From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50084) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yi4H7-0006xC-14 for qemu-devel@nongnu.org; Tue, 14 Apr 2015 13:05:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yi4H4-0002mZ-7f for qemu-devel@nongnu.org; Tue, 14 Apr 2015 13:05:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33316) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yi4H4-0002m3-0o for qemu-devel@nongnu.org; Tue, 14 Apr 2015 13:05:22 -0400 From: "Dr. David Alan Gilbert (git)" Date: Tue, 14 Apr 2015 18:03:51 +0100 Message-Id: <1429031053-4454-26-git-send-email-dgilbert@redhat.com> In-Reply-To: <1429031053-4454-1-git-send-email-dgilbert@redhat.com> References: <1429031053-4454-1-git-send-email-dgilbert@redhat.com> Subject: [Qemu-devel] [PATCH v6 25/47] postcopy: OS support test List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, quintela@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, david@gibson.dropbear.id.au, yayanghy@cn.fujitsu.com 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 --- include/migration/postcopy-ram.h | 19 +++++ migration/Makefile.objs | 2 +- migration/postcopy-ram.c | 157 +++++++++++++++++++++++++++++++++++++++ savevm.c | 5 ++ 4 files changed, 182 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..7704bc1 --- /dev/null +++ b/migration/postcopy-ram.c @@ -0,0 +1,157 @@ +/* + * 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 feature_mask; + + api_struct.api = UFFD_API; + if (ioctl(ufd, UFFDIO_API, &api_struct)) { + error_report("postcopy_ram_supported_by_host: UFFDIO_API failed: %s", + strerror(errno)); + return false; + } + + feature_mask = (__u64)1 << _UFFDIO_REGISTER | + (__u64)1 << _UFFDIO_UNREGISTER; + if ((api_struct.ioctls & feature_mask) != feature_mask) { + error_report("Missing userfault features: %" PRIx64, + (uint64_t)(~api_struct.ioctls & feature_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/savevm.c b/savevm.c index 79bbded..23cc99e 100644 --- a/savevm.c +++ b/savevm.c @@ -33,6 +33,7 @@ #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" @@ -1113,6 +1114,10 @@ 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 -- 2.1.0