KVM: Fix compound mmio

mmio_index should be taken into account when copying data from
userspace.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e3ac212f7c87..a9a307a75465 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5576,7 +5576,8 @@ static int complete_mmio(struct kvm_vcpu *vcpu)
         if (vcpu->mmio_needed) {
                 vcpu->mmio_needed = 0;
                 if (!vcpu->mmio_is_write)
-                        memcpy(vcpu->mmio_data, run->mmio.data, 8);
+                        memcpy(vcpu->mmio_data + vcpu->mmio_index,
+                               run->mmio.data, 8);
                 vcpu->mmio_index += 8;
                 if (vcpu->mmio_index < vcpu->mmio_size) {
                         run->exit_reason = KVM_EXIT_MMIO;