From patchwork Tue Jun 16 10:26:34 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 484937 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id EA74F14027F for ; Tue, 16 Jun 2015 20:45:21 +1000 (AEST) Received: from localhost ([::1]:39256 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4oMp-0002Ew-Sz for incoming@patchwork.ozlabs.org; Tue, 16 Jun 2015 06:45:19 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53624) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4o5x-0006tR-GG for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:27:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z4o5v-00016Y-Ib for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:27:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56685) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4o5v-00015z-8L for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:27:51 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id E4D93C9446; Tue, 16 Jun 2015 10:27:50 +0000 (UTC) Received: from dgilbert-t530.redhat.com (ovpn-116-112.ams2.redhat.com [10.36.116.112]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t5GAQta6017611; Tue, 16 Jun 2015 06:27:48 -0400 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org Date: Tue, 16 Jun 2015 11:26:34 +0100 Message-Id: <1434450415-11339-22-git-send-email-dgilbert@redhat.com> In-Reply-To: <1434450415-11339-1-git-send-email-dgilbert@redhat.com> References: <1434450415-11339-1-git-send-email-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, quintela@redhat.com, liang.z.li@intel.com, luis@cs.umu.se, amit.shah@redhat.com, pbonzini@redhat.com, david@gibson.dropbear.id.au Subject: [Qemu-devel] [PATCH v7 21/42] postcopy: OS support test X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: "Dr. David Alan Gilbert" Provide a check to see if the OS we're running on has all the bits needed for postcopy. Creates postcopy-ram.c which will get most of the other helpers we need. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Reviewed-by: Amit Shah --- include/migration/postcopy-ram.h | 19 +++++ migration/Makefile.objs | 2 +- migration/postcopy-ram.c | 158 +++++++++++++++++++++++++++++++++++++++ migration/savevm.c | 5 ++ 4 files changed, 183 insertions(+), 1 deletion(-) create mode 100644 include/migration/postcopy-ram.h create mode 100644 migration/postcopy-ram.c diff --git a/include/migration/postcopy-ram.h b/include/migration/postcopy-ram.h new file mode 100644 index 0000000..d81934f --- /dev/null +++ b/include/migration/postcopy-ram.h @@ -0,0 +1,19 @@ +/* + * Postcopy migration for RAM + * + * Copyright 2013 Red Hat, Inc. and/or its affiliates + * + * Authors: + * Dave Gilbert + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + */ +#ifndef QEMU_POSTCOPY_RAM_H +#define QEMU_POSTCOPY_RAM_H + +/* Return true if the host supports everything we need to do postcopy-ram */ +bool postcopy_ram_supported_by_host(void); + +#endif diff --git a/migration/Makefile.objs b/migration/Makefile.objs index d929e96..0cac6d7 100644 --- a/migration/Makefile.objs +++ b/migration/Makefile.objs @@ -1,7 +1,7 @@ common-obj-y += migration.o tcp.o common-obj-y += vmstate.o common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o -common-obj-y += xbzrle.o +common-obj-y += xbzrle.o postcopy-ram.o common-obj-$(CONFIG_RDMA) += rdma.o common-obj-$(CONFIG_POSIX) += exec.o unix.o fd.o diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c new file mode 100644 index 0000000..baf83f2 --- /dev/null +++ b/migration/postcopy-ram.c @@ -0,0 +1,158 @@ +/* + * Postcopy migration for RAM + * + * Copyright 2013-2015 Red Hat, Inc. and/or its affiliates + * + * Authors: + * Dave Gilbert + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + */ + +/* + * Postcopy is a migration technique where the execution flips from the + * source to the destination before all the data has been copied. + */ + +#include +#include +#include + +#include "qemu-common.h" +#include "migration/migration.h" +#include "migration/postcopy-ram.h" +#include "sysemu/sysemu.h" +#include "qemu/error-report.h" +#include "trace.h" + +/* Postcopy needs to detect accesses to pages that haven't yet been copied + * across, and efficiently map new pages in, the techniques for doing this + * are target OS specific. + */ +#if defined(__linux__) + +#include +#include +#include +#include +#include /* for __u64 */ +#endif + +#if defined(__linux__) && defined(__NR_userfaultfd) +#include + +static bool ufd_version_check(int ufd) +{ + struct uffdio_api api_struct; + uint64_t ioctl_mask; + + api_struct.api = UFFD_API; + api_struct.features = 0; + if (ioctl(ufd, UFFDIO_API, &api_struct)) { + error_report("postcopy_ram_supported_by_host: UFFDIO_API failed: %s", + strerror(errno)); + return false; + } + + ioctl_mask = (__u64)1 << _UFFDIO_REGISTER | + (__u64)1 << _UFFDIO_UNREGISTER; + if ((api_struct.ioctls & ioctl_mask) != ioctl_mask) { + error_report("Missing userfault features: %" PRIx64, + (uint64_t)(~api_struct.ioctls & ioctl_mask)); + return false; + } + + return true; +} + +bool postcopy_ram_supported_by_host(void) +{ + long pagesize = getpagesize(); + int ufd = -1; + bool ret = false; /* Error unless we change it */ + void *testarea = NULL; + struct uffdio_register reg_struct; + struct uffdio_range range_struct; + uint64_t feature_mask; + + if ((1ul << qemu_target_page_bits()) > pagesize) { + error_report("Target page size bigger than host page size"); + goto out; + } + + ufd = syscall(__NR_userfaultfd, O_CLOEXEC); + if (ufd == -1) { + error_report("%s: userfaultfd not available: %s", __func__, + strerror(errno)); + goto out; + } + + /* Version and features check */ + if (!ufd_version_check(ufd)) { + goto out; + } + + /* + * We need to check that the ops we need are supported on anon memory + * To do that we need to register a chunk and see the flags that + * are returned. + */ + testarea = mmap(NULL, pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE | + MAP_ANONYMOUS, -1, 0); + if (testarea == MAP_FAILED) { + error_report("%s: Failed to map test area: %s", __func__, + strerror(errno)); + goto out; + } + g_assert(((size_t)testarea & (pagesize-1)) == 0); + + reg_struct.range.start = (uintptr_t)testarea; + reg_struct.range.len = pagesize; + reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING; + + if (ioctl(ufd, UFFDIO_REGISTER, ®_struct)) { + error_report("%s userfault register: %s", __func__, strerror(errno)); + goto out; + } + + range_struct.start = (uintptr_t)testarea; + range_struct.len = pagesize; + if (ioctl(ufd, UFFDIO_UNREGISTER, &range_struct)) { + error_report("%s userfault unregister: %s", __func__, strerror(errno)); + goto out; + } + + feature_mask = (__u64)1 << _UFFDIO_WAKE | + (__u64)1 << _UFFDIO_COPY | + (__u64)1 << _UFFDIO_ZEROPAGE; + if ((reg_struct.ioctls & feature_mask) != feature_mask) { + error_report("Missing userfault map features: %" PRIx64, + (uint64_t)(~reg_struct.ioctls & feature_mask)); + goto out; + } + + /* Success! */ + ret = true; +out: + if (testarea) { + munmap(testarea, pagesize); + } + if (ufd != -1) { + close(ufd); + } + return ret; +} + +#else +/* No target OS support, stubs just fail */ + +bool postcopy_ram_supported_by_host(void) +{ + error_report("%s: No OS support", __func__); + return false; +} + +#endif + diff --git a/migration/savevm.c b/migration/savevm.c index ebd3d31..f324c6e 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -37,6 +37,7 @@ #include "qemu/timer.h" #include "audio/audio.h" #include "migration/migration.h" +#include "migration/postcopy-ram.h" #include "qemu/sockets.h" #include "qemu/queue.h" #include "sysemu/cpus.h" @@ -1165,6 +1166,10 @@ static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis, return -1; } + if (!postcopy_ram_supported_by_host()) { + return -1; + } + if (remote_hps != getpagesize()) { /* * Some combinations of mismatch are probably possible but it gets