linux-kernel - Re: [PULL 13/19] KVM: SEV: Implement gmem hook for invalidating private pages

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Date: Tue, 21 May 2024 18:55:25 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: Michael Roth <michael.roth@....com>
Cc: Sean Christopherson <seanjc@...gle.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PULL 13/19] KVM: SEV: Implement gmem hook for invalidating
 private pages

On Thu, May 16, 2024 at 5:12 AM Michael Roth <michael.roth@....com> wrote:
> Longer term if we need something more robust would be to modify the
> .free_folio callback path to pass along folio->mapping, or switch to
> something else that provides similar functionality. Another approach
> might be to set .free_folio dynamically based on the vm_type of the
> gmem user when creating the gmem instance.

You need to not warn. Testing CC_ATTR_HOST_SEV_SNP is just an optimization.

Paolo

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index dc00b89404a2..1c57b4535f15 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4676,8 +4676,7 @@ void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)
         bool assigned;

         rc = snp_lookup_rmpentry(pfn, &assigned, &rmp_level);
-        if (WARN_ONCE(rc, "SEV: Failed to retrieve RMP entry for PFN
0x%llx error %d\n",
-                  pfn, rc))
+        if (rc)
             goto next_pfn;

         if (!assigned)

Paolo