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Commit aff48baa authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: Fetch guest cr3 from hardware on demand 



Instead of syncing the guest cr3 every exit, which is expensince on vmx
with ept enabled, sync it only on demand.

[sheng: fix incorrect cr3 seen by Windows XP]

Signed-off-by: default avatarSheng Yang <sheng@linux.intel.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 9f8fe504

arch/x86/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ enum kvm_reg { 


enum kvm_reg_ex {

	VCPU_EXREG_PDPTR = NR_VCPU_REGS,

	VCPU_EXREG_CR3,

};



enum {
@@ -533,6 +534,7 @@ struct kvm_x86_ops { 
			    struct kvm_segment *var, int seg);

	void (*get_cs_db_l_bits)(struct kvm_vcpu *vcpu, int *db, int *l);

	void (*decache_cr0_guest_bits)(struct kvm_vcpu *vcpu);

	void (*decache_cr3)(struct kvm_vcpu *vcpu);

	void (*decache_cr4_guest_bits)(struct kvm_vcpu *vcpu);

	void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);

	void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);

arch/x86/kvm/kvm_cache_regs.h

+2 −0
Original line number Diff line number Diff line
@@ -75,6 +75,8 @@ static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask) 


static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu)

{

	if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail))

		kvm_x86_ops->decache_cr3(vcpu);

	return vcpu->arch.cr3;

}

arch/x86/kvm/svm.c

+5 −0
Original line number Diff line number Diff line
@@ -1327,6 +1327,10 @@ static void svm_decache_cr0_guest_bits(struct kvm_vcpu *vcpu) 
{

}



static void svm_decache_cr3(struct kvm_vcpu *vcpu)

{

}



static void svm_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)

{

}
@@ -3871,6 +3875,7 @@ static struct kvm_x86_ops svm_x86_ops = { 
	.get_cpl = svm_get_cpl,

	.get_cs_db_l_bits = kvm_get_cs_db_l_bits,

	.decache_cr0_guest_bits = svm_decache_cr0_guest_bits,

	.decache_cr3 = svm_decache_cr3,

	.decache_cr4_guest_bits = svm_decache_cr4_guest_bits,

	.set_cr0 = svm_set_cr0,

	.set_cr3 = svm_set_cr3,

arch/x86/kvm/vmx.c

+12 −6
Original line number Diff line number Diff line
@@ -180,6 +180,7 @@ static int init_rmode(struct kvm *kvm); 
static u64 construct_eptp(unsigned long root_hpa);

static void kvm_cpu_vmxon(u64 addr);

static void kvm_cpu_vmxoff(void);

static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);



static DEFINE_PER_CPU(struct vmcs *, vmxarea);

static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -1866,6 +1867,13 @@ static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu) 
	vcpu->arch.cr0 |= vmcs_readl(GUEST_CR0) & cr0_guest_owned_bits;

}



static void vmx_decache_cr3(struct kvm_vcpu *vcpu)

{

	if (enable_ept && is_paging(vcpu))

		vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);

	__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);

}



static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)

{

	ulong cr4_guest_owned_bits = vcpu->arch.cr4_guest_owned_bits;
@@ -1909,6 +1917,7 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0, 
					unsigned long cr0,

					struct kvm_vcpu *vcpu)

{

	vmx_decache_cr3(vcpu);

	if (!(cr0 & X86_CR0_PG)) {

		/* From paging/starting to nonpaging */

		vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
@@ -3756,11 +3765,6 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) 
	if (vmx->emulation_required && emulate_invalid_guest_state)

		return handle_invalid_guest_state(vcpu);



	/* Access CR3 don't cause VMExit in paging mode, so we need

	 * to sync with guest real CR3. */

	if (enable_ept && is_paging(vcpu))

		vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);



	if (exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) {

		vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;

		vcpu->run->fail_entry.hardware_entry_failure_reason
@@ -4077,7 +4081,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) 
	      );



	vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP)

				  | (1 << VCPU_EXREG_PDPTR));

				  | (1 << VCPU_EXREG_PDPTR)

				  | (1 << VCPU_EXREG_CR3));

	vcpu->arch.regs_dirty = 0;



	vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
@@ -4344,6 +4349,7 @@ static struct kvm_x86_ops vmx_x86_ops = { 
	.get_cpl = vmx_get_cpl,

	.get_cs_db_l_bits = vmx_get_cs_db_l_bits,

	.decache_cr0_guest_bits = vmx_decache_cr0_guest_bits,

	.decache_cr3 = vmx_decache_cr3,

	.decache_cr4_guest_bits = vmx_decache_cr4_guest_bits,

	.set_cr0 = vmx_set_cr0,

	.set_cr3 = vmx_set_cr3,

arch/x86/kvm/x86.c

+2 −0
Original line number Diff line number Diff line
@@ -667,6 +667,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) 
	if (unlikely(!gfn_to_memslot(vcpu->kvm, cr3 >> PAGE_SHIFT)))

		return 1;

	vcpu->arch.cr3 = cr3;

	__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);

	vcpu->arch.mmu.new_cr3(vcpu);

	return 0;

}
@@ -5583,6 +5584,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, 
	vcpu->arch.cr2 = sregs->cr2;

	mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3;

	vcpu->arch.cr3 = sregs->cr3;

	__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);



	kvm_set_cr8(vcpu, sregs->cr8);