This patch contains the following two changes:
1. Fix the bug in nested preemption timer support. If vmexit L2->L0
with some reasons not emulated by L1, preemption timer value should
be save in such exits.
2. Add support of "Save VMX-preemption timer value" VM-Exit controls
to nVMX.
With this patch, nested VMX preemption timer features are fully
supported.
Signed-off-by: Arthur Chunqi Li <yzt356@xxxxxxxxx>
---
arch/x86/kvm/vmx.c | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 57b4e12..9579409 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2204,7 +2204,8 @@ static __init void nested_vmx_setup_ctls_msrs(void)
#ifdef CONFIG_X86_64
VM_EXIT_HOST_ADDR_SPACE_SIZE |
#endif
- VM_EXIT_LOAD_IA32_PAT | VM_EXIT_SAVE_IA32_PAT;
+ VM_EXIT_LOAD_IA32_PAT | VM_EXIT_SAVE_IA32_PAT |
+ VM_EXIT_SAVE_VMX_PREEMPTION_TIMER;
nested_vmx_exit_ctls_high |= (VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR |
VM_EXIT_LOAD_IA32_EFER);
@@ -7578,9 +7579,14 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
(vmcs_config.pin_based_exec_ctrl |
vmcs12->pin_based_vm_exec_control));
- if (vmcs12->pin_based_vm_exec_control & PIN_BASED_VMX_PREEMPTION_TIMER)
- vmcs_write32(VMX_PREEMPTION_TIMER_VALUE,
- vmcs12->vmx_preemption_timer_value);
+ if (vmcs12->pin_based_vm_exec_control & PIN_BASED_VMX_PREEMPTION_TIMER) {
+ if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER)
+ vmcs12->vmx_preemption_timer_value =
+ vmcs_read32(VMX_PREEMPTION_TIMER_VALUE);
+ else
+ vmcs_write32(VMX_PREEMPTION_TIMER_VALUE,
+ vmcs12->vmx_preemption_timer_value);
+ }
/*
* Whether page-faults are trapped is determined by a combination of
@@ -7690,7 +7696,11 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
* we should use its exit controls. Note that VM_EXIT_LOAD_IA32_EFER
* bits are further modified by vmx_set_efer() below.
*/
- vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl);
+ if (vmcs12->pin_based_vm_exec_control & PIN_BASED_VMX_PREEMPTION_TIMER)
+ vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl |
+ VM_EXIT_SAVE_VMX_PREEMPTION_TIMER);
+ else
+ vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl);
/* vmcs12's VM_ENTRY_LOAD_IA32_EFER and VM_ENTRY_IA32E_MODE are
* emulated by vmx_set_efer(), below.
@@ -7912,6 +7922,16 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
}
/*
+ * If L2 support PIN_BASED_VMX_PREEMPTION_TIMER, L0 must support
+ * VM_EXIT_SAVE_VMX_PREEMPTION_TIMER.
+ */
+ if ((vmcs12->pin_based_vm_exec_control & PIN_BASED_VMX_PREEMPTION_TIMER) &&
+ !(nested_vmx_exit_ctls_high & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER)) {
+ nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
+ return 1;
+ }
+
+ /*
* We're finally done with prerequisite checking, and can start with
* the nested entry.
*/
--
1.7.9.5
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