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KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP

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With SNP/guest_memfd, private/encrypted memory should not be mappable,
and MMU notifications for HVA-mapped memory will only be relevant to
unencrypted guest memory. Therefore, the rationale behind issuing a
wbinvd_on_all_cpus() in sev_guest_memory_reclaimed() should not apply
for SNP guests and can be ignored.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
[mdr: Add some clarifications in commit]
Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-ID: <20240501085210.2213060-17-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ashish Kalra
2024-05-01 03:52:06 -05:00
committed by Paolo Bonzini
parent b2104024f4
commit ea262f8a7c
1 changed files with 7 additions and 1 deletions
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8
arch/x86/kvm/svm/sev.c
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@@ -3039,7 +3039,13 @@ do_wbinvd:
void sev_guest_memory_reclaimed(struct kvm *kvm)
{
if (!sev_guest(kvm))
/*
* With SNP+gmem, private/encrypted memory is unreachable via the
* hva-based mmu notifiers, so these events are only actually
* pertaining to shared pages where there is no need to perform
* the WBINVD to flush associated caches.
*/
if (!sev_guest(kvm) || sev_snp_guest(kvm))
return;
wbinvd_on_all_cpus();