Commit 32437c2a authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: VMX: Process CR0.PG side effects after setting CR0 assets 



Move the long mode and EPT w/o unrestricted guest side effect processing
down in vmx_set_cr0() so that the EPT && !URG case doesn't have to stuff
vcpu->arch.cr0 early.  This also fixes an oddity where CR0 might not be
marked available, i.e. the early vcpu->arch.cr0 write would appear to be
in danger of being overwritten, though that can't actually happen in the
current code since CR0.TS is the only guest-owned bit, and CR0.TS is not
read by vmx_set_cr4().

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-28-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 908b7d43

arch/x86/kvm/vmx/vmx.c

+12 −11
Original line number Diff line number Diff line
@@ -3003,9 +3003,11 @@ void ept_save_pdptrs(struct kvm_vcpu *vcpu) 
void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);

	unsigned long hw_cr0;

	unsigned long hw_cr0, old_cr0_pg;

	u32 tmp;



	old_cr0_pg = kvm_read_cr0_bits(vcpu, X86_CR0_PG);



	hw_cr0 = (cr0 & ~KVM_VM_CR0_ALWAYS_OFF);

	if (is_unrestricted_guest(vcpu))

		hw_cr0 |= KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST;
@@ -3021,11 +3023,16 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
			enter_rmode(vcpu);

	}



	vmcs_writel(CR0_READ_SHADOW, cr0);

	vmcs_writel(GUEST_CR0, hw_cr0);

	vcpu->arch.cr0 = cr0;

	kvm_register_mark_available(vcpu, VCPU_EXREG_CR0);



#ifdef CONFIG_X86_64

	if (vcpu->arch.efer & EFER_LME) {

		if (!is_paging(vcpu) && (cr0 & X86_CR0_PG))

		if (!old_cr0_pg && (cr0 & X86_CR0_PG))

			enter_lmode(vcpu);

		if (is_paging(vcpu) && !(cr0 & X86_CR0_PG))

		else if (old_cr0_pg && !(cr0 & X86_CR0_PG))

			exit_lmode(vcpu);

	}

#endif
@@ -3066,16 +3073,10 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
			exec_controls_set(vmx, tmp);

		}



		if (!is_paging(vcpu) != !(cr0 & X86_CR0_PG)) {

			vcpu->arch.cr0 = cr0;

		/* Note, vmx_set_cr4() consumes the new vcpu->arch.cr0. */

		if ((old_cr0_pg ^ cr0) & X86_CR0_PG)

			vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));

	}

	}



	vmcs_writel(CR0_READ_SHADOW, cr0);

	vmcs_writel(GUEST_CR0, hw_cr0);

	vcpu->arch.cr0 = cr0;

	kvm_register_mark_available(vcpu, VCPU_EXREG_CR0);



	/* depends on vcpu->arch.cr0 to be set to a new value */

	vmx->emulation_required = emulation_required(vcpu);