Commit ee5a5584 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: VMX: Invert handling of CR0.WP for EPT without unrestricted guest 



Opt-in to forcing CR0.WP=1 for shadow paging, and stop lying about WP
being "always on" for unrestricted guest.  In addition to making KVM a
wee bit more honest, this paves the way for additional cleanup.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-22-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9e90e215

arch/x86/kvm/vmx/vmx.c

+5 −9
Original line number Diff line number Diff line
@@ -136,8 +136,7 @@ module_param(allow_smaller_maxphyaddr, bool, S_IRUGO); 
#define KVM_VM_CR0_ALWAYS_OFF (X86_CR0_NW | X86_CR0_CD)

#define KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST X86_CR0_NE

#define KVM_VM_CR0_ALWAYS_ON				\

	(KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST | 	\

	 X86_CR0_WP | X86_CR0_PG | X86_CR0_PE)

	(KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST | X86_CR0_PG | X86_CR0_PE)



#define KVM_VM_CR4_ALWAYS_ON_UNRESTRICTED_GUEST X86_CR4_VMXE

#define KVM_PMODE_VM_CR4_ALWAYS_ON (X86_CR4_PAE | X86_CR4_VMXE)
@@ -2995,9 +2994,7 @@ void ept_save_pdptrs(struct kvm_vcpu *vcpu) 
	kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);

}



static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,

					unsigned long cr0,

					struct kvm_vcpu *vcpu)

static void ept_update_paging_mode_cr0(unsigned long cr0, struct kvm_vcpu *vcpu)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -3016,9 +3013,6 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0, 
		vcpu->arch.cr0 = cr0;

		vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));

	}



	if (!(cr0 & X86_CR0_WP))

		*hw_cr0 &= ~X86_CR0_WP;

}



void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
@@ -3031,6 +3025,8 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
		hw_cr0 |= KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST;

	else {

		hw_cr0 |= KVM_VM_CR0_ALWAYS_ON;

		if (!enable_ept)

			hw_cr0 |= X86_CR0_WP;



		if (vmx->rmode.vm86_active && (cr0 & X86_CR0_PE))

			enter_pmode(vcpu);
@@ -3049,7 +3045,7 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
#endif



	if (enable_ept && !is_unrestricted_guest(vcpu))

		ept_update_paging_mode_cr0(&hw_cr0, cr0, vcpu);

		ept_update_paging_mode_cr0(cr0, vcpu);



	vmcs_writel(CR0_READ_SHADOW, cr0);

	vmcs_writel(GUEST_CR0, hw_cr0);