Commit 9446e6fc authored Feb 12, 2020 by Paolo Bonzini

KVM: x86: fix WARN_ON check of an unsigned less than zero



The check cpu->hv_clock.system_time < 0 is redundant since system_time
is a u64 and hence can never be less than zero.  But what was actually
meant is to check that the result is positive, since kernel_ns and
v->kvm->arch.kvmclock_offset are both s64.

Reported-by: Colin King <colin.king@canonical.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Addresses-Coverity: ("Macro compares unsigned to 0")
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent ff479025

arch/x86/kvm/x86.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2444,7 +2444,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
		vcpu->hv_clock.tsc_timestamp = tsc_timestamp;
		vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
		vcpu->last_guest_tsc = tsc_timestamp;
		WARN_ON(vcpu->hv_clock.system_time < 0);
		WARN_ON((s64)vcpu->hv_clock.system_time < 0);

		/* If the host uses TSC clocksource, then it is stable */
		pvclock_flags = 0;

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