kvm: x86: Check kvm_write_guest return value in kvm_write_wall_clock

This makes sure the wall clock is updated only after an odd version value
is successfully written to guest memory.

Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b6102c1eb3b1..102c3028513f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1169,7 +1169,8 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
 
         ++version;
 
-        kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
+        if (kvm_write_guest(kvm, wall_clock, &version, sizeof(version)))
+                return;
 
         /*
          * The guest calculates current wall clock time by adding