diff options
| author | Mingwei Zhang <mizhang@google.com> | 2022-04-21 06:14:06 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-27 15:39:00 +0300 |
| commit | 4bbd693d9f0ac81e3b3ea97ab2201424061df96c (patch) | |
| tree | fd386db0f2ef6c65212ec671724b4d629cb0326d | |
| parent | 8b2da96904895cb9f82c64e8ee428ddb15d040da (diff) | |
| download | linux-4bbd693d9f0ac81e3b3ea97ab2201424061df96c.tar.xz | |
KVM: SVM: Flush when freeing encrypted pages even on SME_COHERENT CPUs
commit d45829b351ee6ec5f54dd55e6aca1f44fe239fe6 upstream.
Use clflush_cache_range() to flush the confidential memory when
SME_COHERENT is supported in AMD CPU. Cache flush is still needed since
SME_COHERENT only support cache invalidation at CPU side. All confidential
cache lines are still incoherent with DMA devices.
Cc: stable@vger.kerel.org
Fixes: add5e2f04541 ("KVM: SVM: Add support for the SEV-ES VMSA")
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Message-Id: <20220421031407.2516575-3-mizhang@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 134c4ea5e6ad..c8c321225061 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1990,11 +1990,14 @@ static void sev_flush_guest_memory(struct vcpu_svm *svm, void *va, unsigned long len) { /* - * If hardware enforced cache coherency for encrypted mappings of the - * same physical page is supported, nothing to do. + * If CPU enforced cache coherency for encrypted mappings of the + * same physical page is supported, use CLFLUSHOPT instead. NOTE: cache + * flush is still needed in order to work properly with DMA devices. */ - if (boot_cpu_has(X86_FEATURE_SME_COHERENT)) + if (boot_cpu_has(X86_FEATURE_SME_COHERENT)) { + clflush_cache_range(va, PAGE_SIZE); return; + } /* * If the VM Page Flush MSR is supported, use it to flush the page |