Re: [PATCH Part2 RFC v4 26/40] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command

[Brijesh Singh]

On 7/19/21 11:54 AM, Sean Christopherson wrote:
> > As I said in previous comments that by default all the memory is in the
> > hypervisor state. if the rmpupdate() failed that means nothing is changed in
> > the RMP and there is no need to reclaim. The reclaim is required only if the
> > pages are assigned in the RMP table.
>
> I wasn't referring to RMPUPDATE failing here (or anywhere).  This is the vCPU free
> path, which I think means the svm->vmsa page was successfully updated in the RMP
> during LAUNCH_UPDATE.  snp_launch_update_vmsa() goes through snp_page_reclaim()
> on LAUNCH_UPDATE failure, whereas this happy path does not.  Is there some other
> transition during teardown that obviastes the need for reclaim?  If so, a comment
> to explain that would be very helpful.

In this patch, the sev_free_vcpu() hunk takes care of reclaiming the 
vmsa pages before releasing it. I think it will make it more obvious 
after I add a helper so that we don't depend on user reading the comment 
block to see what its doing.

-Brijesh