From patchwork Fri Oct 18 16:10:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 176894 Delivered-To: patch@linaro.org Received: by 2002:a92:7e96:0:0:0:0:0 with SMTP id q22csp1065598ill; Fri, 18 Oct 2019 09:10:59 -0700 (PDT) X-Google-Smtp-Source: APXvYqwE8a1/XVMP+5XLlv8JdzKblqRneSaZ298+UK6dSxR1jtPvi/U25aVdne2P5IttFHQSn3MG X-Received: by 2002:a50:fc82:: with SMTP id f2mr10408123edq.262.1571415059750; Fri, 18 Oct 2019 09:10:59 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1571415059; cv=none; d=google.com; s=arc-20160816; b=qFTrp0fU0rKpcdvnzX2z2bgp5kD6Gi52AvNmMx8qxauBNReqO5EztQurOsClS5OBUk /DgQhZlJFPlGiGmKK1wuyjaMdLo6kMizyWZ0Oxygdj1YUbCvj4k5bN6Ql28Y2EXXe+yW M9MTIVBB4yH1T0fhD7kNnnX/dsAKuMxynAwMbYlSHlWbDA/6cFLYaLzZ5OFPcgy81FLT wuWWu6U4dtNyhhV5zcgHYRaVzmb1Lovd4yKMeT4VBLxaiLQLn7ynqh2vZuCuhrUNcJtr u8dLR0RFjLtK1Jzswx4Bdoehz0Z4N7AHBzpOAMWAWGAiKZOxk3L28SaDoGA8/wbm8Z2E 7avg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:from:subject:references :mime-version:message-id:in-reply-to:date:dkim-signature; bh=72rGRuWFiviz942NA6zVkn9gcWlAdBMK2y71uV80e5M=; b=MAQ5D1dgoAfQBJhVJ552oAjkJdL0cdi8NkqGOLGwmilyQD85mS6otwQXiiqauSMF4Y lQs8O+o0ah1nCx00BfddcCkybQxfsZmPnHzAy2bt5fTya6vle6snmhJ2pIsE0nRbbLXx ZpFsnNO1Wt2d8ufco/d9Zhm8qQxzqDM4FIbTinh7d2mP8J/BgssE6OT6kpTVe03dYv+L 4hDThXhuom0wHDa7ni5xlW5hgX7qZrsjM39jPg+NPr23THeTzFVKbF4vyLmgYqzuCYJk lYgdpcnWxXAc6vfwXiQW5hJzIbs/s4Rq4BhPZTR7pp/1OMsDxcg9L5ADHPpERsqJs5k9 rpig== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=ZvzQdFSz; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p10si3583415ejz.391.2019.10.18.09.10.59; Fri, 18 Oct 2019 09:10:59 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=ZvzQdFSz; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2442935AbfJRQK6 (ORCPT + 26 others); Fri, 18 Oct 2019 12:10:58 -0400 Received: from mail-yw1-f73.google.com ([209.85.161.73]:42610 "EHLO mail-yw1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2442650AbfJRQK4 (ORCPT ); Fri, 18 Oct 2019 12:10:56 -0400 Received: by mail-yw1-f73.google.com with SMTP id o14so4756872ywa.9 for ; Fri, 18 Oct 2019 09:10:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=72rGRuWFiviz942NA6zVkn9gcWlAdBMK2y71uV80e5M=; b=ZvzQdFSzTLbEjP4zxdusVf3ReL3ljnpZzJfPdrbpnE9rMeefuhQHID/ee1FAoqvYLH O+/PdDLy+eoWqhA9UIEIUFRCMC5xqhNowPZWx2ww/HoS+63BhQ5I1HOf+y5t9GV4AlzB 4wvvMPqaOkuUSsDFHTVS6xJHhNUp3s1c9Y1ghonvzQD2ZPiXv5LmNp53Biqgoh9GKiCJ afEukw6/WMLv2boh6kNWUds4TgOnVVcCplvVwI02NOYpPnoOVZxpUv2JWmCC5FcJjdP9 qyuCgJgGG2jATFBKXIAZK/fXaf2KYXXK+X2rgvP6lspQZZSv0gH/6LOEhAEKe42LtQC+ cKeg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=72rGRuWFiviz942NA6zVkn9gcWlAdBMK2y71uV80e5M=; b=KM9cLDQVbkXw8R8pQK3de3EhZz+xtiCoX4JVxt8+DtmDiPqQqYjHn+dCOgOEV90ld4 +3q34txxsMtLjaweWEF4UkcmsRWxBpjGh5C1YFBt3qXyQRJd4As70+Ltbv3GQeMm1hAY d5BIZd/6YVCoKg0tLiQSvKoCKWyadw9fpjjVbRNvKWiG30AlNaZYHSz2tscqWviyxZCE VXInN0C1viGICmXxbj0xzrvIae7CsofC4AVJcX6QhqCpPuhDrPLV4j9FKWSvRMUIpKSZ B54KBby6v3SMApRmZVf8njFRSkfblBXIme0Wtx5xEjlc2hUYvcUwdGT5xIJu1XzB9j0I SS9A== X-Gm-Message-State: APjAAAXQQh1diR16xUFviAghnSLROnVPL5CCiyeCXdAM3tllnSP2ZFBx fxsCLfjf/MOfxRp56aMmwOdCE4GAgXEt1RED3d8= X-Received: by 2002:a0d:d804:: with SMTP id a4mr7899178ywe.454.1571415054615; Fri, 18 Oct 2019 09:10:54 -0700 (PDT) Date: Fri, 18 Oct 2019 09:10:18 -0700 In-Reply-To: <20191018161033.261971-1-samitolvanen@google.com> Message-Id: <20191018161033.261971-4-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> X-Mailer: git-send-email 2.23.0.866.gb869b98d4c-goog Subject: [PATCH 03/18] arm64: kvm: stop treating register x18 as caller save From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Ard Biesheuvel Cc: Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sami Tolvanen Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ard Biesheuvel In preparation of using x18 as a task struct pointer register when running in the kernel, stop treating it as caller save in the KVM guest entry/exit code. Currently, the code assumes there is no need to preserve it for the host, given that it would have been assumed clobbered anyway by the function call to __guest_enter(). Instead, preserve its value and restore it upon return. Link: https://patchwork.kernel.org/patch/9836891/ Signed-off-by: Ard Biesheuvel Signed-off-by: Sami Tolvanen --- arch/arm64/kvm/hyp/entry.S | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) -- 2.23.0.866.gb869b98d4c-goog diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index e5cc8d66bf53..20bd9a20ea27 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -23,6 +23,7 @@ .pushsection .hyp.text, "ax" .macro save_callee_saved_regs ctxt + str x18, [\ctxt, #CPU_XREG_OFFSET(18)] stp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)] stp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)] stp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)] @@ -38,6 +39,7 @@ ldp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)] ldp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)] ldp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)] + ldr x18, [\ctxt, #CPU_XREG_OFFSET(18)] .endm /* @@ -87,12 +89,9 @@ alternative_else_nop_endif ldp x14, x15, [x18, #CPU_XREG_OFFSET(14)] ldp x16, x17, [x18, #CPU_XREG_OFFSET(16)] - // Restore guest regs x19-x29, lr + // Restore guest regs x18-x29, lr restore_callee_saved_regs x18 - // Restore guest reg x18 - ldr x18, [x18, #CPU_XREG_OFFSET(18)] - // Do not touch any register after this! eret sb @@ -114,7 +113,7 @@ ENTRY(__guest_exit) // Retrieve the guest regs x0-x1 from the stack ldp x2, x3, [sp], #16 // x0, x1 - // Store the guest regs x0-x1 and x4-x18 + // Store the guest regs x0-x1 and x4-x17 stp x2, x3, [x1, #CPU_XREG_OFFSET(0)] stp x4, x5, [x1, #CPU_XREG_OFFSET(4)] stp x6, x7, [x1, #CPU_XREG_OFFSET(6)] @@ -123,9 +122,8 @@ ENTRY(__guest_exit) stp x12, x13, [x1, #CPU_XREG_OFFSET(12)] stp x14, x15, [x1, #CPU_XREG_OFFSET(14)] stp x16, x17, [x1, #CPU_XREG_OFFSET(16)] - str x18, [x1, #CPU_XREG_OFFSET(18)] - // Store the guest regs x19-x29, lr + // Store the guest regs x18-x29, lr save_callee_saved_regs x1 get_host_ctxt x2, x3