Re: [PATCH v1 2/6] KVM: x86: Virtualize CR4.LASS

From: Zeng Guang
Date: Wed Jun 28 2023 - 05:27:23 EST



On 6/28/2023 1:43 AM, Sean Christopherson wrote:
On Thu, Jun 01, 2023, Zeng Guang wrote:
Virtualize CR4.LASS[bit 27] under KVM control instead of being guest-owned
as CR4.LASS generally set once for each vCPU at boot time and won't be
toggled at runtime. Besides, only if VM has LASS capability enumerated with
CPUID.(EAX=07H.ECX=1):EAX.LASS[bit 6], KVM allows guest software to be able
to set CR4.LASS.

Updating cr4_fixed1 to set CR4.LASS bit in the emulated IA32_VMX_CR4_FIXED1
MSR for guests and allow guests to enable LASS in nested VMX operaion as well.
s/operaion/operation.
Will fix in next version. Thanks.