Commit ea262f8a authored by Ashish Kalra's avatar Ashish Kalra Committed by Paolo Bonzini
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KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP 



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: default avatarAshish Kalra <ashish.kalra@amd.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
[mdr: Add some clarifications in commit]
Signed-off-by: default avatarMichael Roth <michael.roth@amd.com>
Message-ID: <20240501085210.2213060-17-michael.roth@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b2104024

arch/x86/kvm/svm/sev.c

+7 −1
Original line number Diff line number Diff line
@@ -3039,7 +3039,13 @@ static void sev_flush_encrypted_page(struct kvm_vcpu *vcpu, void *va) 


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();