This is a note to let you know that I've just added the patch titled

KVM: x86: emulator: Return to user-mode on L1 CPL=0 emulation failure

to the 4.14-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-emulator-return-to-user-mode-on-l1-cpl-0-emulation-failure.patch and it can be found in the queue-4.14 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 foo@baz Thu Feb 1 13:45:42 CET 2018

From: Liran Alon liran.alon@oracle.com Date: Sun, 5 Nov 2017 16:56:33 +0200 Subject: KVM: x86: emulator: Return to user-mode on L1 CPL=0 emulation failure

From: Liran Alon liran.alon@oracle.com

[ Upstream commit 1f4dcb3b213235e642088709a1c54964d23365e9 ]

On this case, handle_emulation_failure() fills kvm_run with internal-error information which it expects to be delivered to user-mode for further processing. However, the code reports a wrong return-value which makes KVM to never return to user-mode on this scenario.

Fixes: 6d77dbfc88e3 ("KVM: inject #UD if instruction emulation fails and exit to userspace")

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 Signed-off-by: Radim Krčmář rkrcmar@redhat.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5416,7 +5416,7 @@ static int handle_emulation_failure(stru vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; vcpu->run->internal.ndata = 0; - r = EMULATE_FAIL; + r = EMULATE_USER_EXIT; } kvm_queue_exception(vcpu, UD_VECTOR);

Patches currently in stable-queue which might be from liran.alon@oracle.com are

queue-4.14/kvm-nvmx-fix-vmx_check_nested_events-return-value-in-case-an-event-was-reinjected-to-l2.patch queue-4.14/kvm-x86-don-t-re-execute-instruction-when-not-passing-cr2-value.patch queue-4.14/kvm-x86-ioapic-preserve-read-only-values-in-the-redirection-table.patch queue-4.14/kvm-x86-ioapic-fix-level-triggered-eoi-and-ioapic-reconfigure-race.patch queue-4.14/kvm-x86-emulator-return-to-user-mode-on-l1-cpl-0-emulation-failure.patch queue-4.14/kvm-nvmx-nsvm-don-t-intercept-ud-when-running-l2.patch queue-4.14/kvm-x86-ioapic-clear-remote-irr-when-entry-is-switched-to-edge-triggered.patch