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 <a...@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

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