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[209.132.180.67]) by mx.google.com with ESMTP id 79si210097pfi.367.2018.03.13.14.08.34; Tue, 13 Mar 2018 14:08:34 -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; 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 S932687AbeCMVIb (ORCPT + 28 others); Tue, 13 Mar 2018 17:08:31 -0400 Received: from mout.kundenserver.de ([217.72.192.73]:50371 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932372AbeCMVI2 (ORCPT ); Tue, 13 Mar 2018 17:08:28 -0400 Received: from wuerfel.lan ([95.208.111.237]) by mrelayeu.kundenserver.de (mreue101 [212.227.15.145]) with ESMTPA (Nemesis) id 0Lch0h-1eFsry1tv5-00k5zX; Tue, 13 Mar 2018 22:07:01 +0100 From: Arnd Bergmann To: Boris Ostrovsky , Juergen Gross Cc: David Laight , Andrew Cooper , xen-devel , Dan Carpenter , Arnd Bergmann , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, David Woodhouse , Stefano Stabellini , linux-kernel@vger.kernel.org Subject: [PATCH] [v3] xen: remove pre-xen3 fallback handlers Date: Tue, 13 Mar 2018 22:06:09 +0100 Message-Id: <20180313210652.3484599-1-arnd@arndb.de> X-Mailer: git-send-email 2.9.0 X-Provags-ID: V03:K0:FiJkuPTAGqIqRCoUm3OPBePsJWAssIxxC3r1Qw3jjuJY9eHoiz/ pSsbIMkYUwgqFafIkMHsXXiIuDRre25DpbRIt1lti6DgM+7lD7jPVU7brQcbrQ2PlCdMdtw Rpam6sEPnoghRtLjQPQQv20p6QUM0Pway0Oq3tmumTIxY9ruep5lOjvJPL/M6mUU2pPIee+ oWlo+d/16MCJtFHG2iaLw== X-UI-Out-Filterresults: notjunk:1; V01:K0:UamoApXJnyc=:nXxSxhJWr9V35P/FcOez4A OOkKNOUW72iso+h4YPrtVgRzbFoXV/TM2plOLCCjHMRsJD06i64RmLfZ1qOOR+h1YavfrnemN aZ0GDr3Utnyws/MFf9Y9S6hOJNysrBjXaKDMwtrvvBg5IrdpqnAp8ZVHP0ihQpcjnSlfDSFGp /95H0KsUobv4AEPBGlI0pePpKzR05YEaNQbXCOAzajNu/PXLf+01zBzjDLobnewC15lbyh7fG C+CzdVGRVn/91mjkuKxizkbW6NAiWXWqFzsUwBgrMprtlFBO8/qkgATbiiOY4UtBRwuxLA0rH 87MVLK7hS/W1/m/Zg0M4Ll1AY1YqxFKVrxItwvZZEq6um436eHy81r+8WUeVO/4+OEpNE9yC/ 8mAG1y0DO/o7Aa4GcK+vnwOhRc64h1r+DnTDp13S+G+QyJqI1ML1LLF8z5Wzxb67/MN0fF6x6 UJux2Yve8XeOKNukf0v8tB1MfRBkk3ucFkRfGR0IuzYhzfG9aJDGv59DZX9IrQvsvZvC+HmOI yMSuUxWcVhCy3J3o74mXS2YF019bVPU9aeolQrAjg9GFsKKhWp9aefbREV2CB5D4A19sswrzf PmDR4A6Y1I/iS+e6sL3VHlV6qF1G+xVWvQzww4/fxrqdJZ4GcFbbl9ymnLc2W+07WrrmPBxUa lKSDub0vdpMNe4RIFOzr3toaUXp2p6Qnw/7Bm3pfz93fD9AcOpAy6dsEzbMhYVmEbYu3U2Cqw sWJi3LRJPK1P+I84pnNHrByXfVr2fUahJh6tNQ== 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") Signed-off-by: Arnd Bergmann --- [v2] use a table lookup instead of a switch/case statement, after multiple suggestions. [v3] remove that file completely --- 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 -- 2.9.0 Reviewed-by: Boris Ostrovsky diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h index bfd882617613..dcf9353a662a 100644 --- a/arch/x86/include/asm/xen/hypercall.h +++ b/arch/x86/include/asm/xen/hypercall.h @@ -365,15 +365,11 @@ 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 @@ -388,15 +384,10 @@ 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 451e833f5931..ea2485069e19 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 += events/ obj-y += xenbus/ 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);