* [PATCH] arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2
@ 2016-10-14 14:49 Vladimir Murzin
2016-10-26 8:42 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Vladimir Murzin @ 2016-10-14 14:49 UTC (permalink / raw)
To: stable; +Cc: vladimir.murzin, christoffer.dall, james.morse, marc.zyngier
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")
[ rebased for v4.7+ ]
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>
Cc: <stable@vger.kernel.org> # v4.6+
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
arch/arm64/kvm/hyp/entry.S | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index ce9e5e5..eaf08d3 100644
--- 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)]
--
1.7.9.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2
2016-10-14 14:49 [PATCH] arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2 Vladimir Murzin
@ 2016-10-26 8:42 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2016-10-26 8:42 UTC (permalink / raw)
To: Vladimir Murzin; +Cc: stable, christoffer.dall, james.morse, marc.zyngier
On Fri, Oct 14, 2016 at 03:49:12PM +0100, Vladimir Murzin wrote:
> 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")
>
> [ rebased for v4.7+ ]
Thanks for the rebase!
greg k-h
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2016-10-14 14:49 [PATCH] arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2 Vladimir Murzin
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