KVM: VMX: shadow VM_(ENTRY|EXIT)_CONTROLS vmcs field

VM_(ENTRY|EXIT)_CONTROLS vmcs fields are read/written on each guest
entry but most times it can be avoided since values do not changes.
Keep fields copy in memory to avoid unnecessary reads from vmcs.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 85 insertions, 27 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b2fe1c252f35..1024689ac717 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -418,6 +418,8 @@ struct vcpu_vmx {
         u64                   msr_host_kernel_gs_base;
         u64                   msr_guest_kernel_gs_base;
 #endif
+        u32 vm_entry_controls_shadow;
+        u32 vm_exit_controls_shadow;
         /*
          * loaded_vmcs points to the VMCS currently used in this vcpu. For a
          * non-nested (L1) guest, it always points to vmcs01. For a nested
@@ -1326,6 +1328,62 @@ static void vmcs_set_bits(unsigned long field, u32 mask)
         vmcs_writel(field, vmcs_readl(field) | mask);
 }
 
+static inline void vm_entry_controls_init(struct vcpu_vmx *vmx, u32 val)
+{
+        vmcs_write32(VM_ENTRY_CONTROLS, val);
+        vmx->vm_entry_controls_shadow = val;
+}
+
+static inline void vm_entry_controls_set(struct vcpu_vmx *vmx, u32 val)
+{
+        if (vmx->vm_entry_controls_shadow != val)
+                vm_entry_controls_init(vmx, val);
+}
+
+static inline u32 vm_entry_controls_get(struct vcpu_vmx *vmx)
+{
+        return vmx->vm_entry_controls_shadow;
+}
+
+
+static inline void vm_entry_controls_setbit(struct vcpu_vmx *vmx, u32 val)
+{
+        vm_entry_controls_set(vmx, vm_entry_controls_get(vmx) | val);
+}
+
+static inline void vm_entry_controls_clearbit(struct vcpu_vmx *vmx, u32 val)
+{
+        vm_entry_controls_set(vmx, vm_entry_controls_get(vmx) & ~val);
+}
+
+static inline void vm_exit_controls_init(struct vcpu_vmx *vmx, u32 val)
+{
+        vmcs_write32(VM_EXIT_CONTROLS, val);
+        vmx->vm_exit_controls_shadow = val;
+}
+
+static inline void vm_exit_controls_set(struct vcpu_vmx *vmx, u32 val)
+{
+        if (vmx->vm_exit_controls_shadow != val)
+                vm_exit_controls_init(vmx, val);
+}
+
+static inline u32 vm_exit_controls_get(struct vcpu_vmx *vmx)
+{
+        return vmx->vm_exit_controls_shadow;
+}
+
+
+static inline void vm_exit_controls_setbit(struct vcpu_vmx *vmx, u32 val)
+{
+        vm_exit_controls_set(vmx, vm_exit_controls_get(vmx) | val);
+}
+
+static inline void vm_exit_controls_clearbit(struct vcpu_vmx *vmx, u32 val)
+{
+        vm_exit_controls_set(vmx, vm_exit_controls_get(vmx) & ~val);
+}
+
 static void vmx_segment_cache_clear(struct vcpu_vmx *vmx)
 {
         vmx->segment_cache.bitmask = 0;
@@ -1410,11 +1468,11 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
         vmcs_write32(EXCEPTION_BITMAP, eb);
 }
 
-static void clear_atomic_switch_msr_special(unsigned long entry,
-                unsigned long exit)
+static void clear_atomic_switch_msr_special(struct vcpu_vmx *vmx,
+                unsigned long entry, unsigned long exit)
 {
-        vmcs_clear_bits(VM_ENTRY_CONTROLS, entry);
-        vmcs_clear_bits(VM_EXIT_CONTROLS, exit);
+        vm_entry_controls_clearbit(vmx, entry);
+        vm_exit_controls_clearbit(vmx, exit);
 }
 
 static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
@@ -1425,14 +1483,15 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
         switch (msr) {
         case MSR_EFER:
                 if (cpu_has_load_ia32_efer) {
-                        clear_atomic_switch_msr_special(VM_ENTRY_LOAD_IA32_EFER,
+                        clear_atomic_switch_msr_special(vmx,
+                                        VM_ENTRY_LOAD_IA32_EFER,
                                         VM_EXIT_LOAD_IA32_EFER);
                         return;
                 }
                 break;
         case MSR_CORE_PERF_GLOBAL_CTRL:
                 if (cpu_has_load_perf_global_ctrl) {
-                        clear_atomic_switch_msr_special(
+                        clear_atomic_switch_msr_special(vmx,
                                         VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL,
                                         VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL);
                         return;
@@ -1453,14 +1512,15 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
         vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr);
 }
 
-static void add_atomic_switch_msr_special(unsigned long entry,
-                unsigned long exit, unsigned long guest_val_vmcs,
-                unsigned long host_val_vmcs, u64 guest_val, u64 host_val)
+static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,
+                unsigned long entry, unsigned long exit,
+                unsigned long guest_val_vmcs, unsigned long host_val_vmcs,
+                u64 guest_val, u64 host_val)
 {
         vmcs_write64(guest_val_vmcs, guest_val);
         vmcs_write64(host_val_vmcs, host_val);
-        vmcs_set_bits(VM_ENTRY_CONTROLS, entry);
-        vmcs_set_bits(VM_EXIT_CONTROLS, exit);
+        vm_entry_controls_setbit(vmx, entry);
+        vm_exit_controls_setbit(vmx, exit);
 }
 
 static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
@@ -1472,7 +1532,8 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
         switch (msr) {
         case MSR_EFER:
                 if (cpu_has_load_ia32_efer) {
-                        add_atomic_switch_msr_special(VM_ENTRY_LOAD_IA32_EFER,
+                        add_atomic_switch_msr_special(vmx,
+                                        VM_ENTRY_LOAD_IA32_EFER,
                                         VM_EXIT_LOAD_IA32_EFER,
                                         GUEST_IA32_EFER,
                                         HOST_IA32_EFER,
@@ -1482,7 +1543,7 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
                 break;
         case MSR_CORE_PERF_GLOBAL_CTRL:
                 if (cpu_has_load_perf_global_ctrl) {
-                        add_atomic_switch_msr_special(
+                        add_atomic_switch_msr_special(vmx,
                                         VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL,
                                         VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL,
                                         GUEST_IA32_PERF_GLOBAL_CTRL,
@@ -3182,14 +3243,10 @@ static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
         vmx_load_host_state(to_vmx(vcpu));
         vcpu->arch.efer = efer;
         if (efer & EFER_LMA) {
-                vmcs_write32(VM_ENTRY_CONTROLS,
-                             vmcs_read32(VM_ENTRY_CONTROLS) |
-                             VM_ENTRY_IA32E_MODE);
+                vm_entry_controls_setbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
                 msr->data = efer;
         } else {
-                vmcs_write32(VM_ENTRY_CONTROLS,
-                             vmcs_read32(VM_ENTRY_CONTROLS) &
-                             ~VM_ENTRY_IA32E_MODE);
+                vm_entry_controls_clearbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
 
                 msr->data = efer & ~EFER_LME;
         }
@@ -3217,9 +3274,7 @@ static void enter_lmode(struct kvm_vcpu *vcpu)
 
 static void exit_lmode(struct kvm_vcpu *vcpu)
 {
-        vmcs_write32(VM_ENTRY_CONTROLS,
-                     vmcs_read32(VM_ENTRY_CONTROLS)
-                     & ~VM_ENTRY_IA32E_MODE);
+        vm_entry_controls_clearbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
         vmx_set_efer(vcpu, vcpu->arch.efer & ~EFER_LMA);
 }
 
@@ -4346,10 +4401,11 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
                 ++vmx->nmsrs;
         }
 
-        vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl);
+
+        vm_exit_controls_init(vmx, vmcs_config.vmexit_ctrl);
 
         /* 22.2.1, 20.8.1 */
-        vmcs_write32(VM_ENTRY_CONTROLS, vmcs_config.vmentry_ctrl);
+        vm_entry_controls_init(vmx, vmcs_config.vmentry_ctrl);
 
         vmcs_writel(CR0_GUEST_HOST_MASK, ~0UL);
         set_cr4_guest_host_mask(vmx);
@@ -7759,12 +7815,12 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
         exit_control = vmcs_config.vmexit_ctrl;
         if (vmcs12->pin_based_vm_exec_control & PIN_BASED_VMX_PREEMPTION_TIMER)
                 exit_control |= VM_EXIT_SAVE_VMX_PREEMPTION_TIMER;
-        vmcs_write32(VM_EXIT_CONTROLS, exit_control);
+        vm_exit_controls_init(vmx, exit_control);
 
         /* vmcs12's VM_ENTRY_LOAD_IA32_EFER and VM_ENTRY_IA32E_MODE are
          * emulated by vmx_set_efer(), below.
          */
-        vmcs_write32(VM_ENTRY_CONTROLS,
+        vm_entry_controls_init(vmx, 
                 (vmcs12->vm_entry_controls & ~VM_ENTRY_LOAD_IA32_EFER &
                         ~VM_ENTRY_IA32E_MODE) |
                 (vmcs_config.vmentry_ctrl & ~VM_ENTRY_IA32E_MODE));
@@ -8186,7 +8242,7 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 
         vmcs12->vm_entry_controls =
                 (vmcs12->vm_entry_controls & ~VM_ENTRY_IA32E_MODE) |
-                (vmcs_read32(VM_ENTRY_CONTROLS) & VM_ENTRY_IA32E_MODE);
+                (vm_entry_controls_get(to_vmx(vcpu)) & VM_ENTRY_IA32E_MODE);
 
         /* TODO: These cannot have changed unless we have MSR bitmaps and
          * the relevant bit asks not to trap the change */
@@ -8390,6 +8446,8 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu)
         vcpu->cpu = cpu;
         put_cpu();
 
+        vm_entry_controls_init(vmx, vmcs_read32(VM_ENTRY_CONTROLS));
+        vm_exit_controls_init(vmx, vmcs_read32(VM_EXIT_CONTROLS));
         vmx_segment_cache_clear(vmx);
 
         /* if no vmcs02 cache requested, remove the one we used */