Patch "X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs" has been added to the 4.15-stable tree

Patch "X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs" has been added to the 4.15-stable tree

[gregkh]

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

    X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs

to the 4.15-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:
     x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 206587a9fb764d71f035dc7f6d3b6488f5d5b304 Mon Sep 17 00:00:00 2001
From: KarimAllah Ahmed <karahmed@amazon.de>
Date: Sat, 10 Feb 2018 23:39:25 +0000
Subject: X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: KarimAllah Ahmed <karahmed@amazon.de>

commit 206587a9fb764d71f035dc7f6d3b6488f5d5b304 upstream.

These two variables should check whether SPEC_CTRL and PRED_CMD are
supposed to be passed through to L2 guests or not. While
msr_write_intercepted_l01 would return 'true' if it is not passed through.

So just invert the result of msr_write_intercepted_l01 to implement the
correct semantics.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Jim Mattson <jmattson@google.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arjan.van.de.ven@intel.com
Cc: dave.hansen@intel.com
Cc: kvm@vger.kernel.org
Cc: sironi@amazon.de
Fixes: 086e7d4118cc ("KVM: VMX: Allow direct access to MSR_IA32_SPEC_CTRL")
Link: http://lkml.kernel.org/r/1518305967-31356-5-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kvm/vmx.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10220,8 +10220,8 @@ static inline bool nested_vmx_merge_msr_
 	 *    updated to reflect this when L1 (or its L2s) actually write to
 	 *    the MSR.
 	 */
-	bool pred_cmd = msr_write_intercepted_l01(vcpu, MSR_IA32_PRED_CMD);
-	bool spec_ctrl = msr_write_intercepted_l01(vcpu, MSR_IA32_SPEC_CTRL);
+	bool pred_cmd = !msr_write_intercepted_l01(vcpu, MSR_IA32_PRED_CMD);
+	bool spec_ctrl = !msr_write_intercepted_l01(vcpu, MSR_IA32_SPEC_CTRL);
 
 	if (!nested_cpu_has_virt_x2apic_mode(vmcs12) &&
 	    !pred_cmd && !spec_ctrl)


Patches currently in stable-queue which might be from karahmed@amazon.de are

queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch
queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch
queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch
queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch
queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch