Commit b464f57e authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 4d6c9892

arch/x86/kvm/vmx/vmx.c

+13 −13
Original line number Diff line number Diff line
@@ -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);

arch/x86/kvm/vmx/vmx.h

+12 −6
Original line number Diff line number Diff line
@@ -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;