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

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 <[email protected]> know about it.

From: Liran Alon <[email protected]>
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 <[email protected]>

[ 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.

---
 arch/x86/include/asm/kvm_host.h |    3 ++-
 arch/x86/kvm/vmx.c              |    2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

@@ -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);

@@ -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 [email protected] 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