KVM: VMX: Smush x2APIC MSR bitmap adjustments into single function

Consolidate all of the dynamic MSR bitmap adjustments into
vmx_update_msr_bitmap_x2apic(), and rename the mode tracker to reflect
that it is x2APIC specific.  If KVM gains more cases of dynamic MSR
pass-through, odds are very good that those new cases will be better off
with their own logic, e.g. see Intel PT MSRs and MSR_IA32_SPEC_CTRL.

Attempting to handle all updates in a common helper did more harm than
good, as KVM ended up collecting a large number of useless "updates".

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-42-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 3088201..96d9147 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3812,21 +3812,6 @@ void vmx_enable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
                vmx_set_msr_bitmap_write(msr_bitmap, msr);
 }
 
-static u8 vmx_msr_bitmap_mode(struct kvm_vcpu *vcpu)
-{
-       u8 mode = 0;
-
-       if (cpu_has_secondary_exec_ctrls() &&
-           (secondary_exec_controls_get(to_vmx(vcpu)) &
-            SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
-               mode |= MSR_BITMAP_MODE_X2APIC;
-               if (enable_apicv && kvm_vcpu_apicv_active(vcpu))
-                       mode |= MSR_BITMAP_MODE_X2APIC_APICV;
-       }
-
-       return mode;
-}
-
 static void vmx_reset_x2apic_msrs(struct kvm_vcpu *vcpu, u8 mode)
 {
        unsigned long *msr_bitmap = to_vmx(vcpu)->vmcs01.msr_bitmap;
@@ -3844,11 +3829,29 @@ static void vmx_reset_x2apic_msrs(struct kvm_vcpu *vcpu, u8 mode)
        }
 }
 
-static void vmx_update_msr_bitmap_x2apic(struct kvm_vcpu *vcpu, u8 mode)
+static void vmx_update_msr_bitmap_x2apic(struct kvm_vcpu *vcpu)
 {
+       struct vcpu_vmx *vmx = to_vmx(vcpu);
+       u8 mode;
+
        if (!cpu_has_vmx_msr_bitmap())
                return;
 
+       if (cpu_has_secondary_exec_ctrls() &&
+           (secondary_exec_controls_get(vmx) &
+            SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
+               mode = MSR_BITMAP_MODE_X2APIC;
+               if (enable_apicv && kvm_vcpu_apicv_active(vcpu))
+                       mode |= MSR_BITMAP_MODE_X2APIC_APICV;
+       } else {
+               mode = 0;
+       }
+
+       if (mode == vmx->x2apic_msr_bitmap_mode)
+               return;
+
+       vmx->x2apic_msr_bitmap_mode = mode;
+
        vmx_reset_x2apic_msrs(vcpu, mode);
 
        /*
@@ -3865,21 +3868,6 @@ static void vmx_update_msr_bitmap_x2apic(struct kvm_vcpu *vcpu, u8 mode)
        }
 }
 
-static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu)
-{
-       struct vcpu_vmx *vmx = to_vmx(vcpu);
-       u8 mode = vmx_msr_bitmap_mode(vcpu);
-       u8 changed = mode ^ vmx->msr_bitmap_mode;
-
-       if (!changed)
-               return;
-
-       if (changed & (MSR_BITMAP_MODE_X2APIC | MSR_BITMAP_MODE_X2APIC_APICV))
-               vmx_update_msr_bitmap_x2apic(vcpu, mode);
-
-       vmx->msr_bitmap_mode = mode;
-}
-
 void pt_update_intercept_for_msr(struct kvm_vcpu *vcpu)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -4139,8 +4127,7 @@ static void vmx_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
                                        SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY);
        }
 
-       if (cpu_has_vmx_msr_bitmap())
-               vmx_update_msr_bitmap(vcpu);
+       vmx_update_msr_bitmap_x2apic(vcpu);
 }
 
 u32 vmx_exec_control(struct vcpu_vmx *vmx)
@@ -6190,7 +6177,7 @@ void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
        }
        secondary_exec_controls_set(vmx, sec_exec_control);
 
-       vmx_update_msr_bitmap(vcpu);
+       vmx_update_msr_bitmap_x2apic(vcpu);
 }
 
 static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu)

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index a408a90..0ecc411 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -227,7 +227,7 @@ struct nested_vmx {
 struct vcpu_vmx {
        struct kvm_vcpu       vcpu;
        u8                    fail;
-       u8                    msr_bitmap_mode;
+       u8                    x2apic_msr_bitmap_mode;
 
        /*
         * If true, host state has been stored in vmx->loaded_vmcs for