Guest CPU definitions with mode='custom' and missing <vendor> are
expected to run on a host CPU from any vendor as long as the required
CPU model can be used as a guest CPU on the host. But even though no CPU
vendor was explicitly requested we would sometimes force it due to a bug
in virCPUUpdate and virCPUTranslate.
The bug would effectively forbid cross vendor migrations even if they
were previously working just fine.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
The API is no longer used anywhere else since it was replaced by a much
saner work flow utilizing new APIs that work on virCPUDefPtr directly:
virCPUCompare, virCPUUpdate, and virCPUTranslate.
Not testing the new work flow caused some bugs to be hidden. This patch
reveals them, but doesn't attempt to fix them. To make sure all test
still pass after this patch, all affected test results are modified to
pretend the tests succeeded. All of the bugs will be fixed in the
following commits and the artificial modifications will be reverted.
The following is the list of bugs in the new CPU model work flow:
- a guest CPU with mode='custom' and missing <vendor/> gets the vendor
copied from host's CPU (the vendor should only be copied to host-model
CPUs):
DO_TEST_UPDATE("x86", "host", "min", VIR_CPU_COMPARE_IDENTICAL)
DO_TEST_UPDATE("x86", "host", "pentium3", VIR_CPU_COMPARE_IDENTICAL)
DO_TEST_GUESTCPU("x86", "host-better", "pentium3", NULL, 0)
- when a guest CPU with mode='custom' needs to be translated into
another model because the original model is not supported by a
hypervisor, the result will have its vendor set to the vendor of the
original CPU model as specified in cpu_map.xml even if the original
guest CPU XML didn't contain <vendor/>:
DO_TEST_GUESTCPU("x86", "host", "guest", model486, 0)
DO_TEST_GUESTCPU("x86", "host", "guest", models, 0)
DO_TEST_GUESTCPU("x86", "host-Haswell-noTSX", "Haswell-noTSX",
haswell, 0)
- legacy POWERx_v* model names are not recognized:
DO_TEST_GUESTCPU("ppc64", "host", "guest-legacy", ppc_models, 0)
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
In some cases preferred model doesn't really do anything since the
result remains the same even if it is removed.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Using a preferred CPU model which is not in the list of CPU models
supported by a hypervisor does not make sense.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Guest CPUs with match='minimum' should always be updated to match host
CPU model. Trying to get different results by supplying preferred models
does not make sense.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
The reworked API is now called virCPUUpdate and it should change the
provided CPU definition into a one which can be consumed by the QEMU
command line builder:
- host-passthrough remains unchanged
- host-model is turned into custom CPU with a model and features
copied from host
- custom CPU with minimum match is converted similarly to host-model
- optional features are updated according to host's CPU
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Some Intel processor families (e.g. the Intel Xeon processor E5 v3
family) introduced some PQos (Platform Qos) features, including CMT
(Cache Monitoring technology) and MBM (Memory Bandwidth Monitoring),
to monitor or control shared resource. This patch add them into x86
part of cpu_map.xml to be used for applications based on libvirt to
get cpu capabilities. For example, Nova in OpenStack schedules guests
based on the CPU features that the host has.
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Our current detection code uses just the number of CPU features which
need to be added/removed from the CPU model to fully describe the CPUID
data. The smallest number wins. But this may sometimes generate wrong
results as one can see from the fixed test cases. This patch modifies
the algorithm to prefer the CPU model with matching signature even if
this model results in a longer list of additional features.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
The CPU model was implemented in QEMU by commit f6f949e929.
The change to i7-5600U is wrong since it's a 5th generation CPU, i.e.,
Broadwell rather than Skylake, but that's just the result of our CPU
detection code (which is fixed by the following commit).
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
The actual CPU model in the data files is Penryn which makes the file
name look rather strange. Well, one of them contains Nehalem, but that's
a bug which will be fixed soon.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
As a side effect this changes the order of CPU features in XMLs
generated by libvirt, but that's not a big deal since the order there is
insignificant.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
So far we only test CPUID -> CPU def conversion on artificial CPUID data
computed from another CPU def. This patch adds the infrastructure to
test this conversion on real data gathered from a host CPU and two
helper scripts for adding new test data:
- cpu-gather.sh runs cpuid tool and qemu-system-x86_64 to get CPUID data
from the host CPU; this is what users can be asked to run if they run
into an issue with host CPU detection in libvirt
- cpu-parse.sh takes the data generated by cpu-gather.sh and creates
data files for CPU detection tests
The CPUID data queried from QEMU will eventually switch to the format
used by query-host-cpu QMP command once QEMU implements it. Until then
we just spawn QEMU with -cpu host and query the guest CPU in QOM. They
should both provide the same CPUID results, but query-host-cpu does not
require any guest CPU to be created by QEMU.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
When computing CPU data for a given guest CPU we should set CPUID vendor
bits appropriately so that we don't lose the vendor when transforming
CPU data back to XML description.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
There's no reason for keeping the features in a linked list. Especially
when we know upfront the total number of features we are loading.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Limitations of the POWER architecture mean that you can't run
eg. a POWER7 guest on a POWER8 host when using KVM. This applies
to all guests, not just those using VIR_CPU_MATCH_STRICT in the
CPU definition; in fact, exact and strict CPU matching are
basically the same on ppc64.
This means, of course, that hosts using different CPUs have to be
considered incompatible as well.
Change ppc64Compute(), called by cpuGuestData(), to reflect this
fact and update test cases accordingly.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1250977
