Patch "KVM: x86: Don't re-execute instruction when not passing CR2 value" has been added to the 4.9-stable tree

Patch "KVM: x86: Don't re-execute instruction when not passing CR2 value" has been added to the 4.9-stable tree

[gregkh]

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

    KVM: x86: Don't re-execute instruction when not passing CR2 value

to the 4.9-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-don-t-re-execute-instruction-when-not-passing-cr2-value.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 foo@baz Thu Feb  1 13:58:04 CET 2018
From: Liran Alon <liran.alon@oracle.com>
Date: Sun, 5 Nov 2017 16:56:34 +0200
Subject: KVM: x86: Don't re-execute instruction when not passing CR2 value

From: Liran Alon <liran.alon@oracle.com>


[ Upstream commit 9b8ae63798cb97e785a667ff27e43fa6220cb734 ]

In case of instruction-decode failure or emulation failure,
x86_emulate_instruction() will call reexecute_instruction() which will
attempt to use the cr2 value passed to x86_emulate_instruction().
However, when x86_emulate_instruction() is called from
emulate_instruction(), cr2 is not passed (passed as 0) and therefore
it doesn't make sense to execute reexecute_instruction() logic at all.

Fixes: 51d8b66199e9 ("KVM: cleanup emulate_instruction")

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@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/include/asm/kvm_host.h |    3 ++-
 arch/x86/kvm/vmx.c              |    2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1113,7 +1113,8 @@ int x86_emulate_instruction(struct kvm_v
 static inline int emulate_instruction(struct kvm_vcpu *vcpu,
 			int emulation_type)
 {
-	return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0);
+	return x86_emulate_instruction(vcpu, 0,
+			emulation_type | EMULTYPE_NO_REEXECUTE, NULL, 0);
 }
 
 void kvm_enable_efer_bits(u64);
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6257,7 +6257,7 @@ static int handle_invalid_guest_state(st
 		if (test_bit(KVM_REQ_EVENT, &vcpu->requests))
 			return 1;
 
-		err = emulate_instruction(vcpu, EMULTYPE_NO_REEXECUTE);
+		err = emulate_instruction(vcpu, 0);
 
 		if (err == EMULATE_USER_EXIT) {
 			++vcpu->stat.mmio_exits;


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

queue-4.9/kvm-x86-don-t-re-execute-instruction-when-not-passing-cr2-value.patch
queue-4.9/kvm-x86-ioapic-preserve-read-only-values-in-the-redirection-table.patch
queue-4.9/kvm-x86-ioapic-fix-level-triggered-eoi-and-ioapic-reconfigure-race.patch
queue-4.9/kvm-x86-emulator-return-to-user-mode-on-l1-cpl-0-emulation-failure.patch
queue-4.9/kvm-x86-ioapic-clear-remote-irr-when-entry-is-switched-to-edge-triggered.patch