Patch "KVM/nVMX: Set the CPU_BASED_USE_MSR_BITMAPS if we have a valid L02 MSR bitmap" has been added to the 4.14-stable tree

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

KVM/nVMX: Set the CPU_BASED_USE_MSR_BITMAPS if we have a valid L02 MSR bitmap

to the 4.14-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-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch
and it can be found in the queue-4.14 subdirectory.

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

From: KarimAllah Ahmed <[email protected]>
Date: Sat, 10 Feb 2018 23:39:26 +0000
Subject: KVM/nVMX: Set the CPU_BASED_USE_MSR_BITMAPS if we have a valid L02 MSR bitmap
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From: KarimAllah Ahmed <[email protected]>

commit 3712caeb14dcb33fb4d5114f14c0beef10aca101 upstream.

We either clear the CPU_BASED_USE_MSR_BITMAPS and end up intercepting all MSR accesses or create a valid L02 MSR bitmap and use that. This decision has to be made every time we evaluate whether we are going to generate the L02 MSR bitmap.

Before commit:

d28b387fb74d ("KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRL")

... this was probably OK since the decision was always identical.

This is no longer the case now since the MSR bitmap might actually change once we decide to not intercept SPEC_CTRL and PRED_CMD.

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

@@ -10127,7 +10127,8 @@ static void nested_get_vmcs12_pages(stru
 	if (cpu_has_vmx_msr_bitmap() &&
 	    nested_cpu_has(vmcs12, CPU_BASED_USE_MSR_BITMAPS) &&
 	    nested_vmx_merge_msr_bitmap(vcpu, vmcs12))
-		;
+		vmcs_set_bits(CPU_BASED_VM_EXEC_CONTROL,
+			      CPU_BASED_USE_MSR_BITMAPS);
 	else
 		vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL,
 				CPU_BASED_USE_MSR_BITMAPS);

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

queue-4.14/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.14/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.14/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.14/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.14/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch