This is a note to let you know that I've just added the patch titled
arm64: kvm: Prevent restoring stale PMSCR_EL1 for vcpu
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:
arm64-kvm-prevent-restoring-stale-pmscr_el1-for-vcpu.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 <stable@xxxxxxxxxxxxxxx> know about it.
>From bfe766cf65fb65e68c4764f76158718560bdcee5 Mon Sep 17 00:00:00 2001
From: Julien Thierry <julien.thierry@xxxxxxx>
Date: Wed, 6 Dec 2017 17:09:49 +0000
Subject: arm64: kvm: Prevent restoring stale PMSCR_EL1 for vcpu
From: Julien Thierry <julien.thierry@xxxxxxx>
commit bfe766cf65fb65e68c4764f76158718560bdcee5 upstream.
When VHE is not present, KVM needs to save and restores PMSCR_EL1 when
possible. If SPE is used by the host, value of PMSCR_EL1 cannot be saved
for the guest.
If the host starts using SPE between two save+restore on the same vcpu,
restore will write the value of PMSCR_EL1 read during the first save.
Make sure __debug_save_spe_nvhe clears the value of the saved PMSCR_EL1
when the guest cannot use SPE.
Signed-off-by: Julien Thierry <julien.thierry@xxxxxxx>
Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Reviewed-by: Will Deacon <will.deacon@xxxxxxx>
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kvm/hyp/debug-sr.c | 3 +++
1 file changed, 3 insertions(+)
--- a/arch/arm64/kvm/hyp/debug-sr.c
+++ b/arch/arm64/kvm/hyp/debug-sr.c
@@ -84,6 +84,9 @@ static void __hyp_text __debug_save_spe_
{
u64 reg;
+ /* Clear pmscr in case of early return */
+ *pmscr_el1 = 0;
+
/* SPE present on this CPU? */
if (!cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
ID_AA64DFR0_PMSVER_SHIFT))
Patches currently in stable-queue which might be from julien.thierry@xxxxxxx are
queue-4.14/arm64-kvm-prevent-restoring-stale-pmscr_el1-for-vcpu.patch