The mpx feature was removed from the corresponding qemu cpu models.
With mpx in the libvirt cpu models, libvirt believes the feature
to be implicitly enabled when creating qemu VMs, while in fact it is
disabled.
This became an issue when commit 94eacd5a5f introduced new vmx-*
features, of which some are dependent on mpx (see "feature_dependencies"
table in qemu target/i386/cpu.c), e.g. vmx-exit-clear-bndcfgs and
vmx-entry-load-bndcfgs. These features cannot be enabled by qemu
without also mpx being enabled, leading to the error message
error: Failed to create domain from testdomain.xml
error: operation failed: guest CPU doesn't match
specification: missing features: mpx,vmx-exit-clear-bndcfgs,
vmx-entry-load-bndcfgs
when trying to create a VM with a "host-model" cpu on a host that
does support mpx and the mentioned vmx-* features:
<domain>
...
<cpu mode='host-model' check='full' />
...
</domain>
Resolve the issue by removing mpx from libvirt's cpu models as well.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The default number of CPU clusters is 1, and values other than
that one are currently rejected by all hypervisor drivers.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Differences from qemu:
* "vmx-ept-uc" (bit 8) and "vmx-ept-wb" (bit 14) are not added to
qemu's list of named features yet, but used in several qemu cpu
models never the less. Add to libvirt regardless.
* "vmx-invvpid-single-context" (bit 41) is erroneously called
"vmx-invept-single-context" in qemu. This is the name of the
feature associated with bit 25 in both libvirt and qemu.
* "vmx-invvpid-single-context-noglobals" (bit 43) is erroneously
called "vmx-invept-single-context-noglobals". Use the correct name.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Fix the syntax-check failures (which can be seen after
python3-flake8-import-order package is installed) with the help
of isort[1]:
289/316 libvirt:syntax-check / flake8 FAIL 5.24s exit status 2
[1]: https://pycqa.github.io/isort/
Signed-off-by: Han Han <hhan@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Commit 10b5e789c5 attempts to filter out the logical processor id
in the generated data to remove noise and irrelevant changes in the
output.
cpuid-leaf 0x0B may have more than two sub-leaves though. Filter out
logical processor id from all sub-leaves of 0x0B and 0x1F (superset
of the information in 0x0B).
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
cpu-data.py assumes that all "feature" nodes have exactly one child.
This assumption will no longer be true when the cpumap includes alias-
names for features.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Commit 5c17a7ba41 introduced a new feature (ibrs) but did not update
existing cputestdata.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Internally we already collect x86 host family + model + stepping
numeric values. This exposed them in capabilities CPU output.
Example:
$ sudo virsh capabilities | grep -A1 -B1 signature
<microcode version='240'/>
<signature family='6' model='94' stepping='3'/>
<counter name='tsc' frequency='3408010000' scaling='no'/>
Users need to know these values to calculate an expected.
SEV-ES/SEV-SNP launch measurement.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
While we don't want to aim for the shortest list of disabled features in
the baseline result (it would select a very old model), we want to do so
while looking at any of the input models for which we're trying to
compute a baseline CPU model. Given a set of input models, we always
want to take the least capable one of them (i.e., the one with shortest
list of disabled features) or a better model which is not one of the
input models.
So when considering an input model, we just check whether its list of
disabled features is shorter than the currently best one. When looking
at other models we check both enabled and disabled features while
penalizing disabled features as implemented by the previous patch.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
For finding the best matching CPU model for a given set of features
while we don't know the CPU signature (i.e., when computing a baseline
CPU model) we've been using a "shortest list of features" heuristics.
This works well if new CPU models are supersets of older models, but
that's not always the case. As a result it may actually select a new CPU
model as a baseline while removing some features from it to make it
compatible with older models. This is in general worse than using an old
CPU model with a bunch of added features as a guest OS or apps may crash
when using features that were disabled.
On the other hand we don't want to end up with a very old model which
would guarantee no disabled features as it could stop a guest OS or apps
from using some features provided by the CPU because they would not
expect them on such an old CPU.
This patch changes the heuristics to something in between. Enabled and
disabled features are counted separately so that a CPU model requiring
some features to be disabled looks worse than a model with fewer
disabled features even if its complete list of features is longer. The
penalty given for each additional disabled feature gets bigger to make
longer list of disabled features look even worse.
https://bugzilla.redhat.com/show_bug.cgi?id=1851227
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
These ancient RHEL-only CPU models should not really be used by any CPU
definition created by libvirt. We keep them just for backwards
compatibility with domains which might still be using them.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Reporting hv-* properties properly requires hv to be enabled,
see qemu commit 071ce4b03b.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Linux 5.13 introduces "kcpuid", a tool similar to "cpuid", see
https://lore.kernel.org/lkml/1614928878-86075-1-git-send-email-feng.tang@intel.com/
Output formats of cpuid and kcpuid differ slightly. This adds support
for the latter.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
As explained in QEMU commit 4c257911dcc7c4189768e9651755c849ce9db4e8
intel-pt features should never be included in the CPU models as it was
not supported by KVM back then and even once it started to be supported,
users have to enable it by passing pt_mode=1 parameter to kvm_intel
module. The Icelake-* CPU models with intel-pt included were added to
QEMU 3.1.0 and removed right in the following 4.0.0 release (and even in
3.1.1 maintenance release).
In libvirt 6.10.0 I introduced 'removed' attribute for features included
in our CPU model definitions which we can use to drop intel-pt from
Icelake-* CPU models. Back then I explained we can safely do so only for
features which could never be enabled, which is not the case of intel-pt.
Theoretically, it could be possible to create an environment in which
QEMU would enable intel-pt without asking for it explicitly: it would
need to use a new enough kernel (not available at the time of QEMU
3.1.0) and pt_mode KVM parameter in combination with QEMU 3.1.0 running
a domain with q35 machine type and all that on a CPU which didn't really
exist at that time.
Migrating such domain to a host with newer SW stack including libvirt
with this patch applied would result in incompatible guest ABI (the
virtual CPU would lose intel-pt). However, QEMU changed its CPU models
unconditionally and thus migration would not work even without this
patch. That said, it is safe to follow QEMU and remove the feature from
Icelake-* CPU models in our cpu_map.
https://bugzilla.redhat.com/show_bug.cgi?id=1853972
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Tim Wiederhake <twiederh@redhat.com>
The output of cpuid depends on the logical processor id the process
runs on, as reflected by the "local apic id" present in cpuid leaves
(eax=1,ebx=0), (eax=11,ebx=0), and (eax=11,ebx=1). This produces
arbitrary changes in the output files that complicate comparisons.
This patch masks the occurences of the local apic id with 0x00, so
that two consecutive runs of "./cpu-data.py gather" produce identical
results.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
It is now doing way more than gathering the CPU data from a host as the
other scripts were merged in it.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Due to missing pdpe1gb support in the host CPU data, the CPU is still
incorrectly detected as Westmere-IBRS for host capabilities because we
don't have the option to disable features included in the base model
there.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
It's obvious the CPU model detection provides strange results, which
will be fixed by adding a new Snowridge CPU model few patches later.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
This allows for the functionality of cpu-cpuid.py script to be
integrated more naturally in a later patch.
Changes the way this script should be called:
cpu-gather.py -> cpu-gather.py
cpu-gather.py --gather -> cpu-gather.py gather
cpu-gather.py --parse -> cpu-gather.py parse
cpu-gather.py --gather --parse -> cpu-gather.py full
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Prepare to deduplicate the list of relevant registers for cpuid and
msr information.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Prepare to deduplicate the list of relevant registers for cpuid and
msr information.
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
