[PATCH 1/3] KVM: VMX: Cache CPU_BASED_VM_EXEC_CONTROL VMCS field

[Avi Kivity <avi@redhat.com>]

The CPU_BASED_VM_EXEC_CONTROL VMCS field is write-only, so we can cache it
in the vcpu structure and avoid a costly vmcs_read32() every time we want
to change a bit.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/vmx.c |   60 +++++++++++++++++++++++++--------------------------
 1 files changed, 29 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f76137c..ee1cd1a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -130,6 +130,7 @@ struct vcpu_vmx {
 	u8                    fail;
 	u32                   exit_intr_info;
 	u32                   idt_vectoring_info;
+	u32                   cpu_based_vm_exec_control;
 	struct shared_msr_entry *guest_msrs;
 	int                   nmsrs;
 	int                   save_nmsrs;
@@ -643,6 +644,18 @@ static void vmcs_set_bits(unsigned long field, u32 mask)
 	vmcs_writel(field, vmcs_readl(field) | mask);
 }
 
+static void set_cpu_based_vm_exec_ctrl_bits(struct vcpu_vmx *vmx, u32 mask)
+{
+	vmx->cpu_based_vm_exec_control |= mask;
+	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, vmx->cpu_based_vm_exec_control);
+}
+
+static void clear_cpu_based_vm_exec_ctrl_bits(struct vcpu_vmx *vmx, u32 mask)
+{
+	vmx->cpu_based_vm_exec_control &= ~mask;
+	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, vmx->cpu_based_vm_exec_control);
+}
+
 static void update_exception_bitmap(struct kvm_vcpu *vcpu)
 {
 	u32 eb;
@@ -1932,18 +1945,16 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
 	vmx_decache_cr3(vcpu);
 	if (!(cr0 & X86_CR0_PG)) {
 		/* From paging/starting to nonpaging */
-		vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
-			     vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) |
-			     (CPU_BASED_CR3_LOAD_EXITING |
-			      CPU_BASED_CR3_STORE_EXITING));
+		set_cpu_based_vm_exec_ctrl_bits(to_vmx(vcpu),
+						CPU_BASED_CR3_LOAD_EXITING |
+						CPU_BASED_CR3_STORE_EXITING);
 		vcpu->arch.cr0 = cr0;
 		vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
 	} else if (!is_paging(vcpu)) {
 		/* From nonpaging to paging */
-		vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
-			     vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) &
-			     ~(CPU_BASED_CR3_LOAD_EXITING |
-			       CPU_BASED_CR3_STORE_EXITING));
+		clear_cpu_based_vm_exec_ctrl_bits(to_vmx(vcpu),
+						  CPU_BASED_CR3_LOAD_EXITING |
+						  CPU_BASED_CR3_STORE_EXITING);
 		vcpu->arch.cr0 = cr0;
 		vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
 	}
@@ -2622,6 +2633,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 		exec_control |= CPU_BASED_CR3_STORE_EXITING |
 				CPU_BASED_CR3_LOAD_EXITING  |
 				CPU_BASED_INVLPG_EXITING;
+	vmx->cpu_based_vm_exec_control = exec_control;
 	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, exec_control);
 
 	if (cpu_has_secondary_exec_ctrls()) {
@@ -2873,17 +2885,12 @@ out:
 
 static void enable_irq_window(struct kvm_vcpu *vcpu)
 {
-	u32 cpu_based_vm_exec_control;
-
-	cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
-	cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_INTR_PENDING;
-	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
+	set_cpu_based_vm_exec_ctrl_bits(to_vmx(vcpu),
+					CPU_BASED_VIRTUAL_INTR_PENDING);
 }
 
 static void enable_nmi_window(struct kvm_vcpu *vcpu)
 {
-	u32 cpu_based_vm_exec_control;
-
 	if (!cpu_has_virtual_nmis()) {
 		enable_irq_window(vcpu);
 		return;
@@ -2893,9 +2900,8 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu)
 		enable_irq_window(vcpu);
 		return;
 	}
-	cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
-	cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_NMI_PENDING;
-	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
+	set_cpu_based_vm_exec_ctrl_bits(to_vmx(vcpu),
+					CPU_BASED_VIRTUAL_NMI_PENDING);
 }
 
 static void vmx_inject_irq(struct kvm_vcpu *vcpu)
@@ -3408,13 +3414,9 @@ static int handle_tpr_below_threshold(struct kvm_vcpu *vcpu)
 
 static int handle_interrupt_window(struct kvm_vcpu *vcpu)
 {
-	u32 cpu_based_vm_exec_control;
-
 	/* clear pending irq */
-	cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
-	cpu_based_vm_exec_control &= ~CPU_BASED_VIRTUAL_INTR_PENDING;
-	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
-
+	clear_cpu_based_vm_exec_ctrl_bits(to_vmx(vcpu),
+					  CPU_BASED_VIRTUAL_INTR_PENDING);
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 
 	++vcpu->stat.irq_window_exits;
@@ -3671,12 +3673,8 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
 
 static int handle_nmi_window(struct kvm_vcpu *vcpu)
 {
-	u32 cpu_based_vm_exec_control;
-
-	/* clear pending NMI */
-	cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
-	cpu_based_vm_exec_control &= ~CPU_BASED_VIRTUAL_NMI_PENDING;
-	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
+	clear_cpu_based_vm_exec_ctrl_bits(to_vmx(vcpu),
+					  CPU_BASED_VIRTUAL_NMI_PENDING);
 	++vcpu->stat.nmi_window_exits;
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 
@@ -3691,7 +3689,7 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
 	u32 cpu_exec_ctrl;
 	bool intr_window_requested;
 
-	cpu_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
+	cpu_exec_ctrl = vmx->cpu_based_vm_exec_control;
 	intr_window_requested = cpu_exec_ctrl & CPU_BASED_VIRTUAL_INTR_PENDING;
 
 	while (!guest_state_valid(vcpu)) {
-- 
1.7.1