This is a note to let you know that I've just added the patch titled
KVM: x86: Exit to user-mode on #UD intercept when emulator requires
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: kvm-x86-exit-to-user-mode-on-ud-intercept-when-emulator-requires.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 61cb57c9ed631c95b54f8e9090c89d18b3695b3c Mon Sep 17 00:00:00 2001
From: Liran Alon liran.alon@oracle.com 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
From: Liran Alon liran.alon@oracle.com
commit 61cb57c9ed631c95b54f8e9090c89d18b3695b3c upstream.
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 liran.alon@oracle.com Reviewed-by: Nikita Leshenko nikita.leshchenko@oracle.com Reviewed-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Signed-off-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Reviewed-by: Wanpeng Li wanpeng.li@hotmail.com Reviewed-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Radim Krčmář rkrcmar@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/svm.c | 2 ++ arch/x86/kvm/vmx.c | 2 ++ 2 files changed, 4 insertions(+)
--- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2149,6 +2149,8 @@ static int ud_interception(struct vcpu_s int er;
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; --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5502,6 +5502,8 @@ static int handle_exception(struct kvm_v return 1; } 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;
Patches currently in stable-queue which might be from liran.alon@oracle.com are
queue-4.9/kvm-x86-exit-to-user-mode-on-ud-intercept-when-emulator-requires.patch queue-4.9/kvm-x86-pvclock-handle-first-time-write-to-pvclock-page-contains-random-junk.patch