[PATCH] i386: Fix KVM_CAP_ADJUST_CLOCK capability check

[Vitaly Kuznetsov]

KVM commit c68dc1b577ea ("KVM: x86: Report host tsc and realtime values in
KVM_GET_CLOCK") broke migration of certain workloads, e.g. Win11 + WSL2
guest reboots immediately after migration. KVM, however, is not to
blame this time. When KVM_CAP_ADJUST_CLOCK capability is checked, the
result is all supported flags (which the above mentioned KVM commit
enhanced) but kvm_has_adjust_clock_stable() wants it to be
KVM_CLOCK_TSC_STABLE precisely. The result is that 'clock_is_reliable'
is not set in vmstate and the saved clock reading is discarded in
kvmclock_vm_state_change().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 target/i386/kvm/kvm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index a1fd1f53791d..c33192a87dcb 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -157,7 +157,7 @@ bool kvm_has_adjust_clock_stable(void)
 {
     int ret = kvm_check_extension(kvm_state, KVM_CAP_ADJUST_CLOCK);
 
-    return (ret == KVM_CLOCK_TSC_STABLE);
+    return ret & KVM_CLOCK_TSC_STABLE;
 }
 
 bool kvm_has_adjust_clock(void)
-- 
2.37.3