From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1735ECDFBB for ; Fri, 20 Jul 2018 12:32:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A20D820854 for ; Fri, 20 Jul 2018 12:32:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A20D820854 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388580AbeGTNUZ (ORCPT ); Fri, 20 Jul 2018 09:20:25 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40086 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732091AbeGTNUY (ORCPT ); Fri, 20 Jul 2018 09:20:24 -0400 Received: from localhost (LFbn-1-12238-233.w90-92.abo.wanadoo.fr [90.92.53.233]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 93001C22; Fri, 20 Jul 2018 12:31:17 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Mark Rutland , Marc Zyngier , Catalin Marinas Subject: [PATCH 4.9 64/66] arm64: KVM: Handle guests ARCH_WORKAROUND_2 requests Date: Fri, 20 Jul 2018 14:14:21 +0200 Message-Id: <20180720121412.399011226@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180720121407.228772286@linuxfoundation.org> References: <20180720121407.228772286@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marc Zyngier commit b4f18c063a13dfb33e3a63fe1844823e19c2265e upstream. In order to forward the guest's ARCH_WORKAROUND_2 calls to EL3, add a small(-ish) sequence to handle it at EL2. Special care must be taken to track the state of the guest itself by updating the workaround flags. We also rely on patching to enable calls into the firmware. Note that since we need to execute branches, this always executes after the Spectre-v2 mitigation has been applied. Reviewed-by: Mark Rutland Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/asm-offsets.c | 1 + arch/arm64/kvm/hyp/hyp-entry.S | 38 +++++++++++++++++++++++++++++++++++++- 2 files changed, 38 insertions(+), 1 deletion(-) --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -127,6 +127,7 @@ int main(void) BLANK(); #ifdef CONFIG_KVM_ARM_HOST DEFINE(VCPU_CONTEXT, offsetof(struct kvm_vcpu, arch.ctxt)); + DEFINE(VCPU_WORKAROUND_FLAGS, offsetof(struct kvm_vcpu, arch.workaround_flags)); DEFINE(CPU_GP_REGS, offsetof(struct kvm_cpu_context, gp_regs)); DEFINE(CPU_USER_PT_REGS, offsetof(struct kvm_regs, regs)); DEFINE(CPU_FP_REGS, offsetof(struct kvm_regs, fp_regs)); --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -107,8 +107,44 @@ el1_hvc_guest: */ ldr x1, [sp] // Guest's x0 eor w1, w1, #ARM_SMCCC_ARCH_WORKAROUND_1 + cbz w1, wa_epilogue + + /* ARM_SMCCC_ARCH_WORKAROUND_2 handling */ + eor w1, w1, #(ARM_SMCCC_ARCH_WORKAROUND_1 ^ \ + ARM_SMCCC_ARCH_WORKAROUND_2) cbnz w1, el1_trap - mov x0, x1 + +#ifdef CONFIG_ARM64_SSBD +alternative_cb arm64_enable_wa2_handling + b wa2_end +alternative_cb_end + get_vcpu_ptr x2, x0 + ldr x0, [x2, #VCPU_WORKAROUND_FLAGS] + + // Sanitize the argument and update the guest flags + ldr x1, [sp, #8] // Guest's x1 + clz w1, w1 // Murphy's device: + lsr w1, w1, #5 // w1 = !!w1 without using + eor w1, w1, #1 // the flags... + bfi x0, x1, #VCPU_WORKAROUND_2_FLAG_SHIFT, #1 + str x0, [x2, #VCPU_WORKAROUND_FLAGS] + + /* Check that we actually need to perform the call */ + hyp_ldr_this_cpu x0, arm64_ssbd_callback_required, x2 + cbz x0, wa2_end + + mov w0, #ARM_SMCCC_ARCH_WORKAROUND_2 + smc #0 + + /* Don't leak data from the SMC call */ + mov x3, xzr +wa2_end: + mov x2, xzr + mov x1, xzr +#endif + +wa_epilogue: + mov x0, xzr add sp, sp, #16 eret