cpu, but can be overriden with machine properties.
The intention is at reset time we verify that the requested capabilities
can be supported on the host (considering TCG, KVM and/or host cpu
limitations). If not we simply fail, rather than silently modifying the
advertised featureset to the guest.
This does mean that certain configurations that "worked" may now fail, but
such configurations were already more subtly broken.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
As stated in the 1ad9f0a464 commit log, the returned entries are not
a whole PTEG. It was not a problem before 1ad9f0a464 as it would read
a single record assuming it contains a whole PTEG but now the code tries
reading the entire PTEG and "if ((n - i) < invalid)" produces negative
values which then are converted to size_t for memset() and that throws
seg fault.
This fixes the math.
While here, fix the last @i increment as well.
Fixes: 1ad9f0a464 "target/ppc: Fix KVM-HV HPTE accessors"
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
