Patch "[Variant 2/Spectre-v2] arm64: Kill PSCI_GET_VERSION as a variant-2 workaround" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

[Variant 2/Spectre-v2] arm64: Kill PSCI_GET_VERSION as a variant-2 workaround

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-kill-psci_get_version-as-a-variant-2-workaround.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 <[email protected]> know about it.

From: Marc Zyngier <[email protected]>
Date: Tue, 6 Feb 2018 17:56:21 +0000
Subject: [Variant 2/Spectre-v2] arm64: Kill PSCI_GET_VERSION as a variant-2 workaround

From: Marc Zyngier <[email protected]>

Commit 3a0a397ff5ff upstream.

Now that we've standardised on SMCCC v1.1 to perform the branch prediction invalidation, let's drop the previous band-aid. If vendors haven't updated their firmware to do SMCCC 1.1, they haven't updated PSCI either, so we don't loose anything.

---
 arch/arm64/kernel/bpi.S        |   24 ---------------------
 arch/arm64/kernel/cpu_errata.c |   45 +++++++++++------------------------------
 arch/arm64/kvm/hyp/switch.c    |   14 ------------
 3 files changed, 13 insertions(+), 70 deletions(-)

@@ -54,30 +54,6 @@ ENTRY(__bp_harden_hyp_vecs_start)
 	vectors __kvm_hyp_vector
 	.endr
 ENTRY(__bp_harden_hyp_vecs_end)
-ENTRY(__psci_hyp_bp_inval_start)
-	sub	sp, sp, #(8 * 18)
-	stp	x16, x17, [sp, #(16 * 0)]
-	stp	x14, x15, [sp, #(16 * 1)]
-	stp	x12, x13, [sp, #(16 * 2)]
-	stp	x10, x11, [sp, #(16 * 3)]
-	stp	x8, x9, [sp, #(16 * 4)]
-	stp	x6, x7, [sp, #(16 * 5)]
-	stp	x4, x5, [sp, #(16 * 6)]
-	stp	x2, x3, [sp, #(16 * 7)]
-	stp	x0, x1, [sp, #(16 * 8)]
-	mov	x0, #0x84000000
-	smc	#0
-	ldp	x16, x17, [sp, #(16 * 0)]
-	ldp	x14, x15, [sp, #(16 * 1)]
-	ldp	x12, x13, [sp, #(16 * 2)]
-	ldp	x10, x11, [sp, #(16 * 3)]
-	ldp	x8, x9, [sp, #(16 * 4)]
-	ldp	x6, x7, [sp, #(16 * 5)]
-	ldp	x4, x5, [sp, #(16 * 6)]
-	ldp	x2, x3, [sp, #(16 * 7)]
-	ldp	x0, x1, [sp, #(16 * 8)]
-	add	sp, sp, #(8 * 18)
-ENTRY(__psci_hyp_bp_inval_end)
 
 ENTRY(__qcom_hyp_sanitize_link_stack_start)
 	stp     x29, x30, [sp, #-16]!

@@ -325,20 +325,6 @@ 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)) {
-		u32 val = vcpu_get_reg(vcpu, 0);
-
-		if (val == PSCI_0_2_FN_PSCI_VERSION) {
-			val = kvm_psci_version(vcpu, kern_hyp_va(vcpu->kvm));
-			if (unlikely(val == KVM_ARM_PSCI_0_1))
-				val = PSCI_RET_NOT_SUPPORTED;
-			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 [email protected] are

queue-4.14/arm-arm64-smccc-make-function-identifiers-an-unsigned-quantity.patch queue-4.14/arm64-move-bp-hardening-to-check_and_switch_context.patch queue-4.14/arm-arm64-kvm-advertise-smccc-v1.1.patch queue-4.14/arm64-move-post_ttbr_update_workaround-to-c-code.patch queue-4.14/firmware-psci-expose-psci-conduit.patch queue-4.14/arm64-force-kpti-to-be-disabled-on-cavium-thunderx.patch queue-4.14/arm64-entry-apply-bp-hardening-for-high-priority-synchronous-exceptions.patch queue-4.14/arm64-kpti-fix-the-interaction-between-asid-switching-and-software-pan.patch queue-4.14/firmware-psci-expose-smccc-version-through-psci_ops.patch queue-4.14/arm64-implement-branch-predictor-hardening-for-affected-cortex-a-cpus.patch queue-4.14/arm-arm64-kvm-add-psci_version-helper.patch queue-4.14/arm64-kill-psci_get_version-as-a-variant-2-workaround.patch queue-4.14/arm64-entry-apply-bp-hardening-for-suspicious-interrupts-from-el0.patch queue-4.14/arm64-capabilities-handle-duplicate-entries-for-a-capability.patch queue-4.14/arm64-add-arm_smccc_arch_workaround_1-bp-hardening-support.patch queue-4.14/arm-arm64-kvm-turn-kvm_psci_version-into-a-static-inline.patch queue-4.14/arm-arm64-kvm-implement-psci-1.0-support.patch queue-4.14/arm64-kvm-add-smccc_arch_workaround_1-fast-handling.patch queue-4.14/arm64-kvm-report-smccc_arch_workaround_1-bp-hardening-support.patch queue-4.14/arm-arm64-smccc-implement-smccc-v1.1-inline-primitive.patch queue-4.14/arm64-idmap-use-awx-flags-for-.idmap.text-.pushsection-directives.patch queue-4.14/arm64-kvm-make-psci_version-a-fast-path.patch queue-4.14/arm64-cpufeature-__this_cpu_has_cap-shouldn-t-stop-early.patch queue-4.14/arm64-kpti-add-enable-callback-to-remap-swapper-using-ng-mappings.patch queue-4.14/arm-arm64-kvm-consolidate-the-psci-include-files.patch queue-4.14/arm64-add-skeleton-to-harden-the-branch-predictor-against-aliasing-attacks.patch queue-4.14/arm-arm64-kvm-add-smccc-accessors-to-psci-code.patch queue-4.14/arm64-kvm-use-per-cpu-vector-when-bp-hardening-is-enabled.patch queue-4.14/arm64-kvm-increment-pc-after-handling-an-smc-trap.patch