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Commit 44ea2b17 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: VMX: Move MSR_KERNEL_GS_BASE out of the vmx autoload msr area 



Currently MSR_KERNEL_GS_BASE is saved and restored as part of the
guest/host msr reloading.  Since we wish to lazy-restore all the other
msrs, save and reload MSR_KERNEL_GS_BASE explicitly instead of using
the common code.

Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 3ce672d4

arch/x86/kvm/vmx.c

+26 −13
Original line number Diff line number Diff line
@@ -99,7 +99,8 @@ struct vcpu_vmx { 
	int                   save_nmsrs;

	int                   msr_offset_efer;

#ifdef CONFIG_X86_64

	int                   msr_offset_kernel_gs_base;

	u64 		      msr_host_kernel_gs_base;

	u64 		      msr_guest_kernel_gs_base;

#endif

	struct vmcs          *vmcs;

	struct {
@@ -202,7 +203,7 @@ static void ept_save_pdptrs(struct kvm_vcpu *vcpu); 
 */

static const u32 vmx_msr_index[] = {

#ifdef CONFIG_X86_64

	MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR, MSR_KERNEL_GS_BASE,

	MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR,

#endif

	MSR_EFER, MSR_K6_STAR,

};
@@ -674,10 +675,10 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu) 
#endif



#ifdef CONFIG_X86_64

	if (is_long_mode(&vmx->vcpu))

		save_msrs(vmx->host_msrs +

			  vmx->msr_offset_kernel_gs_base, 1);



	if (is_long_mode(&vmx->vcpu)) {

		rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);

		wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);

	}

#endif

	load_msrs(vmx->guest_msrs, vmx->save_nmsrs);

	load_transition_efer(vmx);
@@ -711,6 +712,12 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) 
	save_msrs(vmx->guest_msrs, vmx->save_nmsrs);

	load_msrs(vmx->host_msrs, vmx->save_nmsrs);

	reload_host_efer(vmx);

#ifdef CONFIG_X86_64

	if (is_long_mode(&vmx->vcpu)) {

		rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);

		wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);

	}

#endif

}



static void vmx_load_host_state(struct vcpu_vmx *vmx)
@@ -938,9 +945,6 @@ static void setup_msrs(struct vcpu_vmx *vmx) 
		if (index >= 0)

			move_msr_up(vmx, index, save_nmsrs++);

		index = __find_msr_index(vmx, MSR_CSTAR);

		if (index >= 0)

			move_msr_up(vmx, index, save_nmsrs++);

		index = __find_msr_index(vmx, MSR_KERNEL_GS_BASE);

		if (index >= 0)

			move_msr_up(vmx, index, save_nmsrs++);

		/*
@@ -954,10 +958,6 @@ static void setup_msrs(struct vcpu_vmx *vmx) 
#endif

	vmx->save_nmsrs = save_nmsrs;



#ifdef CONFIG_X86_64

	vmx->msr_offset_kernel_gs_base =

		__find_msr_index(vmx, MSR_KERNEL_GS_BASE);

#endif

	vmx->msr_offset_efer = __find_msr_index(vmx, MSR_EFER);



	if (cpu_has_vmx_msr_bitmap()) {
@@ -1015,6 +1015,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata) 
	case MSR_GS_BASE:

		data = vmcs_readl(GUEST_GS_BASE);

		break;

	case MSR_KERNEL_GS_BASE:

		vmx_load_host_state(to_vmx(vcpu));

		data = to_vmx(vcpu)->msr_guest_kernel_gs_base;

		break;

	case MSR_EFER:

		return kvm_get_msr_common(vcpu, msr_index, pdata);

#endif
@@ -1068,6 +1072,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) 
	case MSR_GS_BASE:

		vmcs_writel(GUEST_GS_BASE, data);

		break;

	case MSR_KERNEL_GS_BASE:

		vmx_load_host_state(vmx);

		vmx->msr_guest_kernel_gs_base = data;

		break;

#endif

	case MSR_IA32_SYSENTER_CS:

		vmcs_write32(GUEST_SYSENTER_CS, data);
@@ -1559,6 +1567,11 @@ static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer) 
	struct vcpu_vmx *vmx = to_vmx(vcpu);

	struct kvm_msr_entry *msr = find_msr_entry(vmx, MSR_EFER);



	/*

	 * Force kernel_gs_base reloading before EFER changes, as control

	 * of this msr depends on is_long_mode().

	 */

	vmx_load_host_state(to_vmx(vcpu));

	vcpu->arch.shadow_efer = efer;

	if (!msr)

		return;