Re: [PATCH v10 00/28] KVM: Enable FRED support with KVM VMX

[H. Peter Anvin]

On 2026-09-14 23:03, Xin Li wrote:
> 
>> On Sep 11, 2026, at 2:36 PM, Sohil Mehta <sohil.mehta@xxxxxxxxx> wrote:
>>
>> I mainly rebased the patches to the latest kvm-x86/next branch and fixed
>> a handful of issues reported during internal testing and basic AI
>> reviews. I've avoided making any major code changes or commit message
>> updates as this is the first iteration that I am posting. 
> 
> Thanks a lot for taking care of the patch series.
> 
>>
>> Going forward, based on the feedback, I'll rework the patches as needed.
>> I've listed a few opens below that need additional discussion or
>> clarification. I'm relatively new to the KVM subsystem, so please feel
>> free to provide suggestions on the series structure, code organization
>> as well as commit log clarity to smoothen the review process.
> 
> I’ve been thinking about an optimization: because FRED drops most of the old    
> syscall MSRs (IA32_LSTAR/IA32_CSTAR/IA32_SFMASK), we should be able to omit     
> them from KVM's uret MSR tracking entirely as if host enables FRED (no matter   
> whether a guest uses FRED).
> 
Yes, although they will need to be handled properly between VCPU switches, of
course.

	-hpa