[PATCH 2/2] KVM: nVMX: Skip IPBP when switching between vmcs01 and vmcs02, redux

From: Sean Christopherson
Date: Wed May 06 2020 - 19:58:53 EST


Skip the Indirect Branch Prediction Barrier that is triggered on a VMCS
switch when temporarily loading vmcs02 to synchronize it to vmcs12, i.e.
give copy_vmcs02_to_vmcs12_rare() the same treatment as
vmx_switch_vmcs().

Make vmx_vcpu_load() static now that it's only referenced within vmx.c.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 4 ++--
arch/x86/kvm/vmx/vmx.c | 2 +-
arch/x86/kvm/vmx/vmx.h | 1 -
3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 7d1e19149ef46..4f770eed66cc9 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3915,12 +3915,12 @@ static void copy_vmcs02_to_vmcs12_rare(struct kvm_vcpu *vcpu,

cpu = get_cpu();
vmx->loaded_vmcs = &vmx->nested.vmcs02;
- vmx_vcpu_load(&vmx->vcpu, cpu);
+ vmx_vcpu_load_vmcs(vcpu, cpu, &vmx->vmcs01);

sync_vmcs02_to_vmcs12_rare(vcpu, vmcs12);

vmx->loaded_vmcs = &vmx->vmcs01;
- vmx_vcpu_load(&vmx->vcpu, cpu);
+ vmx_vcpu_load_vmcs(vcpu, cpu, &vmx->nested.vmcs02);
put_cpu();
}

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ddbd8fae24927..bc5e5cf1d4cc8 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1383,7 +1383,7 @@ void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu,
* Switches to specified vcpu, until a matching vcpu_put(), but assumes
* vcpu mutex is already taken.
*/
-void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 4a6f382b05b49..298ddef79d009 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -322,7 +322,6 @@ struct kvm_vmx {
bool nested_vmx_allowed(struct kvm_vcpu *vcpu);
void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu,
struct loaded_vmcs *buddy);
-void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
int allocate_vpid(void);
void free_vpid(int vpid);
void vmx_set_constant_host_state(struct vcpu_vmx *vmx);
--
2.26.0