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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 8D8B8C43381 for ; Mon, 4 Mar 2019 20:54:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5721520663 for ; Mon, 4 Mar 2019 20:54:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726473AbfCDUyJ (ORCPT ); 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 Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:QcaSXjLOGR8UcGaIFZsBU5NxjYWgj7CWpwkReQnMNxEjXwyvvqg 12vMoqsMa/xyg2IOoMC1VMD2YkxqxP2XEF4OaJVJgBd5K2/ASEesnS7CAvHag7Md7kF3RZc Nd8DYLsEmHY+62jmnqUfhLKDcsEOaslMhHNwWzDmWYlW+A6/zyLQkGPaN759zVu4qw8CcQO lBNBLNHHbHVxVSrDEXFtA== 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 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); -- 2.20.0