Maxim,
On 5/3/22 12:13 AM, Maxim Levitsky wrote:
In the kvm/queue branch, I found a regression on nested SVM guest, where L2 guest cannot
launch. The bad commit is:
commit a4cfff3f0f8c07f1f7873a82bdeb3995807dac8c (bisect)
Merge: 42dcbe7d8bac 8d5678a76689
Author: Paolo Bonzini<pbonzini@xxxxxxxxxx>
Date: Fri Apr 8 12:43:40 2022 -0400
Merge branch 'kvm-older-features' into HEAD
Merge branch for features that did not make it into 5.18:
* New ioctls to get/set TSC frequency for a whole VM
* Allow userspace to opt out of hypercall patching
Nested virtualization improvements for AMD:
* Support for "nested nested" optimizations (nested vVMLOAD/VMSAVE,
nested vGIF)
* Allow AVIC to co-exist with a nested guest running
* Fixes for LBR virtualizations when a nested guest is running,
and nested LBR virtualization support
* PAUSE filtering for nested hypervisors
Guest support:
* Decoupling of vcpu_is_preempted from PV spinlocks
Signed-off-by: Paolo Bonzini<pbonzini@xxxxxxxxxx>
I am still working on the bisect into the merge commits.
Regards,
Suravee
What happens when the guest can't launch? It sure works for me for kvm/queue
from yesterday.
I'll test again tomorrow.
I have bisected it to this commit:
commit 74fd41ed16fd71725e69e2cb90b755505326c2e6
Author: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Date: Tue Mar 22 19:40:47 2022 +0200
KVM: x86: nSVM: support PAUSE filtering when L0 doesn't intercept PAUSE
Expose the pause filtering and threshold in the guest CPUID
and support PAUSE filtering when possible:
- If the L0 doesn't intercept PAUSE (cpu_pm=on), then allow L1 to
have full control over PAUSE filtering.
- if the L1 doesn't intercept PAUSE, use host values and update
the adaptive count/threshold even when running nested.
- Otherwise always exit to L1; it is not really possible to merge
the fields correctly. It is expected that in this case, userspace
will not enable this feature in the guest CPUID, to avoid having the
guest update both fields pointlessly.
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Message-Id: <20220322174050.241850-4-mlevitsk@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
I can revert this one or specify pause_filter_count=0 pause_filter_thresh=0,
and then I can boot the L2 guest.
Regards,
Suravee
