diff options
| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2018-09-26 09:23:51 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-10-17 00:29:56 +0200 |
| commit | 9d6105b2b59fbe899eb07ff03d3993ba910f8b85 (patch) | |
| tree | bb96ac553aae78ae614bec2d5d45fc385bcd3823 /arch/x86/kvm/vmx.c | |
| parent | 09abe32002665f97e61b42af0a045080663e9e7d (diff) | |
KVM: nVMX: initialize vmcs02 constant exactly once (per VMCS)
Add a dedicated flag to track if vmcs02 has been initialized, i.e.
the constant state for vmcs02 has been written to the backing VMCS.
The launched flag (in struct loaded_vmcs) gets cleared on logical
CPU migration to mirror hardware behavior[1], i.e. using the launched
flag to determine whether or not vmcs02 constant state needs to be
initialized results in unnecessarily re-initializing the VMCS when
migrating between logical CPUS.
[1] The active VMCS needs to be VMCLEARed before it can be migrated
to a different logical CPU. Hardware's VMCS cache is per-CPU
and is not coherent between CPUs. VMCLEAR flushes the cache so
that any dirty data is written back to memory. A side effect
of VMCLEAR is that it also clears the VMCS's internal launch
flag, which KVM must mirror because VMRESUME must be used to
run a previously launched VMCS.
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index aa35ab9643ac..90e2d683a680 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -833,6 +833,13 @@ struct nested_vmx { bool sync_shadow_vmcs; bool dirty_vmcs12; + /* + * vmcs02 has been initialized, i.e. state that is constant for + * vmcs02 has been written to the backing VMCS. Initialization + * is delayed until L1 actually attempts to run a nested VM. + */ + bool vmcs02_initialized; + bool change_vmcs01_virtual_apic_mode; /* L2 must run next, and mustn't decide to exit to L1. */ @@ -8278,6 +8285,7 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu) vmx->nested.vpid02 = allocate_vpid(); + vmx->nested.vmcs02_initialized = false; vmx->nested.vmxon = true; return 0; @@ -11982,13 +11990,14 @@ static u64 nested_vmx_calc_efer(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12) static void prepare_vmcs02_constant_state(struct vcpu_vmx *vmx) { /* - * If we have never launched vmcs02, set the constant vmcs02 state + * If vmcs02 hasn't been initialized, set the constant vmcs02 state * according to L0's settings (vmcs12 is irrelevant here). Host * fields that come from L0 and are not constant, e.g. HOST_CR3, * will be set as needed prior to VMLAUNCH/VMRESUME. */ - if (vmx->nested.vmcs02.launched) + if (vmx->nested.vmcs02_initialized) return; + vmx->nested.vmcs02_initialized = true; /* All VMFUNCs are currently emulated through L0 vmexits. */ if (cpu_has_vmx_vmfunc()) |