Commits
Sean Christopherson committed 815403a6ea8
KVM: nVMX: Always write vmcs02.GUEST_CR3 during nested VM-Enter commit 04f11ef45810da5ae2542dd78cc353f3761bd2cb upstream. Write the desired L2 CR3 into vmcs02.GUEST_CR3 during nested VM-Enter instead of deferring the VMWRITE until vmx_set_cr3(). If the VMWRITE is deferred, then KVM can consume a stale vmcs02.GUEST_CR3 when it refreshes vmcs12->guest_cr3 during nested_vmx_vmexit() if the emulated VM-Exit occurs without actually entering L2, e.g. if the nested run is squashed because nested VM-Enter (from L1) is putting L2 into HLT. Note, the above scenario can occur regardless of whether L1 is intercepting HLT, e.g. L1 can intercept HLT and then re-enter L2 with vmcs.GUEST_ACTIVITY_STATE=HALTED. But practically speaking, a VMM will likely put a guest into HALTED if and only if it's not intercepting HLT. In an ideal world where EPT *requires* unrestricted guest (and vice versa), VMX could handle CR3 similar to how it handles RSP and RIP, e.g. mark CR3 dirty and conditionally load it at vmx_vcpu_run(). But the unrestricted guest silliness complicates the dirty tracking logic to the point that explicitly handling vmcs02.GUEST_CR3 during nested VM-Enter is a simpler overall implementation. Cc: stable@vger.kernel.org Reported-and-tested-by: Reto Buerki <reet@codelabs.ch> Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Liran Alon <liran.alon@oracle.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>