[PATCH 5.14 056/172] KVM: SEV: Pin guest memory for write for RECEIVE_UPDATE_DATA

Greg Kroah-Hartman
2021-10-04T13:32:20Z

From: Sean Christopherson <seanjc@google.com>

commit 50c038018d6be20361e8a2890262746a4ac5b11f upstream.

Require the target guest page to be writable when pinning memory for
RECEIVE_UPDATE_DATA. Per the SEV API, the PSP writes to guest memory:

The result is then encrypted with GCTX.VEK and written to the memory
pointed to by GUEST_PADDR field.

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: Sean Christopherson <seanjc@google.com>
Message-Id: <20210914210951.2994260-2-seanjc@google.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/svm/sev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1465,7 +1465,7 @@ static int sev_receive_update_data(struc

/* Pin guest memory */
guest_page = sev_pin_memory(kvm, params.guest_uaddr & PAGE_MASK,
- PAGE_SIZE, &n, 0);
+ PAGE_SIZE, &n, 1);
if (IS_ERR(guest_page)) {
ret = PTR_ERR(guest_page);
goto e_free_trans;