Re: [PATCH 6.12.y 2/6] KVM: SVM: Use guard(mutex) to simplify SNP vCPU state updates

[Sean Christopherson <seanjc@google.com>]

On Mon, Aug 31, 2026, Sasha Levin wrote:
> From: Sean Christopherson <seanjc@google.com>
> 
> [ Upstream commit 5279d6f7e43d9c5863411482943200bf5ab8a261 ]
> 
> Use guard(mutex) in sev_snp_init_protected_guest_state() and pull in its
> lock-protected inner helper.  Without an unlock trampoline (and even with
> one), there is no real need for an inner helper.  Eliminating the helper
> also avoids having to fixup the open coded "lockdep" WARN_ON().
> 
> Opportunistically drop the error message if KVM can't obtain the pfn for
> the new target VMSA.  The error message provides zero information that
> can't be gleaned from the fact that the vCPU is stuck.
> 
> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> Link: https://lore.kernel.org/r/20250227012541.3234589-10-seanjc@google.com
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> 
> [ This tree lacks upstream commit 1fbee5b01a0fd ("KVM: guest_memfd:
>   Provide "struct page" as output from kvm_gmem_get_pfn()"), so its
>   kvm_gmem_get_pfn() still uses the older pfn-only signature (no
>   struct page **).  Adapted the refactored
>   sev_snp_init_protected_guest_state() to keep calling
>   kvm_gmem_get_pfn() without a page argument and to use
>   kvm_release_pfn_clean(pfn) instead of kvm_release_page_clean(page). ]
> 
> Stable-dep-of: 42a39ad5d592 ("KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests")
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---

Acked-by: Sean Christopherson <seanjc@google.com>