1 files changed, 32 insertions, 29 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4655d6dd6759..62670b2f6d48 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -397,6 +397,7 @@ struct loaded_vmcs {
         int cpu;
         bool launched;
         bool nmi_known_unmasked;
+        bool hv_timer_armed;
         /* Support for vnmi-less CPUs */
         int soft_vnmi_blocked;
         ktime_t entry_time;
@@ -10595,24 +10596,38 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx)
                                         msrs[i].host, false);
 }
 
-static void vmx_arm_hv_timer(struct kvm_vcpu *vcpu)
+static void vmx_arm_hv_timer(struct vcpu_vmx *vmx, u32 val)
+{
+        vmcs_write32(VMX_PREEMPTION_TIMER_VALUE, val);
+        if (!vmx->loaded_vmcs->hv_timer_armed)
+                vmcs_set_bits(PIN_BASED_VM_EXEC_CONTROL,
+                              PIN_BASED_VMX_PREEMPTION_TIMER);
+        vmx->loaded_vmcs->hv_timer_armed = true;
+}
+
+static void vmx_update_hv_timer(struct kvm_vcpu *vcpu)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
         u64 tscl;
         u32 delta_tsc;
 
-        if (vmx->hv_deadline_tsc == -1)
-                return;
+        if (vmx->hv_deadline_tsc != -1) {
+                tscl = rdtsc();
+                if (vmx->hv_deadline_tsc > tscl)
+                        /* set_hv_timer ensures the delta fits in 32-bits */
+                        delta_tsc = (u32)((vmx->hv_deadline_tsc - tscl) >>
+                                cpu_preemption_timer_multi);
+                else
+                        delta_tsc = 0;
 
-        tscl = rdtsc();
-        if (vmx->hv_deadline_tsc > tscl)
-                /* sure to be 32 bit only because checked on set_hv_timer */
-                delta_tsc = (u32)((vmx->hv_deadline_tsc - tscl) >>
-                        cpu_preemption_timer_multi);
-        else
-                delta_tsc = 0;
+                vmx_arm_hv_timer(vmx, delta_tsc);
+                return;
+        }
 
-        vmcs_write32(VMX_PREEMPTION_TIMER_VALUE, delta_tsc);
+        if (vmx->loaded_vmcs->hv_timer_armed)
+                vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL,
+                                PIN_BASED_VMX_PREEMPTION_TIMER);
+        vmx->loaded_vmcs->hv_timer_armed = false;
 }
 
 static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
@@ -10672,7 +10687,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
         atomic_switch_perf_msrs(vmx);
 
-        vmx_arm_hv_timer(vcpu);
+        vmx_update_hv_timer(vcpu);
 
         /*
          * If this vCPU has touched SPEC_CTRL, restore the guest's value if
@@ -12078,11 +12093,10 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 
         exec_control = vmcs12->pin_based_vm_exec_control;
 
-        /* Preemption timer setting is only taken from vmcs01.  */
-        exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
+        /* Preemption timer setting is computed directly in vmx_vcpu_run.  */
         exec_control |= vmcs_config.pin_based_exec_ctrl;
-        if (vmx->hv_deadline_tsc == -1)
-                exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
+        exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
+        vmx->loaded_vmcs->hv_timer_armed = false;
 
         /* Posted interrupts setting is only taken from vmcs12.  */
         if (nested_cpu_has_posted_intr(vmcs12)) {
@@ -13255,12 +13269,7 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
         vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr);
         vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
         vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset);
-        if (vmx->hv_deadline_tsc == -1)
-                vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL,
-                                PIN_BASED_VMX_PREEMPTION_TIMER);
-        else
-                vmcs_set_bits(PIN_BASED_VM_EXEC_CONTROL,
-                              PIN_BASED_VMX_PREEMPTION_TIMER);
+
         if (kvm_has_tsc_control)
                 decache_tsc_multiplier(vmx);
 
@@ -13464,18 +13473,12 @@ static int vmx_set_hv_timer(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc)
                 return -ERANGE;
 
         vmx->hv_deadline_tsc = tscl + delta_tsc;
-        vmcs_set_bits(PIN_BASED_VM_EXEC_CONTROL,
-                        PIN_BASED_VMX_PREEMPTION_TIMER);
-
         return delta_tsc == 0;
 }
 
 static void vmx_cancel_hv_timer(struct kvm_vcpu *vcpu)
 {
-        struct vcpu_vmx *vmx = to_vmx(vcpu);
-        vmx->hv_deadline_tsc = -1;
-        vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL,
-                        PIN_BASED_VMX_PREEMPTION_TIMER);
+        to_vmx(vcpu)->hv_deadline_tsc = -1;
 }
 #endif