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[192.237.175.120]) by mx.google.com with ESMTPS id g65si2427570iof.100.2016.07.20.08.28.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jul 2016 08:28:44 -0700 (PDT) Received-SPF: neutral (google.com: 192.237.175.120 is neither permitted nor denied by best guess record for domain of xen-devel-bounces@lists.xen.org) client-ip=192.237.175.120; Authentication-Results: mx.google.com; spf=neutral (google.com: 192.237.175.120 is neither permitted nor denied by best guess record for domain of xen-devel-bounces@lists.xen.org) smtp.mailfrom=xen-devel-bounces@lists.xen.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bPtO3-00022H-1q; Wed, 20 Jul 2016 15:26:15 +0000 Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bPtO2-00020a-6U for xen-devel@lists.xen.org; Wed, 20 Jul 2016 15:26:14 +0000 Received: from [193.109.254.147] by server-12.bemta-14.messagelabs.com id 08/80-28536-5189F875; Wed, 20 Jul 2016 15:26:13 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrGLMWRWlGSWpSXmKPExsVysyfVTVd0Rn+ 4we2bjBZLPi5mcWD0OLr7N1MAYxRrZl5SfkUCa8a5x0fZCv7xVez8cIK9gXE7dxcjF4eQwCZG ie5Jexi7GDmBnNOMEg2PPEBsNgFNiTufPzGB2CIC0hLXPl8Gq2EWcJB48/EeC4gtLBAv8arpC VicRUBVYtXEaewgNq+Ai8SJQzPA4hICchInj01mBbE5BVwltm14xAyxy0Widfp25gmM3AsYGV YxahSnFpWlFukaGeklFWWmZ5TkJmbm6BoamujlphYXJ6an5iQmFesl5+duYgT6t56BgXEH4+1 LfocYJTmYlER5VUV7w4X4kvJTKjMSizPii0pzUosPMcpwcChJ8FpM7w8XEixKTU+tSMvMAQYa TFqCg0dJhFcHJM1bXJCYW5yZDpE6xagoJc77fhpQQgAkkVGaB9cGC+5LjLJSwryMDAwMQjwFq UW5mSWo8q8YxTkYlYR5jUHG82TmlcBNfwW0mAlo8RwBsMUliQgpqQbGIq9/YXxcp+5MztwXyB 4kZb7guWPhbaO9nj28ltZ74/Se7bXbUWm6a97v+EC1Fd7PHK/Pqs0LeyR+fTO7sSnjG4OU5VP zmtazRpkdVPIUuv24ypUnmeHdPN/riUn6gju33p0ldtzv3xK5xn1rmF76r1m7ssvx7oSFb+T1 Ss6bzayY1BnbyTtFiaU4I9FQi7moOBEA0G/HnmkCAAA= X-Env-Sender: julien.grall@arm.com X-Msg-Ref: server-13.tower-27.messagelabs.com!1469028372!55047882!1 X-Originating-IP: [217.140.101.70] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 8.77; banners=-,-,- X-VirusChecked: Checked Received: (qmail 10001 invoked from network); 20 Jul 2016 15:26:12 -0000 Received: from foss.arm.com (HELO foss.arm.com) (217.140.101.70) by server-13.tower-27.messagelabs.com with SMTP; 20 Jul 2016 15:26:12 -0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ABB93433; Wed, 20 Jul 2016 08:27:22 -0700 (PDT) Received: from e108454-lin.cambridge.arm.com (e108454-lin.cambridge.arm.com [10.1.218.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7E0863F387; Wed, 20 Jul 2016 08:26:11 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xen.org Date: Wed, 20 Jul 2016 16:26:00 +0100 Message-Id: <1469028360-20907-8-git-send-email-julien.grall@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1469028360-20907-1-git-send-email-julien.grall@arm.com> References: <1469028360-20907-1-git-send-email-julien.grall@arm.com> Cc: Julien Grall , sstabellini@kernel.org Subject: [Xen-devel] [PATCH v5 7/7] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" Based on ARM ARM (D4.5.3 in ARM DDI 0486A and B3.12.7 in ARM DDI 0406C.c), a Stage 1 translation error has priority over a Stage 2 translation error. Therefore gva_to_ipa can only fail if another vCPU is playing with the page table. Rather than injecting a custom fault, replay the instruction and let the processor injecting the correct fault. This is fine as Xen is handling all the pending softirqs (see leave_hypervisor_tail) before returning to the guest. One of them is the scheduler which could rescheduled the vCPU. Signed-off-by: Julien Grall Acked-by: Stefano Stabellini --- Changes in v4: - s/reschuled/rescheduled/ in the commit message Changes in v3: - Add Stefano's acked-by Changes in v2: - Update commit message to explain why a guest cannot DoS the hypervisor with it. --- xen/arch/arm/traps.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c index a2eb1da..d7a3e62 100644 --- a/xen/arch/arm/traps.c +++ b/xen/arch/arm/traps.c @@ -2412,7 +2412,7 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs, rc = gva_to_ipa(gva, &gpa, GV2M_READ); if ( rc == -EFAULT ) - goto bad_insn_abort; + return; /* Try again */ } rc = p2m_mem_access_check(gpa, gva, npfec); @@ -2424,7 +2424,6 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs, break; } -bad_insn_abort: inject_iabt_exception(regs, gva, hsr.len); } @@ -2448,7 +2447,7 @@ static void do_trap_data_abort_guest(struct cpu_user_regs *regs, { rc = gva_to_ipa(info.gva, &info.gpa, GV2M_READ); if ( rc == -EFAULT ) - goto bad_data_abort; + return; /* Try again */ } switch ( dabt.dfsc & 0x3f )