When writing 1 to CR0.PE, the CPL remains 0 even if bits 0-1 of CS
disagree. Before calling vmx_set_cr0, VCPU_EXREG_CPL was cleared
by vmx_vcpu_run, so set it again and make sure that enter_pmode
does not change it.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
arch/x86/kvm/vmx.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7dc5fdd30d7f..7440cce3bf30 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3102,7 +3102,7 @@ static void fix_pmode_seg(struct kvm_vcpu *vcpu, int seg,
* CS and SS RPL should be equal during guest entry according
* to VMX spec, but in reality it is not always so. Since vcpu
* is in the middle of the transition from real mode to
- * protected mode it is safe to assume that RPL 0 is a good
+ * protected mode, the CPL is 0; thus RPL 0 is a good
* default value.
*/
if (seg == VCPU_SREG_CS || seg == VCPU_SREG_SS)
@@ -3110,7 +3110,7 @@ static void fix_pmode_seg(struct kvm_vcpu *vcpu, int seg,
save->dpl = save->selector & SELECTOR_RPL_MASK;
save->s = 1;
}
- vmx_set_segment(vcpu, save, seg, false);
+ vmx_set_segment(vcpu, save, seg, true);
}
static void enter_pmode(struct kvm_vcpu *vcpu)
@@ -3151,10 +3151,6 @@ static void enter_pmode(struct kvm_vcpu *vcpu)
fix_pmode_seg(vcpu, VCPU_SREG_DS, &vmx->rmode.segs[VCPU_SREG_DS]);
fix_pmode_seg(vcpu, VCPU_SREG_FS, &vmx->rmode.segs[VCPU_SREG_FS]);
fix_pmode_seg(vcpu, VCPU_SREG_GS, &vmx->rmode.segs[VCPU_SREG_GS]);
-
- /* CPL is always 0 when CPU enters protected mode */
- __set_bit(VCPU_EXREG_CPL, (ulong *)&vcpu->arch.regs_avail);
- vmx->cpl = 0;
}
static void fix_rmode_seg(int seg, struct kvm_segment *save)
@@ -3397,11 +3393,21 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned
long cr0)
else {
hw_cr0 |= KVM_VM_CR0_ALWAYS_ON;
- if (vmx->rmode.vm86_active && (cr0 & X86_CR0_PE))
- enter_pmode(vcpu);
+ if (cr0 & X86_CR0_PE) {
+ /*
+ * CPL is always 0 when CPU enters protected
+ * mode, bits 0-1 of CS do not matter.
+ */
+ __set_bit(VCPU_EXREG_CPL,
+ (ulong *)&vcpu->arch.regs_avail);
+ vmx->cpl = 0;
- if (!vmx->rmode.vm86_active && !(cr0 & X86_CR0_PE))
- enter_rmode(vcpu);
+ if (vmx->rmode.vm86_active)
+ enter_pmode(vcpu);
+ } else {
+ if (!vmx->rmode.vm86_active)
+ enter_rmode(vcpu);
+ }
}
#ifdef CONFIG_X86_64
--
1.8.3.1
--
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