Re: [PATCH 0/2] KVM: nVMX: vmcs.SYSENTER optimization and "fix"

[Paolo Bonzini]

On 29/04/20 01:10, Sean Christopherson wrote:
> Patch 1 is a "fix" for handling SYSENTER_EIP/ESP in L2 on a 32-bit vCPU.
> The primary motivation is to provide consistent behavior after patch 2.
> 
> Patch 2 is essentially a re-submission of a nested VMX optimization to
> avoid redundant VMREADs to the SYSENTER fields in the nested VM-Exit path.
> 
> After patch 2 and without patch 1, KVM would end up with weird behavior
> where L1 and L2 would only see 32-bit values for their own SYSENTER_E*P
> MSRs, but L1 could see a 64-bit value for L2's MSRs.
> 
> Sean Christopherson (2):
>   KVM: nVMX: Truncate writes to vmcs.SYSENTER_EIP/ESP for 32-bit vCPU
>   KVM: nVMX: Drop superfluous VMREAD of vmcs02.GUEST_SYSENTER_*
> 
>  arch/x86/kvm/vmx/nested.c |  4 ----
>  arch/x86/kvm/vmx/vmx.c    | 18 ++++++++++++++++--
>  2 files changed, 16 insertions(+), 6 deletions(-)
> 

Queued, thanks.

Paolo