[Qemu-devel] [PATCH 0/2] target/i386: kvm: Fix treatment of AMD SVM in nested migration

[Liran Alon]

Hi,

This patch series aims to fix the recent patch-series that was just merged to
upstream QEMU master branch which adds support for nested migration.

The already merged patch-series was modified during merge to allow migration of 
vCPU
exposed with SVM even though kernel does not support save/restore of required 
nested state.
This was done because of considering backwards-compatability.

However, during discussion made after merge, it was realised that since QEMU 
commit
75d373ef9729 ("target-i386: Disable SVM by default in KVM mode"), an AMD vCPU 
that
is virtualized by KVM doesn't expose SVM by default, even if you use "-cpu 
host".
Therefore, it is unlikely that vCPU expose SVM CPUID flag when user is not 
running
an SVM workload inside guest.

Therefore, this patch series change code back to original intent to block 
migration
in case of vCPU exposed with SVM if kernel does not support required 
capabilities
tos ave/restore nested-state.

Regards,
-Liran