From: Jiang, Yunhong <yunhong.jiang@intel.com>
Date: Thu, 21 Jul 2016 17:36:30 +0000 (+0000)
Subject: Merge "KVM: vmx: fix underflow in TSC deadline calculation"
X-Git-Tag: colorado.1.0~26
X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?p=kvmfornfv.git;a=commitdiff_plain;h=2c4b40f9829b14aa9bf12338f39d4e93474c7c77;hp=4463d0ee0febf49c4291962c8326301e3efd27f6

Merge "KVM: vmx: fix underflow in TSC deadline calculation"
---

diff --git a/kernel/arch/x86/kvm/vmx.c b/kernel/arch/x86/kvm/vmx.c
index e378975f5..5da019be6 100644
--- a/kernel/arch/x86/kvm/vmx.c
+++ b/kernel/arch/x86/kvm/vmx.c
@@ -10663,9 +10663,9 @@ static inline int u64_shl_div_u64(u64 a, unsigned int shift,
 static int vmx_set_hv_timer(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	u64 tscl = rdtsc(), delta_tsc;
-
-	delta_tsc = guest_deadline_tsc - kvm_read_l1_tsc(vcpu, tscl);
+	u64 tscl = rdtsc();
+	u64 guest_tscl = kvm_read_l1_tsc(vcpu, tscl);
+	u64 delta_tsc = max(guest_deadline_tsc, guest_tscl) - guest_tscl;
 
 	/* Convert to host delta tsc if tsc scaling is enabled */
 	if (vcpu->arch.tsc_scaling_ratio != kvm_default_tsc_scaling_ratio &&