[PATCH 5.14 109/169] KVM: SEV-ES: fix length of string I/O

Greg Kroah-Hartman
2021-10-25T19:54:54Z

From: Paolo Bonzini <pbonzini@redhat.com>

commit 019057bd73d1751fdfec41e43148baf3303d98f9 upstream.

The size of the data in the scratch buffer is not divided by the size of
each port I/O operation, so vcpu->arch.pio.count ends up being larger
than it should be by a factor of size.

Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Acked-by: Tom Lendacky <thomas.lendacky@amd.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
@@ -2591,7 +2591,7 @@ int sev_es_string_io(struct vcpu_svm *sv
return -EINVAL;

return kvm_sev_es_string_io(&svm->vcpu, size, port,
- svm->ghcb_sa, svm->ghcb_sa_len, in);
+ svm->ghcb_sa, svm->ghcb_sa_len / size, in);
}

void sev_es_init_vmcb(struct vcpu_svm *svm)