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[PATCH v2 2/8] libvhost-user: replace qemu/memfd.h usage
From: |
marcandre . lureau |
Subject: |
[PATCH v2 2/8] libvhost-user: replace qemu/memfd.h usage |
Date: |
Wed, 25 Nov 2020 14:06:34 +0400 |
From: Marc-André Lureau <marcandre.lureau@redhat.com>
Undo the damage from commit 5f9ff1eff3 ("libvhost-user: Support tracking
inflight I/O in shared memory") which introduced glib dependency through
osdep.h inclusion.
libvhost-user.c tries to stay free from glib usage.
Use glibc memfd_create directly when available (assumed so when
MFD_ALLOW_SEALING is defined). A following commit will make the project
standalone and check for memfd API at configure time, instead of a
panic at runtime.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
contrib/libvhost-user/libvhost-user.c | 50 +++++++++++++++++++++++----
1 file changed, 43 insertions(+), 7 deletions(-)
diff --git a/contrib/libvhost-user/libvhost-user.c
b/contrib/libvhost-user/libvhost-user.c
index 1c1cfbf1e7..54aabd1878 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -42,8 +42,6 @@
#endif
#include "qemu/atomic.h"
-#include "qemu/osdep.h"
-#include "qemu/memfd.h"
#include "libvhost-user.h"
@@ -1615,11 +1613,45 @@ vu_inflight_queue_size(uint16_t queue_size)
sizeof(uint16_t), INFLIGHT_ALIGNMENT);
}
+#ifdef MFD_ALLOW_SEALING
+static void *
+memfd_alloc(const char *name, size_t size, unsigned int flags, int *fd)
+{
+ void *ptr;
+ int ret;
+
+ *fd = memfd_create(name, MFD_ALLOW_SEALING);
+ if (*fd < 0) {
+ return NULL;
+ }
+
+ ret = ftruncate(*fd, size);
+ if (ret < 0) {
+ close(*fd);
+ return NULL;
+ }
+
+ ret = fcntl(*fd, F_ADD_SEALS, flags);
+ if (ret < 0) {
+ close(*fd);
+ return NULL;
+ }
+
+ ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, *fd, 0);
+ if (ptr == MAP_FAILED) {
+ close(*fd);
+ return NULL;
+ }
+
+ return ptr;
+}
+#endif
+
static bool
vu_get_inflight_fd(VuDev *dev, VhostUserMsg *vmsg)
{
- int fd;
- void *addr;
+ int fd = -1;
+ void *addr = NULL;
uint64_t mmap_size;
uint16_t num_queues, queue_size;
@@ -1637,9 +1669,13 @@ vu_get_inflight_fd(VuDev *dev, VhostUserMsg *vmsg)
mmap_size = vu_inflight_queue_size(queue_size) * num_queues;
- addr = qemu_memfd_alloc("vhost-inflight", mmap_size,
- F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
- &fd, NULL);
+#ifdef MFD_ALLOW_SEALING
+ addr = memfd_alloc("vhost-inflight", mmap_size,
+ F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
+ &fd);
+#else
+ vu_panic(dev, "Not implemented: memfd support is missing");
+#endif
if (!addr) {
vu_panic(dev, "Failed to alloc vhost inflight area");
--
2.29.0
- [PATCH v2 0/8] libvhost-user: make it a subproject (was: "lower dependency on QEMU headers"), marcandre . lureau, 2020/11/25
- [PATCH v2 1/8] libvhost-user: replace qemu/bswap.h with glibc endian.h, marcandre . lureau, 2020/11/25
- [PATCH v2 2/8] libvhost-user: replace qemu/memfd.h usage,
marcandre . lureau <=
- [PATCH v2 3/8] libvhost-user: remove qemu/compiler.h usage, marcandre . lureau, 2020/11/25
- [PATCH v2 4/8] libvhost-user: drop qemu/osdep.h dependency, marcandre . lureau, 2020/11/25
- [PATCH v2 5/8] libvhost-user: make it a meson subproject, marcandre . lureau, 2020/11/25
- [PATCH v2 6/8] libvhost-user: check memfd API, marcandre . lureau, 2020/11/25
- [PATCH v2 7/8] libvhost-user: add a simple link test without glib, marcandre . lureau, 2020/11/25
- [PATCH v2 8/8] .gitlab-ci: add build-libvhost-user, marcandre . lureau, 2020/11/25