The dynamic reconfiguration (hotplug) code for the pseries machine type
uses a "DR connector" QOM object for each resource it will be possible
to hotplug. Each of these is added to its owner using
object_property_add_child(owner, "dr-connector[*], ...);
That works ok, mostly, but it means that the property indices are
arbitrary, depending on the order in which the connectors are constructed.
That might line up to something useful, but it doesn't have to.
It will get worse once we add hotplug RAM support. That will add a DR
connector object for every 256MB of potential memory. So if maxmem=2T,
for example, there are 8192 objects under the same parent.
The QOM interfaces aren't really designed for this. In particular
object_property_add() with [*] has O(n^2) time complexity (in the number of
existing children): first it has a linear search through array indices to
find a free slot, each of which is attempted to a recursive call to
object_property_add() with a specific [N]. Those calls are O(n) because
there's a linear search through all properties to check for duplicates.
By using a meaningful index value, which we already know is unique we can
avoid the [*] special behaviour. That lets us reduce the total time for
creating the DR objects from O(n^3) to O(n^2).
O(n^2) is still kind of crappy, but it's enough to reduce the startup time
of qemu (with in-progress memory hotplug support) with maxmem=2T from ~20
minutes to ~4 seconds.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Certain methods in sPAPRDRConnector objects are only ever called by
RTAS and in many cases are responsible for the logic that determines
the RTAS return codes.
Rather than having a level of indirection requiring RTAS code to
re-interpret return values from such methods to determine the
appropriate return code, just pass them through directly.
This requires changing method return types to uint32_t to match the
type of values currently passed to RTAS helpers.
In the case of read accesses like drc->entity_sense() where we weren't
previously reporting any errors, just the read value, we modify the
function to return RTAS return code, and pass the read value back via
reference.
Suggested-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Logical resources start with allocation-state:UNUSABLE /
isolation-state:ISOLATED. During hotplug, guests will transition
them to allocation-state:USABLE, and then to
isolation-state:UNISOLATED.
For cases where we cannot transition to allocation-state:USABLE,
in this case due to no device/resource being association with
the logical DRC, we should return an error -3.
For physical DRCs, we default to allocation-state:USABLE and stay
there, so in this case we should report an error -3 when the guest
attempts to make the isolation-state:ISOLATED transition for a DRC
with no device associated.
These are as documented in PAPR 2.7, 13.5.3.4.
We also ensure allocation-state:USABLE when the guest attempts
transition to isolation-state:UNISOLATED to deal with misbehaving
guests attempting to bring online an unallocated logical resource.
This is as documented in PAPR 2.7, 13.7.
Currently we implement no such error logic. Fix this by handling
these error cases as PAPR defines.
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
When a device is hotplugged, attach() sets "configured" to
false, waiting an action from the OS to configure it and then
to call ibm,configure-connector. On ibm,configure-connector,
the hypervisor sets "configured" to true.
In case of coldplugged device, attach() sets "configured" to
false, but firmware and OS never call the ibm,configure-connector
in this case, so it remains set to false.
It could be harmless, but when we unplug a device, hypervisor
waits the device becomes configured because for it, a not configured
device is a device being configured, so it waits the end of configuration
to unplug it... and it never happens, so it is never unplugged.
This patch set by default coldplugged device to "configured=true",
hotplugged device to "configured=false".
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The DRC_INDEX_ID_MASK macro does a left shift on ~0, which is a signed
quantity, and therefore undefined behaviour according to the C spec. In
particular this causes warnings from the clang sanitizer.
This fixes it by calculating the same mask without using ~0 (I think the
new method is a more common idiom for generating masks anyway). For good
measure I also use 1ULL to force the expression's type to unsigned long
long, which should be good for assigning to anything we're going to want
to.
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
This function handles generation of ibm,drc-* array device tree
properties to describe DRC topology to guests. This will by used
by the guest to direct RTAS calls to manage any dynamic resources
we associate with a particular DR Connector as part of
hotplug/unplug.
Since general management of boot-time device trees are handled
outside of sPAPRDRConnector, we insert these values blindly given
an FDT and offset. A mask of sPAPRDRConnector types is given to
instruct us on what types of connectors entries should be generated
for, since descriptions for different connectors may live in
different parts of the device tree.
Based on code originally written by Nathan Fontenot.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
This device emulates a firmware abstraction used by pSeries guests to
manage hotplug/dynamic-reconfiguration of host-bridges, PCI devices,
memory, and CPUs. It is conceptually similar to an SHPC device,
complete with LED indicators to identify individual slots to physical
physical users and indicate when it is safe to remove a device. In
some cases it is also used to manage virtualized resources, such a
memory, CPUs, and physical-host bridges, which in the case of pSeries
guests are virtualized resources where the physical components are
managed by the host.
Guests communicate with these DR Connectors using RTAS calls,
generally by addressing the unique DRC index associated with a
particular connector for a particular resource. For introspection
purposes we expose this state initially as QOM properties, and
in subsequent patches will introduce the RTAS calls that make use of
it. This constitutes to the 'guest' interface.
On the QEMU side we provide an attach/detach interface to associate
or cleanup a DeviceState with a particular sPAPRDRConnector in
response to hotplug/unplug, respectively. This constitutes the
'physical' interface to the DR Connector.
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
