diff options
author | José Pekkarinen <jose.pekkarinen@nokia.com> | 2016-05-18 13:18:31 +0300 |
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committer | José Pekkarinen <jose.pekkarinen@nokia.com> | 2016-05-18 13:42:15 +0300 |
commit | 437fd90c0250dee670290f9b714253671a990160 (patch) | |
tree | b871786c360704244a07411c69fb58da9ead4a06 /qemu/util/memfd.c | |
parent | 5bbd6fe9b8bab2a93e548c5a53b032d1939eec05 (diff) |
These changes are the raw update to qemu-2.6.
Collission happened in the following patches:
migration: do cleanup operation after completion(738df5b9)
Bug fix.(1750c932f86)
kvmclock: add a new function to update env->tsc.(b52baab2)
The code provided by the patches was already in the upstreamed
version.
Change-Id: I3cc11841a6a76ae20887b2e245710199e1ea7f9a
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
Diffstat (limited to 'qemu/util/memfd.c')
-rw-r--r-- | qemu/util/memfd.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/qemu/util/memfd.c b/qemu/util/memfd.c new file mode 100644 index 000000000..7c406914c --- /dev/null +++ b/qemu/util/memfd.c @@ -0,0 +1,162 @@ +/* + * memfd.c + * + * Copyright (c) 2015 Red Hat, Inc. + * + * QEMU library functions on POSIX which are shared between QEMU and + * the QEMU tools. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" + +#include <glib.h> +#include <glib/gprintf.h> + +#include <sys/mman.h> + +#include "qemu/memfd.h" + +#ifdef CONFIG_MEMFD +#include <sys/memfd.h> +#elif defined CONFIG_LINUX +#include <sys/syscall.h> +#include <asm/unistd.h> + +static int memfd_create(const char *name, unsigned int flags) +{ +#ifdef __NR_memfd_create + return syscall(__NR_memfd_create, name, flags); +#else + return -1; +#endif +} +#endif + +#ifndef MFD_CLOEXEC +#define MFD_CLOEXEC 0x0001U +#endif + +#ifndef MFD_ALLOW_SEALING +#define MFD_ALLOW_SEALING 0x0002U +#endif + +/* + * This is a best-effort helper for shared memory allocation, with + * optional sealing. The helper will do his best to allocate using + * memfd with sealing, but may fallback on other methods without + * sealing. + */ +void *qemu_memfd_alloc(const char *name, size_t size, unsigned int seals, + int *fd) +{ + void *ptr; + int mfd = -1; + + *fd = -1; + +#ifdef CONFIG_LINUX + if (seals) { + mfd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC); + } + + if (mfd == -1) { + /* some systems have memfd without sealing */ + mfd = memfd_create(name, MFD_CLOEXEC); + seals = 0; + } +#endif + + if (mfd != -1) { + if (ftruncate(mfd, size) == -1) { + perror("ftruncate"); + close(mfd); + return NULL; + } + + if (seals && fcntl(mfd, F_ADD_SEALS, seals) == -1) { + perror("fcntl"); + close(mfd); + return NULL; + } + } else { + const char *tmpdir = g_get_tmp_dir(); + gchar *fname; + + fname = g_strdup_printf("%s/memfd-XXXXXX", tmpdir); + mfd = mkstemp(fname); + unlink(fname); + g_free(fname); + + if (mfd == -1) { + perror("mkstemp"); + return NULL; + } + + if (ftruncate(mfd, size) == -1) { + perror("ftruncate"); + close(mfd); + return NULL; + } + } + + ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0); + if (ptr == MAP_FAILED) { + perror("mmap"); + close(mfd); + return NULL; + } + + *fd = mfd; + return ptr; +} + +void qemu_memfd_free(void *ptr, size_t size, int fd) +{ + if (ptr) { + munmap(ptr, size); + } + + if (fd != -1) { + close(fd); + } +} + +enum { + MEMFD_KO, + MEMFD_OK, + MEMFD_TODO +}; + +bool qemu_memfd_check(void) +{ + static int memfd_check = MEMFD_TODO; + + if (memfd_check == MEMFD_TODO) { + int fd; + void *ptr; + + ptr = qemu_memfd_alloc("test", 4096, 0, &fd); + memfd_check = ptr ? MEMFD_OK : MEMFD_KO; + qemu_memfd_free(ptr, 4096, fd); + } + + return memfd_check == MEMFD_OK; +} |