Patch "KVM: vmx: fix VPID is 0000H in non-root operation" has been added to the 4.2-stable tree

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

KVM: vmx: fix VPID is 0000H in non-root operation

to the 4.2-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-vmx-fix-vpid-is-0000h-in-non-root-operation.patch

and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Wanpeng Li <[email protected]>
Date: Wed, 16 Sep 2015 19:31:11 +0800
Subject: KVM: vmx: fix VPID is 0000H in non-root operation
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From: Wanpeng Li <[email protected]>

commit 04bb92e4b4cf06a66889d37b892b78f926faa9d4 upstream.

Reference SDM 28.1:

The current VPID is 0000H in the following situations:
- Outside VMX operation. (This includes operation in system-management mode under the default treatment of SMIs and SMM with VMX operation; see Section 34.14.)
- In VMX root operation.
- In VMX non-root operation when the “enable VPID” VM-execution control is 0.

The VPID should never be 0000H in non-root operation when "enable VPID" VM-execution control is 1. However, commit 34a1cd60 ("kvm: x86: vmx:
move some vmx setting from vmx_init() to hardware_setup()") remove the codes which reserve 0000H for VMX root operation.

This patch fix it by again reserving 0000H for VMX root operation.

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

@@ -6134,6 +6134,8 @@ static __init int hardware_setup(void)
 	memcpy(vmx_msr_bitmap_longmode_x2apic,
 			vmx_msr_bitmap_longmode, PAGE_SIZE);
 
+	set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
+
 	if (enable_apicv) {
 		for (msr = 0x800; msr <= 0x8ff; msr++)
 			vmx_disable_intercept_msr_read_x2apic(msr);

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

queue-4.2/kvm-vmx-fix-vpid-is-0000h-in-non-root-operation.patch