path: root/arch/x86/kvm/svm
diff options
authorMasahiro Kozuka <masa.koz@kozuka.jp>2021-09-14 14:09:51 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2021-10-21 13:01:25 -0400
commitc8c340a9b4149fe5caa433f3b62463a1c8e07a46 (patch)
treeee3ab9a43c294ec0a53cd00fcb51df0092b312ee /arch/x86/kvm/svm
parenta3ca5281bb771d8103ea16f0a6a8a5df9a7fb4f3 (diff)
KVM: SEV: Flush cache on non-coherent systems before RECEIVE_UPDATE_DATA
Flush the destination page before invoking RECEIVE_UPDATE_DATA, as the PSP encrypts the data with the guest's key when writing to guest memory. If the target memory was not previously encrypted, the cache may contain dirty, unecrypted data that will persist on non-coherent systems. Fixes: 15fb7de1a7f5 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command") Cc: stable@vger.kernel.org Cc: Peter Gonda <pgonda@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Masahiro Kozuka <masa.koz@kozuka.jp> [sean: converted bug report to changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210914210951.2994260-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm')
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 0d21d59936e5..2e4916be290e 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1484,6 +1484,13 @@ static int sev_receive_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
goto e_free_trans;
+ /*
+ * Flush (on non-coherent CPUs) before RECEIVE_UPDATE_DATA, the PSP
+ * encrypts the written data with the guest's key, and the cache may
+ * contain dirty, unencrypted data.
+ */
+ sev_clflush_pages(guest_page, n);
/* The RECEIVE_UPDATE_DATA command requires C-bit to be always set. */
data.guest_address = (page_to_pfn(guest_page[0]) << PAGE_SHIFT) + offset;
data.guest_address |= sev_me_mask;