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Commit b09408d0 authored by Marcelo Tosatti's avatar Marcelo Tosatti
Browse files

KVM: VMX: fix incorrect cached cpl value with real/v8086 modes 



CPL is always 0 when in real mode, and always 3 when virtual 8086 mode.

Using values other than those can cause failures on operations that
check CPL.

Reviewed-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent b0cfeb5d

arch/x86/kvm/vmx.c

+4 −11
Original line number Diff line number Diff line
@@ -1696,7 +1696,6 @@ static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu) 
static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)

{

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

	__clear_bit(VCPU_EXREG_CPL, (ulong *)&vcpu->arch.regs_avail);

	to_vmx(vcpu)->rflags = rflags;

	if (to_vmx(vcpu)->rmode.vm86_active) {

		to_vmx(vcpu)->rmode.save_rflags = rflags;
@@ -3110,7 +3109,6 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
	vmcs_writel(CR0_READ_SHADOW, cr0);

	vmcs_writel(GUEST_CR0, hw_cr0);

	vcpu->arch.cr0 = cr0;

	__clear_bit(VCPU_EXREG_CPL, (ulong *)&vcpu->arch.regs_avail);

}



static u64 construct_eptp(unsigned long root_hpa)
@@ -3220,8 +3218,10 @@ static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg) 
	return vmx_read_guest_seg_base(to_vmx(vcpu), seg);

}



static int __vmx_get_cpl(struct kvm_vcpu *vcpu)

static int vmx_get_cpl(struct kvm_vcpu *vcpu)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);



	if (!is_protmode(vcpu))

		return 0;
@@ -3229,13 +3229,6 @@ static int __vmx_get_cpl(struct kvm_vcpu *vcpu) 
	    && (kvm_get_rflags(vcpu) & X86_EFLAGS_VM)) /* if virtual 8086 */

		return 3;



	return vmx_read_guest_seg_selector(to_vmx(vcpu), VCPU_SREG_CS) & 3;

}



static int vmx_get_cpl(struct kvm_vcpu *vcpu)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);



	/*

	 * If we enter real mode with cs.sel & 3 != 0, the normal CPL calculations

	 * fail; use the cache instead.
@@ -3246,7 +3239,7 @@ static int vmx_get_cpl(struct kvm_vcpu *vcpu) 


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

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

		vmx->cpl = __vmx_get_cpl(vcpu);

		vmx->cpl = vmx_read_guest_seg_selector(vmx, VCPU_SREG_CS) & 3;

	}



	return vmx->cpl;