!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
vmx->nested.vmcs01_guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);
+ /*
+ * Overwrite vmcs01.GUEST_CR3 with L1's CR3 if EPT is disabled *and*
+ * nested early checks are disabled. In the event of a "late" VM-Fail,
+ * i.e. a VM-Fail detected by hardware but not KVM, KVM must unwind its
+ * software model to the pre-VMEntry host state. When EPT is disabled,
+ * GUEST_CR3 holds KVM's shadow CR3, not L1's "real" CR3, which causes
+ * nested_vmx_restore_host_state() to corrupt vcpu->arch.cr3. Stuffing
+ * vmcs01.GUEST_CR3 results in the unwind naturally setting arch.cr3 to
+ * the correct value. Smashing vmcs01.GUEST_CR3 is safe because nested
+ * VM-Exits, and the unwind, reset KVM's MMU, i.e. vmcs01.GUEST_CR3 is
+ * guaranteed to be overwritten with a shadow CR3 prior to re-entering
+ * L1. Don't stuff vmcs01.GUEST_CR3 when using nested early checks as
+ * KVM modifies vcpu->arch.cr3 if and only if the early hardware checks
+ * pass, and early VM-Fails do not reset KVM's MMU, i.e. the VM-Fail
+ * path would need to manually save/restore vmcs01.GUEST_CR3.
+ */
+ if (!enable_ept && !nested_early_check)
+ vmcs_writel(GUEST_CR3, vcpu->arch.cr3);
+
vmx_switch_vmcs(vcpu, &vmx->nested.vmcs02);
prepare_vmcs02_early(vmx, vmcs12);
vmx_set_cr4(vcpu, vmcs_readl(CR4_READ_SHADOW));
nested_ept_uninit_mmu_context(vcpu);
-
- /*
- * This is only valid if EPT is in use, otherwise the vmcs01 GUEST_CR3
- * points to shadow pages! Fortunately we only get here after a WARN_ON
- * if EPT is disabled, so a VMabort is perfectly fine.
- */
- if (enable_ept) {
- vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
- __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
- } else {
- nested_vmx_abort(vcpu, VMX_ABORT_VMCS_CORRUPTED);
- }
+ vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
+ __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
/*
* Use ept_save_pdptrs(vcpu) to load the MMU's cached PDPTRs
* VMFail, like everything else we just need to ensure our
* software model is up-to-date.
*/
- ept_save_pdptrs(vcpu);
+ if (enable_ept)
+ ept_save_pdptrs(vcpu);
kvm_mmu_reset_context(vcpu);
{
int i;
- /*
- * Without EPT it is not possible to restore L1's CR3 and PDPTR on
- * VMfail, because they are not available in vmcs01. Just always
- * use hardware checks.
- */
- if (!enable_ept)
- nested_early_check = 1;
-
if (!cpu_has_vmx_shadow_vmcs())
enable_shadow_vmcs = 0;
if (enable_shadow_vmcs) {