Patch "arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2" has been added to the 4.8-stable tree

Patch "arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2" has been added to the 4.8-stable tree

[gregkh]

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

    arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2

to the 4.8-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:
     arm64-kvm-vhe-reset-pstate.pan-on-entry-to-el2.patch
and it can be found in the queue-4.8 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 cb96408da4e11698674abd04aeac941c1bed2038 Mon Sep 17 00:00:00 2001
From: Vladimir Murzin <vladimir.murzin@arm.com>
Date: Thu, 1 Sep 2016 15:29:03 +0100
Subject: arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2

From: Vladimir Murzin <vladimir.murzin@arm.com>

commit cb96408da4e11698674abd04aeac941c1bed2038 upstream.

SCTLR_EL2.SPAN bit controls what happens with the PSTATE.PAN bit on an
exception. However, this bit has no effect on the PSTATE.PAN when
HCR_EL2.E2H or HCR_EL2.TGE is unset. Thus when VHE is used and
exception taken from a guest PSTATE.PAN bit left unchanged and we
continue with a value guest has set.

To address that always reset PSTATE.PAN on entry from EL1.

Fixes: 1f364c8c48a0 ("arm64: VHE: Add support for running Linux in EL2 mode")

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
[ rebased for v4.7+ ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 arch/arm64/kvm/hyp/entry.S |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -98,6 +98,8 @@ ENTRY(__guest_exit)
 	// x4-x29,lr: vcpu regs
 	// vcpu x0-x3 on the stack
 
+	ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
+
 	add	x2, x0, #VCPU_CONTEXT
 
 	stp	x4, x5,   [x2, #CPU_XREG_OFFSET(4)]


Patches currently in stable-queue which might be from vladimir.murzin@arm.com are

queue-4.8/arm64-kvm-vhe-reset-pstate.pan-on-entry-to-el2.patch