This is a note to let you know that I've just added the patch titled
[Variant 2/Spectre-v2] arm64: KVM: Make PSCI_VERSION a fast path
to the 4.15-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-make-psci_version-a-fast-path.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Feb 13 17:25:10 CET 2018
From: Marc Zyngier <marc.zyngier@xxxxxxx>
Date: Wed, 3 Jan 2018 16:38:37 +0000
Subject: [Variant 2/Spectre-v2] arm64: KVM: Make PSCI_VERSION a fast path
From: Marc Zyngier <marc.zyngier@xxxxxxx>
Commit 90348689d500 upstream.
For those CPUs that require PSCI to perform a BP invalidation,
going all the way to the PSCI code for not much is a waste of
precious cycles. Let's terminate that call as early as possible.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kvm/hyp/switch.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -17,6 +17,7 @@
#include <linux/types.h>
#include <linux/jump_label.h>
+#include <uapi/linux/psci.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
@@ -341,6 +342,18 @@ again:
if (exit_code == ARM_EXCEPTION_TRAP && !__populate_fault_info(vcpu))
goto again;
+ if (exit_code == ARM_EXCEPTION_TRAP &&
+ (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC64 ||
+ kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32) &&
+ vcpu_get_reg(vcpu, 0) == PSCI_0_2_FN_PSCI_VERSION) {
+ u64 val = PSCI_RET_NOT_SUPPORTED;
+ if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
+ val = 2;
+
+ vcpu_set_reg(vcpu, 0, val);
+ goto again;
+ }
+
if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&
exit_code == ARM_EXCEPTION_TRAP) {
bool valid;
Patches currently in stable-queue which might be from marc.zyngier@xxxxxxx are
queue-4.15/arm-arm64-smccc-make-function-identifiers-an-unsigned-quantity.patch
queue-4.15/arm64-move-bp-hardening-to-check_and_switch_context.patch
queue-4.15/arm-arm64-kvm-advertise-smccc-v1.1.patch
queue-4.15/arm64-move-post_ttbr_update_workaround-to-c-code.patch
queue-4.15/firmware-psci-expose-psci-conduit.patch
queue-4.15/arm64-force-kpti-to-be-disabled-on-cavium-thunderx.patch
queue-4.15/arm64-entry-apply-bp-hardening-for-high-priority-synchronous-exceptions.patch
queue-4.15/arm64-kpti-fix-the-interaction-between-asid-switching-and-software-pan.patch
queue-4.15/firmware-psci-expose-smccc-version-through-psci_ops.patch
queue-4.15/arm64-implement-branch-predictor-hardening-for-affected-cortex-a-cpus.patch
queue-4.15/arm-arm64-kvm-add-psci_version-helper.patch
queue-4.15/arm64-kill-psci_get_version-as-a-variant-2-workaround.patch
queue-4.15/arm64-entry-apply-bp-hardening-for-suspicious-interrupts-from-el0.patch
queue-4.15/arm64-capabilities-handle-duplicate-entries-for-a-capability.patch
queue-4.15/arm64-add-arm_smccc_arch_workaround_1-bp-hardening-support.patch
queue-4.15/arm-arm64-kvm-turn-kvm_psci_version-into-a-static-inline.patch
queue-4.15/arm-arm64-kvm-implement-psci-1.0-support.patch
queue-4.15/arm64-kvm-add-smccc_arch_workaround_1-fast-handling.patch
queue-4.15/arm64-kvm-report-smccc_arch_workaround_1-bp-hardening-support.patch
queue-4.15/arm-arm64-smccc-implement-smccc-v1.1-inline-primitive.patch
queue-4.15/arm64-idmap-use-awx-flags-for-.idmap.text-.pushsection-directives.patch
queue-4.15/arm64-kvm-make-psci_version-a-fast-path.patch
queue-4.15/arm64-cpufeature-__this_cpu_has_cap-shouldn-t-stop-early.patch
queue-4.15/arm64-kpti-add-enable-callback-to-remap-swapper-using-ng-mappings.patch
queue-4.15/arm-arm64-kvm-consolidate-the-psci-include-files.patch
queue-4.15/arm64-add-skeleton-to-harden-the-branch-predictor-against-aliasing-attacks.patch
queue-4.15/arm-arm64-kvm-add-smccc-accessors-to-psci-code.patch
queue-4.15/arm64-kvm-use-per-cpu-vector-when-bp-hardening-is-enabled.patch
queue-4.15/arm64-kvm-increment-pc-after-handling-an-smc-trap.patch