KVM: x86: Defer the MMU unload to the normal path on an global INVPCID

commit f66c53b3b94f658590e1012bf6d922f8b7e01bda upstream.

Defer unloading the MMU after a INVPCID until the instruction emulation
has completed, i.e. until after RIP has been updated.

On VMX, this is a benign bug as VMX doesn't touch the MMU when skipping
an emulated instruction.  However, on SVM, if nrip is disabled, the
emulator is used to skip an instruction, which would lead to fireworks
if the emulator were invoked without a valid MMU.

Fixes: eb4b248e152d ("kvm: vmx: Support INVPCID in shadow paging mode")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210305011101.3597423-15-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f37f5c1430cfdf06479139e1051d5ff630f57f12..e9673bc4c3e3a7a64a3ec61becaa0224668582ae 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11407,7 +11407,7 @@ int kvm_handle_invpcid(struct kvm_vcpu *vcpu, unsigned long type, gva_t gva)
 
                fallthrough;
        case INVPCID_TYPE_ALL_INCL_GLOBAL:
-               kvm_mmu_unload(vcpu);
+               kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
                return kvm_skip_emulated_instruction(vcpu);
 
        default: