KVM: nVMX: keep preemption timer enabled during L2 execution
Because the vmcs12 preemption timer is emulated through a separate hrtimer,
we can keep on using the preemption timer in the vmcs02 to emulare L1's
TSC deadline timer.
However, the corresponding bit in the pin-based execution control field
must be kept consistent between vmcs01 and vmcs02. On vmentry we copy
it into the vmcs02; on vmexit the preemption timer must be disabled in
the vmcs01 if a preemption timer vmexit happened while in guest mode.
The preemption timer value in the vmcs02 is set by vmx_vcpu_run, so it
need not be considered in prepare_vmcs02.
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Cc: Haozhong Zhang <haozhong.zhang@intel.com>
Tested-by: Wanpeng Li <kernellwp@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0048be7..8cda444 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9796,9 +9796,14 @@
vmcs_write64(VMCS_LINK_POINTER, -1ull);
exec_control = vmcs12->pin_based_vm_exec_control;
- exec_control |= vmcs_config.pin_based_exec_ctrl;
- exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
+ /* Preemption timer setting is only taken from vmcs01. */
+ exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
+ exec_control |= vmcs_config.pin_based_exec_ctrl;
+ if (vmx->hv_deadline_tsc == -1)
+ exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
+
+ /* Posted interrupts setting is only taken from vmcs12. */
if (nested_cpu_has_posted_intr(vmcs12)) {
/*
* Note that we use L0's vector here and in
@@ -10727,8 +10732,14 @@
load_vmcs12_host_state(vcpu, vmcs12);
- /* Update TSC_OFFSET if TSC was changed while L2 ran */
+ /* Update any VMCS fields that might have changed while L2 ran */
vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_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);
/* This is needed for same reason as it was needed in prepare_vmcs02 */
vmx->host_rsp = 0;
