From patchwork Mon Mar 4 20:52:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 159623 Delivered-To: patch@linaro.org Received: by 2002:a02:5cc1:0:0:0:0:0 with SMTP id w62csp4199221jad; Mon, 4 Mar 2019 12:54:10 -0800 (PST) X-Google-Smtp-Source: APXvYqzJafLMQ8iiZdM/IUbqpBskj8MHu3TKo0/MOjcQsUl1aGXYZ6APbXblBWLUGJGIzPlO8XHc X-Received: by 2002:a63:8542:: with SMTP id u63mr20329759pgd.323.1551732850657; Mon, 04 Mar 2019 12:54:10 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1551732850; cv=none; d=google.com; s=arc-20160816; b=kzL7khYnsUYYYOFCL7CgFYwQXhHrhStNdWe2PRbdRKItJP4P5m1fdE5h3KE/s6JIBE Gr7KXWxt2cqQpH7GKb/xFeeTor1HZhbPM5h2tOQJNU4mJCvLdl/dh0pPJZGwv9TMvUU/ tMQIioUygFN8hcXJsM3CWGi08PRAYgtRziTl4wDK0uazDNNgBibmRDvrCPo2EzPujO4/ I5iqdhGpeEOrzKwTymdGbn7ZeXBAMrpKYwV0v+esCYtxoe55jrK2JpQjksHEU1v+TVVh yKM0Xdt9Ni+v0qXUeJO698GG0mv0BV9koRYyUVYWmsQzRRTgeT4l6lhL3IJPbrgq7uWq QNyA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from; bh=Kf643Rye9f/k6IZMKRxViyKoj1m8hfeIRZjtYq+5iIw=; b=TEV0CcaOMpngmPrV5nZUny+lTgYh+WJAl1BPVHDCBkvJan7XGj6aXOP80YHiiLypkX 1azvm/jLtrw6h6FmygqCgbTUOgkBTrhyZbdNbjgpPWiV+/HItR59adB1FrRWQuFEp0Ba vYWGOH1a5tgZRTj56fdnf9O+HDfohBRWi/AxMIeD3NW5U2sTR+CVo/WHJxR92DOeG8Qs 91ie81lguZaKhcpE9qCKmiBJ1G8CFvUVHTo1KNRIgO60mHI4wz8nVyk8l39zsK81Qjmy oS/gYalOgtmEJ+LhPjTg3cnh+jnEcs0Wq4u4bzPFuJDHKYpYmNtp5zbsfU/AUGJ1ovS6 wuxw== ARC-Authentication-Results: i=1; mx.google.com; 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 Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p25si5972302pff.77.2019.03.04.12.54.10; Mon, 04 Mar 2019 12:54:10 -0800 (PST) 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; 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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726473AbfCDUyJ (ORCPT + 31 others); Mon, 4 Mar 2019 15:54:09 -0500 Received: from mout.kundenserver.de ([212.227.17.10]:59253 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726111AbfCDUyI (ORCPT ); Mon, 4 Mar 2019 15:54:08 -0500 Received: from wuerfel.lan ([109.192.41.194]) by mrelayeu.kundenserver.de (mreue109 [212.227.15.145]) with ESMTPA (Nemesis) id 1MZCSt-1gVvSC0xV3-00V9kK; Mon, 04 Mar 2019 21:53:05 +0100 From: Arnd Bergmann To: Boris Ostrovsky , Juergen Gross , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org Cc: Arnd Bergmann , Jan Beulich , Stefano Stabellini , "H. Peter Anvin" , Jan Beulich , Oleksandr Andrushchenko , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Subject: [PATCH] [RESEND] [v3] xen: remove pre-xen3 fallback handlers Date: Mon, 4 Mar 2019 21:52:39 +0100 Message-Id: <20190304205300.2582076-1-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 X-Provags-ID: V03:K1:QcaSXjLOGR8UcGaIFZsBU5NxjYWgj7CWpwkReQnMNxEjXwyvvqg 12vMoqsMa/xyg2IOoMC1VMD2YkxqxP2XEF4OaJVJgBd5K2/ASEesnS7CAvHag7Md7kF3RZc Nd8DYLsEmHY+62jmnqUfhLKDcsEOaslMhHNwWzDmWYlW+A6/zyLQkGPaN759zVu4qw8CcQO lBNBLNHHbHVxVSrDEXFtA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1; V03:K0:w1Cd9zXSfT8=:v0zgZOs/IsnhQwY4CFsOWy aJPl9OOuVe8EuTH0sUWD2r/xURAv5Dh7djGQ+7deC3a1ZRpZY5Msy00SNrVwQ7y0XEbsX4RfH Tle707rI3DyzgF0FVakX+AyjAPZ7f8Sk3mUHY3w+y/mEWTlVU29BqwvrcRnJCvSqG09FeA+ji Z7T2B0k448VeUGjWdnj33BOcU7oJRHQTNSqvA9V07oYrNzSWHDMf2wcZlY2MQ9xhjjFW6Ro6c iu67ro8K9zxJ+eoEooZRnYRs1x103d2AyLV4sfA4+CFatWLeqH0ovIZgksp6zgs/zt/wu+Yjz EwU1+CMApVwnt+IC8BjPKdh1eBVd/ypoQ15n/5fBvMZlk/frC+k496WlRw9UGXKxUwgHodVae YNON/4NfqZlgVAokL0eA4jt7Kr0ixpRxGtCXwkCBJYEQU7RN+vfKCYowxEI2XwhE2B9WWlUj0 dJcckcxUGAtscQqdj3xdMKwBWuUK3LfUh27+cR3P+hhVzpXVYAGTQA9rD/srn8f4txsfSoBPt ydo+MRAtoV9llhbWymibvtSKAWtj6vWmey4aTZGHSfiKeqW4UrwN+aZAgznvAKcSAljOjni5w 6pZM9Qv12hR6LJd8VVkCZAngWZI5RoyzffqBf1+xRDeYRh9C/Ja4ar/KvxL8t2c64p1sU1c5z Xyqbpw5ESJQ7hcpb9wPSwYnhQXZqI42CjuRfxoMJQtvryGYyKZpnRUQIED7xpxHC4H9Wmerk9 nDyWLWR5dnwYmInMz+JZMkjnXFIgmAXhiaNEAw== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The legacy hypercall handlers were originally added with a comment explaining that "copying the argument structures in HYPERVISOR_event_channel_op() and HYPERVISOR_physdev_op() into the local variable is sufficiently safe" and only made sure to not write past the end of the argument structure, the checks in linux/string.h disagree with that, when link-time optimizations are used: In function 'memcpy', inlined from 'pirq_query_unmask' at drivers/xen/fallback.c:53:2, inlined from '__startup_pirq' at drivers/xen/events/events_base.c:529:2, inlined from 'restore_pirqs' at drivers/xen/events/events_base.c:1439:3, inlined from 'xen_irq_resume' at drivers/xen/events/events_base.c:1581:2: include/linux/string.h:350:3: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter __read_overflow2(); ^ Further research turned out that only Xen 3.0.2 or earlier required the fallback at all, while all versions in use today don't need it. As far as I can tell, it is not even possible to run a mainline kernel on those old Xen releases, at the time when they were in use, only a patched kernel was supported anyway. Fixes: cf47a83fb06e ("xen/hypercall: fix hypercall fallback code for very old hypervisors") Reviewed-by: Boris Ostrovsky Cc: Jan Beulich Signed-off-by: Arnd Bergmann --- [v2] use a table lookup instead of a switch/case statement, after multiple suggestions. [v3] remove that file completely [resend] I just stumbled over this again, the last submission was a year ago, and it seems it never got merged --- arch/x86/include/asm/xen/hypercall.h | 13 +---- drivers/xen/Makefile | 1 - drivers/xen/fallback.c | 81 ---------------------------- 3 files changed, 2 insertions(+), 93 deletions(-) delete mode 100644 drivers/xen/fallback.c -- 2.20.0 diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h index ef05bea7010d..de6f0d59a24f 100644 --- a/arch/x86/include/asm/xen/hypercall.h +++ b/arch/x86/include/asm/xen/hypercall.h @@ -332,15 +332,11 @@ HYPERVISOR_update_va_mapping(unsigned long va, pte_t new_val, return _hypercall4(int, update_va_mapping, va, new_val.pte, new_val.pte >> 32, flags); } -extern int __must_check xen_event_channel_op_compat(int, void *); static inline int HYPERVISOR_event_channel_op(int cmd, void *arg) { - int rc = _hypercall2(int, event_channel_op, cmd, arg); - if (unlikely(rc == -ENOSYS)) - rc = xen_event_channel_op_compat(cmd, arg); - return rc; + return _hypercall2(int, event_channel_op, cmd, arg); } static inline int @@ -355,15 +351,10 @@ HYPERVISOR_console_io(int cmd, int count, char *str) return _hypercall3(int, console_io, cmd, count, str); } -extern int __must_check xen_physdev_op_compat(int, void *); - static inline int HYPERVISOR_physdev_op(int cmd, void *arg) { - int rc = _hypercall2(int, physdev_op, cmd, arg); - if (unlikely(rc == -ENOSYS)) - rc = xen_physdev_op_compat(cmd, arg); - return rc; + return _hypercall2(int, physdev_op, cmd, arg); } static inline int diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile index 5df6d21142f2..7124f9e749b4 100644 --- a/drivers/xen/Makefile +++ b/drivers/xen/Makefile @@ -1,6 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o -obj-$(CONFIG_X86) += fallback.o obj-y += grant-table.o features.o balloon.o manage.o preempt.o time.o obj-y += mem-reservation.o obj-y += events/ diff --git a/drivers/xen/fallback.c b/drivers/xen/fallback.c deleted file mode 100644 index b04fb64c5a91..000000000000 --- a/drivers/xen/fallback.c +++ /dev/null @@ -1,81 +0,0 @@ -#include -#include -#include -#include -#include -#include - -int xen_event_channel_op_compat(int cmd, void *arg) -{ - struct evtchn_op op; - int rc; - - op.cmd = cmd; - memcpy(&op.u, arg, sizeof(op.u)); - rc = _hypercall1(int, event_channel_op_compat, &op); - - switch (cmd) { - case EVTCHNOP_close: - case EVTCHNOP_send: - case EVTCHNOP_bind_vcpu: - case EVTCHNOP_unmask: - /* no output */ - break; - -#define COPY_BACK(eop) \ - case EVTCHNOP_##eop: \ - memcpy(arg, &op.u.eop, sizeof(op.u.eop)); \ - break - - COPY_BACK(bind_interdomain); - COPY_BACK(bind_virq); - COPY_BACK(bind_pirq); - COPY_BACK(status); - COPY_BACK(alloc_unbound); - COPY_BACK(bind_ipi); -#undef COPY_BACK - - default: - WARN_ON(rc != -ENOSYS); - break; - } - - return rc; -} -EXPORT_SYMBOL_GPL(xen_event_channel_op_compat); - -int xen_physdev_op_compat(int cmd, void *arg) -{ - struct physdev_op op; - int rc; - - op.cmd = cmd; - memcpy(&op.u, arg, sizeof(op.u)); - rc = _hypercall1(int, physdev_op_compat, &op); - - switch (cmd) { - case PHYSDEVOP_IRQ_UNMASK_NOTIFY: - case PHYSDEVOP_set_iopl: - case PHYSDEVOP_set_iobitmap: - case PHYSDEVOP_apic_write: - /* no output */ - break; - -#define COPY_BACK(pop, fld) \ - case PHYSDEVOP_##pop: \ - memcpy(arg, &op.u.fld, sizeof(op.u.fld)); \ - break - - COPY_BACK(irq_status_query, irq_status_query); - COPY_BACK(apic_read, apic_op); - COPY_BACK(ASSIGN_VECTOR, irq_op); -#undef COPY_BACK - - default: - WARN_ON(rc != -ENOSYS); - break; - } - - return rc; -} -EXPORT_SYMBOL_GPL(xen_physdev_op_compat);