Patch "kvm: nVMX: Don't allow L2 to access the hardware CR8" has been added to the 4.13-stable tree

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

kvm: nVMX: Don't allow L2 to access the hardware CR8

to the 4.13-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-nvmx-don-t-allow-l2-to-access-the-hardware-cr8.patch
and it can be found in the queue-4.13 subdirectory.

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

From: Jim Mattson <[email protected]>
Date: Tue, 12 Sep 2017 13:02:54 -0700
Subject: kvm: nVMX: Don't allow L2 to access the hardware CR8

From: Jim Mattson <[email protected]>

commit 51aa68e7d57e3217192d88ce90fd5b8ef29ec94f upstream.

If L1 does not specify the "use TPR shadow" VM-execution control in vmcs12, then L0 must specify the "CR8-load exiting" and "CR8-store exiting" VM-execution controls in vmcs02. Failure to do so will give the L2 VM unrestricted read/write access to the hardware CR8.

This fixes CVE-2017-12154.

---
 arch/x86/kvm/vmx.c |    5 +++++
 1 file changed, 5 insertions(+)

@@ -10271,6 +10271,11 @@ static int prepare_vmcs02(struct kvm_vcp
 	if (exec_control & CPU_BASED_TPR_SHADOW) {
 		vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, -1ull);
 		vmcs_write32(TPR_THRESHOLD, vmcs12->tpr_threshold);
+	} else {
+#ifdef CONFIG_X86_64
+		exec_control |= CPU_BASED_CR8_LOAD_EXITING |
+				CPU_BASED_CR8_STORE_EXITING;
+#endif
 	}
 
 	/*

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

queue-4.13/kvm-nvmx-don-t-allow-l2-to-access-the-hardware-cr8.patch