| Message ID | 20240329225835.400662-25-michael.roth@amd.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On 3/29/24 23:58, Michael Roth wrote: > From: Ashish Kalra <ashish.kalra@amd.com> > > 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> > [mdr: Add some clarifications in commit] > Signed-off-by: Michael Roth <michael.roth@amd.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/svm/sev.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 31f6f4786503..3e8de7cb3c89 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -2975,7 +2975,14 @@ 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 should be > + * unreachable via the hva-based mmu notifiers. Additionally, > + * for shared->private translations, H/W coherency will ensure > + * first guest access to the page would clear out any existing > + * dirty copies of that cacheline. > + */ > + if (!sev_guest(kvm) || sev_snp_guest(kvm)) > return; > > wbinvd_on_all_cpus();
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 31f6f4786503..3e8de7cb3c89 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2975,7 +2975,14 @@ 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 should be + * unreachable via the hva-based mmu notifiers. Additionally, + * for shared->private translations, H/W coherency will ensure + * first guest access to the page would clear out any existing + * dirty copies of that cacheline. + */ + if (!sev_guest(kvm) || sev_snp_guest(kvm)) return; wbinvd_on_all_cpus();