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| author | Sean Christopherson <seanjc@google.com> | 2026-05-29 20:35:36 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2026-06-03 16:43:55 +0200 |
| commit | 17d62e0b157f262dd8c7586cb882ece72a5b10c2 (patch) | |
| tree | 72f7b005eff1acb436715d0de03c3ea75fbdedcc | |
| parent | e43ffb69e0438cddd72aaa30898b4dc446f664f8 (diff) | |
| download | linux-17d62e0b157f262dd8c7586cb882ece72a5b10c2.tar.gz linux-17d62e0b157f262dd8c7586cb882ece72a5b10c2.zip | |
KVM: SEV: Make it more obvious when KVM is writing back the current PSC index
Increment the guest-visible "cur_entry" index outside of the for-loop
when processing Page State Change entries, and add a comment to make it
more obvious which code is operating on trusted data, and which code is
touching guest-accessible data.
No functional change intended.
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20260529183549.1104619-12-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 62b5befe0eed..1982d13e71d9 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3947,7 +3947,7 @@ next_range: } /* Find the start of the next range which needs processing. */ - for (idx = idx_start; idx <= idx_end; idx++, hdr->cur_entry++) { + for (idx = idx_start; idx <= idx_end; idx++) { entry_start = READ_ONCE(entries[idx]); gfn = entry_start.gfn; @@ -3974,6 +3974,14 @@ next_range: if (npages) break; + + /* + * Increment the guest-visible index to communicate the current + * entry back to the guest, e.g. in case of failure. No need + * for READ_ONCE() as KVM doesn't consume the field, i.e. a + * misbehaving guest can only break itself. + */ + hdr->cur_entry++; } if (idx > idx_end) { |