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%3Ba=su...

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@vger.kernel.org know about it.

From bfe766cf65fb65e68c4764f76158718560bdcee5 Mon Sep 17 00:00:00 2001

From: Julien Thierry julien.thierry@arm.com Date: Wed, 6 Dec 2017 17:09:49 +0000 Subject: arm64: kvm: Prevent restoring stale PMSCR_EL1 for vcpu

From: Julien Thierry julien.thierry@arm.com

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@arm.com Cc: Christoffer Dall christoffer.dall@linaro.org Cc: Marc Zyngier marc.zyngier@arm.com Cc: Catalin Marinas catalin.marinas@arm.com Reviewed-by: Will Deacon will.deacon@arm.com Reviewed-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- 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@arm.com are

queue-4.14/arm64-kvm-prevent-restoring-stale-pmscr_el1-for-vcpu.patch