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@xxxxxxxxxxxxxxx> know about it.
>From cb96408da4e11698674abd04aeac941c1bed2038 Mon Sep 17 00:00:00 2001
From: Vladimir Murzin <vladimir.murzin@xxxxxxx>
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@xxxxxxx>
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@xxxxxxx>
Reviewed-by: James Morse <james.morse@xxxxxxx>
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
[ rebased for v4.7+ ]
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxx are
queue-4.8/arm64-kvm-vhe-reset-pstate.pan-on-entry-to-el2.patch
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