KVM: VMX: simplify vmx_prepare_switch_to_{guest,host}

vmx->loaded_cpu_state can only be NULL or equal to vmx->loaded_vmcs,
so change it to a bool.  Because the direction of the bool is
now the opposite of vmx->guest_msrs_dirty, change the direction of
vmx->guest_msrs_dirty so that they match.

Finally, do not imply that MSRs have to be reloaded when
vmx->guest_state_loaded is false; instead, set vmx->guest_msrs_ready
to false explicitly in vmx_prepare_switch_to_host.

Cc: Sean Christopherson <sean.j.christopherson@intel.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 0916106..02c54f6 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1057,20 +1057,18 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
         * when guest state is loaded. This happens when guest transitions
         * to/from long-mode by setting MSR_EFER.LMA.
         */
-       if (!vmx->loaded_cpu_state || vmx->guest_msrs_dirty) {
-               vmx->guest_msrs_dirty = false;
+       if (!vmx->guest_msrs_ready) {
+               vmx->guest_msrs_ready = true;
                for (i = 0; i < vmx->save_nmsrs; ++i)
                        kvm_set_shared_msr(vmx->guest_msrs[i].index,
                                           vmx->guest_msrs[i].data,
                                           vmx->guest_msrs[i].mask);
 
        }
-
-       if (vmx->loaded_cpu_state)
+       if (vmx->guest_state_loaded)
                return;
 
-       vmx->loaded_cpu_state = vmx->loaded_vmcs;
-       host_state = &vmx->loaded_cpu_state->host_state;
+       host_state = &vmx->loaded_vmcs->host_state;
 
        /*
         * Set host fs and gs selectors.  Unfortunately, 22.2.3 does not
@@ -1126,20 +1124,20 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
                vmcs_writel(HOST_GS_BASE, gs_base);
                host_state->gs_base = gs_base;
        }
+
+       vmx->guest_state_loaded = true;
 }
 
 static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx)
 {
        struct vmcs_host_state *host_state;
 
-       if (!vmx->loaded_cpu_state)
+       if (!vmx->guest_state_loaded)
                return;
 
-       WARN_ON_ONCE(vmx->loaded_cpu_state != vmx->loaded_vmcs);
-       host_state = &vmx->loaded_cpu_state->host_state;
+       host_state = &vmx->loaded_vmcs->host_state;
 
        ++vmx->vcpu.stat.host_state_reload;
-       vmx->loaded_cpu_state = NULL;
 
 #ifdef CONFIG_X86_64
        rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
@@ -1165,13 +1163,15 @@ static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx)
        wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
 #endif
        load_fixmap_gdt(raw_smp_processor_id());
+       vmx->guest_state_loaded = false;
+       vmx->guest_msrs_ready = false;
 }
 
 #ifdef CONFIG_X86_64
 static u64 vmx_read_guest_kernel_gs_base(struct vcpu_vmx *vmx)
 {
        preempt_disable();
-       if (vmx->loaded_cpu_state)
+       if (vmx->guest_state_loaded)
                rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
        preempt_enable();
        return vmx->msr_guest_kernel_gs_base;
@@ -1180,7 +1180,7 @@ static u64 vmx_read_guest_kernel_gs_base(struct vcpu_vmx *vmx)
 static void vmx_write_guest_kernel_gs_base(struct vcpu_vmx *vmx, u64 data)
 {
        preempt_disable();
-       if (vmx->loaded_cpu_state)
+       if (vmx->guest_state_loaded)
                wrmsrl(MSR_KERNEL_GS_BASE, data);
        preempt_enable();
        vmx->msr_guest_kernel_gs_base = data;
@@ -1583,7 +1583,7 @@ static void setup_msrs(struct vcpu_vmx *vmx)
                move_msr_up(vmx, index, save_nmsrs++);
 
        vmx->save_nmsrs = save_nmsrs;
-       vmx->guest_msrs_dirty = true;
+       vmx->guest_msrs_ready = false;
 
        if (cpu_has_vmx_msr_bitmap())
                vmx_update_msr_bitmap(&vmx->vcpu);

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index f03af64..4c5c24f 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -187,13 +187,23 @@ struct vcpu_vmx {
        struct kvm_vcpu       vcpu;
        u8                    fail;
        u8                    msr_bitmap_mode;
+
+       /*
+        * If true, host state has been stored in vmx->loaded_vmcs for
+        * the CPU registers that only need to be switched when transitioning
+        * to/from the kernel, and the registers have been loaded with guest
+        * values.  If false, host state is loaded in the CPU registers
+        * and vmx->loaded_vmcs->host_state is invalid.
+        */
+       bool                  guest_state_loaded;
+
        u32                   exit_intr_info;
        u32                   idt_vectoring_info;
        ulong                 rflags;
        struct shared_msr_entry *guest_msrs;
        int                   nmsrs;
        int                   save_nmsrs;
-       bool                  guest_msrs_dirty;
+       bool                  guest_msrs_ready;
 #ifdef CONFIG_X86_64
        u64                   msr_host_kernel_gs_base;
        u64                   msr_guest_kernel_gs_base;
@@ -208,14 +218,10 @@ struct vcpu_vmx {
        /*
         * 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
-        * guest (L2), it points to a different VMCS.  loaded_cpu_state points
-        * to the VMCS whose state is loaded into the CPU registers that only
-        * need to be switched when transitioning to/from the kernel; a NULL
-        * value indicates that host state is loaded.
+        * guest (L2), it points to a different VMCS.
         */
        struct loaded_vmcs    vmcs01;
        struct loaded_vmcs   *loaded_vmcs;
-       struct loaded_vmcs   *loaded_cpu_state;
 
        struct msr_autoload {
                struct vmx_msrs guest;