Commit 34059c25 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86: Fold decache_cr3() into cache_reg() 



Handle caching CR3 (from VMX's VMCS) into struct kvm_vcpu via the common
cache_reg() callback and drop the dedicated decache_cr3().  The name
decache_cr3() is somewhat confusing as the caching behavior of CR3
follows that of GPRs, RFLAGS and PDPTRs, (handled via cache_reg()), and
has nothing in common with the caching behavior of CR0/CR4 (whose
decache_cr{0,4}_guest_bits() likely provided the 'decache' verbiage).

This would effectivel adds a BUG() if KVM attempts to cache CR3 on SVM.
Change it to a WARN_ON_ONCE() -- if the cache never requires filling,
the value is already in the right place -- and opportunistically add one
in VMX to provide an equivalent check.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent cb3c1e2f

arch/x86/include/asm/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -1033,7 +1033,6 @@ 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

+1 −1
Original line number Diff line number Diff line
@@ -137,7 +137,7 @@ static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask) 
static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu)

{

	if (!kvm_register_is_available(vcpu, VCPU_EXREG_CR3))

		kvm_x86_ops->decache_cr3(vcpu);

		kvm_x86_ops->cache_reg(vcpu, VCPU_EXREG_CR3);

	return vcpu->arch.cr3;

}

arch/x86/kvm/svm.c

+1 −6
Original line number Diff line number Diff line
@@ -2376,7 +2376,7 @@ static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg) 
		load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));

		break;

	default:

		BUG();

		WARN_ON_ONCE(1);

	}

}
@@ -2529,10 +2529,6 @@ 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)

{

}
@@ -7269,7 +7265,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = { 
	.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/vmx.c

+6 −9
Original line number Diff line number Diff line
@@ -2192,7 +2192,12 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg) 
		if (enable_ept)

			ept_save_pdptrs(vcpu);

		break;

	case VCPU_EXREG_CR3:

		if (enable_unrestricted_guest || (enable_ept && is_paging(vcpu)))

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

		break;

	default:

		WARN_ON_ONCE(1);

		break;

	}

}
@@ -2863,13 +2868,6 @@ 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_unrestricted_guest || (enable_ept && is_paging(vcpu)))

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

	kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);

}



static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)

{

	ulong cr4_guest_owned_bits = vcpu->arch.cr4_guest_owned_bits;
@@ -2914,7 +2912,7 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0, 
	struct vcpu_vmx *vmx = to_vmx(vcpu);



	if (!kvm_register_is_available(vcpu, VCPU_EXREG_CR3))

		vmx_decache_cr3(vcpu);

		vmx_cache_reg(vcpu, VCPU_EXREG_CR3);

	if (!(cr0 & X86_CR0_PG)) {

		/* From paging/starting to nonpaging */

		exec_controls_setbit(vmx, CPU_BASED_CR3_LOAD_EXITING |
@@ -7784,7 +7782,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { 
	.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,