Patch "kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL" has been added to the 4.4-stable tree

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

kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL

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-fix-vmwrite-to-secondary_vm_exec_control.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 <[email protected]> know about it.

From: Huaitong Han <[email protected]>
Date: Tue, 12 Jan 2016 16:04:20 +0800
Subject: kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL

From: Huaitong Han <[email protected]>

commit 45bdbcfdf241149642fb6c25ab0c209d59c371b7 upstream.

vmx_cpuid_tries to update SECONDARY_VM_EXEC_CONTROL in the VMCS, but it will cause a vmwrite error on older CPUs because the code does not check for the presence of CPU_BASED_ACTIVATE_SECONDARY_CONTROLS.

This will get rid of the following trace on e.g. Core2 6600:

vmwrite error: reg 401e value 10 (err 12)

Call Trace:
[<ffffffff8116e2b9>] dump_stack+0x40/0x57
[<ffffffffa020b88d>] vmx_cpuid_update+0x5d/0x150 [kvm_intel]
[<ffffffffa01d8fdc>] kvm_vcpu_ioctl_set_cpuid2+0x4c/0x70 [kvm]
[<ffffffffa01b8363>] kvm_arch_vcpu_ioctl+0x903/0xfa0 [kvm]

---
 arch/x86/kvm/vmx.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -8932,7 +8932,8 @@ static void vmx_cpuid_update(struct kvm_
 			best->ebx &= ~bit(X86_FEATURE_INVPCID);
 	}
 
-	vmcs_set_secondary_exec_control(secondary_exec_ctl);
+	if (cpu_has_secondary_exec_ctrls())
+		vmcs_set_secondary_exec_control(secondary_exec_ctl);
 
 	if (static_cpu_has(X86_FEATURE_PCOMMIT) && nested) {
 		if (guest_cpuid_has_pcommit(vcpu))

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/kvm-x86-fix-vmwrite-to-secondary_vm_exec_control.patch