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 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
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-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 61cb57c9ed631c95b54f8e9090c89d18b3695b3c Mon Sep 17 00:00:00 2001
From: Liran Alon <liran.alon@xxxxxxxxxx>
Date: Sun, 5 Nov 2017 16:56:32 +0200
Subject: KVM: x86: Exit to user-mode on #UD intercept when emulator requires
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From: Liran Alon <liran.alon@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@xxxxxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Reviewed-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -1696,6 +1696,8 @@ 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
@@ -5267,6 +5267,8 @@ 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@xxxxxxxxxx are
queue-4.4/kvm-x86-exit-to-user-mode-on-ud-intercept-when-emulator-requires.patch
queue-4.4/kvm-x86-pvclock-handle-first-time-write-to-pvclock-page-contains-random-junk.patch