From ac9b305caa0df6f5b75d294e4b86c1027648991e Mon Sep 17 00:00:00 2001 From: Liran Alon Date: Mon, 6 Nov 2017 16:15:10 +0200 Subject: KVM: nVMX/nSVM: Don't intercept #UD when running L2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When running L2, #UD should be intercepted by L1 or just forwarded directly to L2. It should not reach L0 x86 emulator. Therefore, set intercept for #UD only based on L1 exception-bitmap. Also add WARN_ON_ONCE() on L0 #UD intercept handlers to make sure it is never reached while running L2. This improves commit ae1f57670703 ("KVM: nVMX: Do not emulate #UD while in guest mode") by removing an unnecessary exit from L2 to L0 on #UD when L1 doesn't intercept it. In addition, SVM L0 #UD intercept handler doesn't handle correctly the case it is raised from L2. In this case, it should forward the #UD to guest instead of x86 emulator. As done in VMX #UD intercept handler. This commit fixes this issue as-well. Signed-off-by: Liran Alon Reviewed-by: Nikita Leshenko Reviewed-by: Konrad Rzeszutek Wilk Signed-off-by: Konrad Rzeszutek Wilk Reviewed-by: Paolo Bonzini Reviewed-by: Wanpeng Li Signed-off-by: Radim Krčmář --- arch/x86/kvm/svm.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'arch/x86/kvm/svm.c') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 59e13a79c2e3..1bf7c09d97e6 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -361,6 +361,7 @@ static void recalc_intercepts(struct vcpu_svm *svm) { struct vmcb_control_area *c, *h; struct nested_state *g; + u32 h_intercept_exceptions; mark_dirty(svm->vmcb, VMCB_INTERCEPTS); @@ -371,9 +372,14 @@ static void recalc_intercepts(struct vcpu_svm *svm) h = &svm->nested.hsave->control; g = &svm->nested; + /* No need to intercept #UD if L1 doesn't intercept it */ + h_intercept_exceptions = + h->intercept_exceptions & ~(1U << UD_VECTOR); + c->intercept_cr = h->intercept_cr | g->intercept_cr; c->intercept_dr = h->intercept_dr | g->intercept_dr; - c->intercept_exceptions = h->intercept_exceptions | g->intercept_exceptions; + c->intercept_exceptions = + h_intercept_exceptions | g->intercept_exceptions; c->intercept = h->intercept | g->intercept; } @@ -2196,6 +2202,7 @@ static int ud_interception(struct vcpu_svm *svm) { int er; + WARN_ON_ONCE(is_guest_mode(&svm->vcpu)); er = emulate_instruction(&svm->vcpu, EMULTYPE_TRAP_UD); if (er != EMULATE_DONE) kvm_queue_exception(&svm->vcpu, UD_VECTOR); -- cgit v1.2.3 From 61cb57c9ed631c95b54f8e9090c89d18b3695b3c Mon Sep 17 00:00:00 2001 From: Liran Alon Date: Sun, 5 Nov 2017 16:56:32 +0200 Subject: KVM: x86: Exit to user-mode on #UD intercept when emulator requires MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instruction emulation after trapping a #UD exception can result in an MMIO access, for example when emulating a MOVBE on a processor that doesn't support the instruction. In this case, the #UD vmexit handler must exit to user mode, but there wasn't any code to do so. Add it for both VMX and SVM. Signed-off-by: Liran Alon Reviewed-by: Nikita Leshenko Reviewed-by: Konrad Rzeszutek Wilk Signed-off-by: Konrad Rzeszutek Wilk Reviewed-by: Wanpeng Li Reviewed-by: Paolo Bonzini Cc: stable@vger.kernel.org Signed-off-by: Radim Krčmář --- arch/x86/kvm/svm.c | 2 ++ arch/x86/kvm/vmx.c | 2 ++ 2 files changed, 4 insertions(+) (limited to 'arch/x86/kvm/svm.c') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 1bf7c09d97e6..eb714f1cdf7e 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2204,6 +2204,8 @@ static int ud_interception(struct vcpu_svm *svm) WARN_ON_ONCE(is_guest_mode(&svm->vcpu)); er = emulate_instruction(&svm->vcpu, EMULTYPE_TRAP_UD); + if (er == EMULATE_USER_EXIT) + return 0; if (er != EMULATE_DONE) kvm_queue_exception(&svm->vcpu, UD_VECTOR); return 1; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d319e2666ad5..65f1f06f6aaa 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5919,6 +5919,8 @@ static int handle_exception(struct kvm_vcpu *vcpu) if (is_invalid_opcode(intr_info)) { WARN_ON_ONCE(is_guest_mode(vcpu)); er = emulate_instruction(vcpu, EMULTYPE_TRAP_UD); + if (er == EMULATE_USER_EXIT) + return 0; if (er != EMULATE_DONE) kvm_queue_exception(vcpu, UD_VECTOR); return 1; -- cgit v1.2.3