Merge remote-tracking branch 'remotes/kraxel/tags/ui-20190313-pull-request' into...

[mirror_qemu.git] / util / memfd.c

diff --git a/util/memfd.c b/util/memfd.c
index 07d579ea7d9853a2e7b2a987f2ff390bde42bec2..00334e5b218fa4b7ee19ecfab6687a6aaceffe12 100644 (file)
--- a/util/memfd.c
+++ b/util/memfd.c
@@ -40,33 +40,18 @@ static int memfd_create(const char *name, unsigned int flags)
 #ifdef __NR_memfd_create
     return syscall(__NR_memfd_create, name, flags);
 #else
+    errno = ENOSYS;
     return -1;
 #endif
 }
 #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)
 {
     int htsize = hugetlbsize ? ctz64(hugetlbsize) : 0;
 
-    if (htsize && 1 << htsize != hugetlbsize) {
+    if (htsize && 1ULL << htsize != hugetlbsize) {
         error_setg(errp, "Hugepage size must be a power of 2");
         return -1;
     }
@@ -86,14 +71,18 @@ int qemu_memfd_create(const char *name, size_t size, bool hugetlb,
     }
     mfd = memfd_create(name, flags);
     if (mfd < 0) {
+        error_setg_errno(errp, errno,
+                         "failed to create memfd with flags 0x%x", flags);
         goto err;
     }
 
     if (ftruncate(mfd, size) == -1) {
+        error_setg_errno(errp, errno, "failed to resize memfd to %zu", size);
         goto err;
     }
 
     if (seals && fcntl(mfd, F_ADD_SEALS, seals) == -1) {
+        error_setg_errno(errp, errno, "failed to add seals 0x%x", seals);
         goto err;
     }
 
@@ -103,8 +92,9 @@ err:
     if (mfd >= 0) {
         close(mfd);
     }
+#else
+    error_setg_errno(errp, ENOSYS, "failed to create memfd");
 #endif
-    error_setg_errno(errp, errno, "failed to create memfd");
     return -1;
 }
 
@@ -173,7 +163,13 @@ enum {
     MEMFD_TODO
 };
 
-bool qemu_memfd_check(void)
+/**
+ * qemu_memfd_alloc_check():
+ *
+ * Check if qemu_memfd_alloc() can allocate, including using a
+ * fallback implementation when host doesn't support memfd.
+ */
+bool qemu_memfd_alloc_check(void)
 {
     static int memfd_check = MEMFD_TODO;
 
@@ -181,6 +177,7 @@ bool qemu_memfd_check(void)
         int fd;
         void *ptr;
 
+        fd = -1;
         ptr = qemu_memfd_alloc("test", 4096, 0, &fd, NULL);
         memfd_check = ptr ? MEMFD_OK : MEMFD_KO;
         qemu_memfd_free(ptr, 4096, fd);
@@ -188,3 +185,22 @@ bool qemu_memfd_check(void)
 
     return memfd_check == MEMFD_OK;
 }
+
+/**
+ * qemu_memfd_check():
+ *
+ * Check if host supports memfd.
+ */
+bool qemu_memfd_check(unsigned int flags)
+{
+#ifdef CONFIG_LINUX
+    int mfd = memfd_create("test", flags | MFD_CLOEXEC);
+
+    if (mfd >= 0) {
+        close(mfd);
+        return true;
+    }
+#endif
+
+    return false;
+}