diff mbox series

KVM: x86/xen: Use a safer data type for delta to avoid shift-count-overflow

Message ID 20220309064324.58213-1-likexu@tencent.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86/xen: Use a safer data type for delta to avoid shift-count-overflow | expand

Commit Message

Like Xu March 9, 2022, 6:43 a.m. UTC 
From: Like Xu <likexu@tencent.com>

Clang warns:

arch/x86/kvm/xen.c:1219:41: warning: right shift count >= width of type [-Wshift-count-overflow]
 1219 |         (delta > 0 && (uint32_t) (delta >> 50) != 0))) {
      |                                         ^~

The delta is long, which is 32-bit on ARCH=i386, hence the overflow
warning. Switch to uint64_t, which is 64-bit and will not overflow.

Fixes: 49c0b9159bce ("KVM: x86/xen: handle PV timers oneshot mode")
Signed-off-by: Like Xu <likexu@tencent.com>
---
 arch/x86/kvm/xen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 8c85a71aa8ca..097181613be5 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -1204,7 +1204,7 @@  static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
 
 	if (timeout) {
 		uint64_t guest_now = get_kvmclock_ns(vcpu->kvm);
-		long delta = timeout - guest_now;
+		uint64_t delta = timeout - guest_now;
 
 		/* Xen has a 'Linux workaround' in do_set_timer_op() which
 		 * checks for negative absolute timeout values (caused by