hostmem-memfd: add checks before adding hostmem-memfd & properties
Run some memfd-related checks before registering hostmem-memfd &
various properties. This will help libvirt to figure out what the host
is supposed to be capable of.
qemu_memfd_check() is changed to a less optimized version, since it is
used with various flags, it no longer caches the result.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180906161415.8543-1-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index 1e20fe0..3800bd0 100644
--- a/backends/hostmem-memfd.c
+++ b/backends/hostmem-memfd.c
@@ -140,18 +140,22 @@
bc->alloc = memfd_backend_memory_alloc;
- object_class_property_add_bool(oc, "hugetlb",
- memfd_backend_get_hugetlb,
- memfd_backend_set_hugetlb,
- &error_abort);
- object_class_property_add(oc, "hugetlbsize", "int",
- memfd_backend_get_hugetlbsize,
- memfd_backend_set_hugetlbsize,
- NULL, NULL, &error_abort);
- object_class_property_add_bool(oc, "seal",
- memfd_backend_get_seal,
- memfd_backend_set_seal,
- &error_abort);
+ if (qemu_memfd_check(MFD_HUGETLB)) {
+ object_class_property_add_bool(oc, "hugetlb",
+ memfd_backend_get_hugetlb,
+ memfd_backend_set_hugetlb,
+ &error_abort);
+ object_class_property_add(oc, "hugetlbsize", "int",
+ memfd_backend_get_hugetlbsize,
+ memfd_backend_set_hugetlbsize,
+ NULL, NULL, &error_abort);
+ }
+ if (qemu_memfd_check(MFD_ALLOW_SEALING)) {
+ object_class_property_add_bool(oc, "seal",
+ memfd_backend_get_seal,
+ memfd_backend_set_seal,
+ &error_abort);
+ }
}
static const TypeInfo memfd_backend_info = {
@@ -164,7 +168,9 @@
static void register_types(void)
{
- type_register_static(&memfd_backend_info);
+ if (qemu_memfd_check(0)) {
+ type_register_static(&memfd_backend_info);
+ }
}
type_init(register_types);
diff --git a/include/qemu/memfd.h b/include/qemu/memfd.h
index 49e7963..d551c28 100644
--- a/include/qemu/memfd.h
+++ b/include/qemu/memfd.h
@@ -16,12 +16,28 @@
#define F_SEAL_WRITE 0x0008 /* prevent writes */
#endif
+#ifndef MFD_CLOEXEC
+#define MFD_CLOEXEC 0x0001U
+#endif
+
+#ifndef MFD_ALLOW_SEALING
+#define MFD_ALLOW_SEALING 0x0002U
+#endif
+
+#ifndef MFD_HUGETLB
+#define MFD_HUGETLB 0x0004U
+#endif
+
+#ifndef MFD_HUGE_SHIFT
+#define MFD_HUGE_SHIFT 26
+#endif
+
int qemu_memfd_create(const char *name, size_t size, bool hugetlb,
uint64_t hugetlbsize, unsigned int seals, Error **errp);
bool qemu_memfd_alloc_check(void);
void *qemu_memfd_alloc(const char *name, size_t size, unsigned int seals,
int *fd, Error **errp);
void qemu_memfd_free(void *ptr, size_t size, int fd);
-bool qemu_memfd_check(void);
+bool qemu_memfd_check(unsigned int flags);
#endif /* QEMU_MEMFD_H */
diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
index 716aff7..45d58d8 100644
--- a/tests/vhost-user-test.c
+++ b/tests/vhost-user-test.c
@@ -169,7 +169,7 @@
int mem, enum test_memfd memfd, const char *mem_path,
const char *chr_opts, const char *extra)
{
- if (memfd == TEST_MEMFD_AUTO && qemu_memfd_check()) {
+ if (memfd == TEST_MEMFD_AUTO && qemu_memfd_check(0)) {
memfd = TEST_MEMFD_YES;
}
@@ -903,7 +903,7 @@
s->queues = 2;
test_server_listen(s);
- if (qemu_memfd_check()) {
+ if (qemu_memfd_check(0)) {
cmd = g_strdup_printf(
QEMU_CMD_MEMFD QEMU_CMD_CHR QEMU_CMD_NETDEV ",queues=%d "
"-device virtio-net-pci,netdev=net0,mq=on,vectors=%d",
@@ -963,7 +963,7 @@
/* run the main loop thread so the chardev may operate */
thread = g_thread_new(NULL, thread_function, loop);
- if (qemu_memfd_check()) {
+ if (qemu_memfd_check(0)) {
qtest_add_data_func("/vhost-user/read-guest-mem/memfd",
GINT_TO_POINTER(TEST_MEMFD_YES),
test_read_guest_mem);
diff --git a/util/memfd.c b/util/memfd.c
index 6287946..8debd0d 100644
--- a/util/memfd.c
+++ b/util/memfd.c
@@ -45,22 +45,6 @@
}
#endif
-#ifndef MFD_CLOEXEC
-#define MFD_CLOEXEC 0x0001U
-#endif
-
-#ifndef MFD_ALLOW_SEALING
-#define MFD_ALLOW_SEALING 0x0002U
-#endif
-
-#ifndef MFD_HUGETLB
-#define MFD_HUGETLB 0x0004U
-#endif
-
-#ifndef MFD_HUGE_SHIFT
-#define MFD_HUGE_SHIFT 26
-#endif
-
int qemu_memfd_create(const char *name, size_t size, bool hugetlb,
uint64_t hugetlbsize, unsigned int seals, Error **errp)
{
@@ -201,23 +185,16 @@
*
* Check if host supports memfd.
*/
-bool qemu_memfd_check(void)
+bool qemu_memfd_check(unsigned int flags)
{
#ifdef CONFIG_LINUX
- static int memfd_check = MEMFD_TODO;
+ int mfd = memfd_create("test", flags);
- if (memfd_check == MEMFD_TODO) {
- int mfd = memfd_create("test", 0);
- if (mfd >= 0) {
- memfd_check = MEMFD_OK;
- close(mfd);
- } else {
- memfd_check = MEMFD_KO;
- }
+ if (mfd >= 0) {
+ close(mfd);
+ return true;
}
-
- return memfd_check == MEMFD_OK;
-#else
- return false;
#endif
+
+ return false;
}
