This splits the read/write functions into top and bottom halves. It doesn't
change much yet, but this is a requirement for async IO. The start funtion
turns the request into an ioinfo (to be completed eventually by a thread) and
the finish function retrives the result. (for now, we just do the work in
finish.)
seems to work, but could probably use a little more load testing.
Index: virtio.c
===================================================================
RCS file: /cvs/src/usr.sbin/vmd/virtio.c,v
retrieving revision 1.47
diff -u -p -r1.47 virtio.c
--- virtio.c 27 May 2017 23:58:16 -0000 1.47
+++ virtio.c 30 May 2017 10:56:47 -0000
@@ -62,6 +62,14 @@ int nr_vioblk;
#define VMMCI_F_ACK (1<<1)
#define VMMCI_F_SYNCRTC (1<<2)
+struct ioinfo {
+ uint8_t *buf;
+ ssize_t len;
+ off_t offset;
+ int fd;
+ int error;
+};
+
const char *
vioblk_cmd_name(uint32_t type)
{
@@ -324,35 +332,87 @@ vioblk_update_qs(struct vioblk_dev *dev)
dev->cfg.queue_size = dev->vq[dev->cfg.queue_select].qs;
}
-static char *
-vioblk_do_read(struct vioblk_dev *dev, off_t sector, ssize_t sz)
+static void
+vioblk_free_info(struct ioinfo *info)
{
- char *buf;
+ if (!info)
+ return;
+ free(info->buf);
+ free(info);
+}
- buf = malloc(sz);
- if (buf == NULL) {
- log_warn("malloc errror vioblk read");
- return (NULL);
- }
+static struct ioinfo *
+vioblk_start_read(struct vioblk_dev *dev, off_t sector, ssize_t sz)
+{
+ struct ioinfo *info;
+
+ info = calloc(1, sizeof(*info));
+ if (!info)
+ goto nomem;
+ info->buf = malloc(sz);
+ if (info->buf == NULL)
+ goto nomem;
+ info->len = sz;
+ info->offset = sector * VIRTIO_BLK_SECTOR_SIZE;
+ info->fd = dev->fd;
+
+ return info;
- if (pread(dev->fd, buf, sz, sector * VIRTIO_BLK_SECTOR_SIZE) != sz) {
+nomem:
+ free(info);
+ log_warn("malloc errror vioblk read");
+ return (NULL);
+}
+
+
+static const uint8_t *
+vioblk_finish_read(struct ioinfo *info)
+{
+ if (pread(info->fd, info->buf, info->len, info->offset) != info->len) {
+ info->error = errno;
log_warn("vioblk read error");
- free(buf);
- return (NULL);
+ return NULL;
}
- return buf;
+ return info->buf;
+}
+
+static struct ioinfo *
+vioblk_start_write(struct vioblk_dev *dev, off_t sector, paddr_t addr, size_t
len)
+{
+ struct ioinfo *info;
+
+ info = calloc(1, sizeof(*info));
+ if (!info)
+ goto nomem;
+ info->buf = malloc(len);
+ if (info->buf == NULL)
+ goto nomem;
+ info->len = len;
+ info->offset = sector * VIRTIO_BLK_SECTOR_SIZE;
+ info->fd = dev->fd;
+
+ if (read_mem(addr, info->buf, len)) {
+ vioblk_free_info(info);
+ return NULL;
+ }
+
+ return info;
+
+nomem:
+ free(info);
+ log_warn("malloc errror vioblk write");
+ return (NULL);
}
static int
-vioblk_do_write(struct vioblk_dev *dev, off_t sector, char *buf, ssize_t sz)
+vioblk_finish_write(struct ioinfo *info)
{
- if (pwrite(dev->fd, buf, sz, sector * VIRTIO_BLK_SECTOR_SIZE) != sz) {
+ if (pwrite(info->fd, info->buf, info->len, info->offset) != info->len) {
log_warn("vioblk write error");
- return (1);
+ return EIO;
}
-
- return (0);
+ return 0;
}
/*
@@ -368,7 +428,7 @@ vioblk_notifyq(struct vioblk_dev *dev)
uint8_t ds;
int ret;
off_t secbias;
- char *vr, *secdata;
+ char *vr;
struct vring_desc *desc, *cmd_desc, *secdata_desc, *ds_desc;
struct vring_avail *avail;
struct vring_used *used;
@@ -441,14 +501,16 @@ vioblk_notifyq(struct vioblk_dev *dev)
secbias = 0;
do {
- /* read the data (use current data descriptor)
*/
- /*
- * XXX waste to malloc secdata in vioblk_do_read
- * and free it here over and over
- */
- secdata = vioblk_do_read(dev, cmd.sector +
secbias,
+ struct ioinfo *info;
+ const uint8_t *secdata;
+
+ info = vioblk_start_read(dev, cmd.sector +
secbias,
(ssize_t)secdata_desc->len);
+
+ /* read the data (use current data descriptor)
*/
+ secdata = vioblk_finish_read(info);
if (secdata == NULL) {
+ vioblk_free_info(info);
log_warnx("vioblk: block read error, "
"sector %lld", cmd.sector);
goto out;
@@ -460,11 +522,11 @@ vioblk_notifyq(struct vioblk_dev *dev)
"data to gpa @ 0x%llx",
secdata_desc->addr);
dump_descriptor_chain(desc,
cmd_desc_idx);
- free(secdata);
+ vioblk_free_info(info);
goto out;
}
- free(secdata);
+ vioblk_free_info(info);
secbias += (secdata_desc->len /
VIRTIO_BLK_SECTOR_SIZE);
secdata_desc_idx = secdata_desc->next &
@@ -514,35 +576,31 @@ vioblk_notifyq(struct vioblk_dev *dev)
goto out;
}
- secdata = NULL;
secbias = 0;
do {
- secdata = realloc(secdata, secdata_desc->len);
- if (secdata == NULL) {
- log_warn("wr vioblk: malloc error, "
- "len %d", secdata_desc->len);
- goto out;
- }
+ struct ioinfo *info;
- if (read_mem(secdata_desc->addr, secdata,
- secdata_desc->len)) {
+ info = vioblk_start_write(dev, cmd.sector +
secbias,
+ secdata_desc->addr, secdata_desc->len);
+
+ if (info == NULL) {
log_warnx("wr vioblk: can't read "
"sector data @ 0x%llx",
secdata_desc->addr);
dump_descriptor_chain(desc,
cmd_desc_idx);
- free(secdata);
goto out;
}
- if (vioblk_do_write(dev, cmd.sector + secbias,
- secdata, (ssize_t)secdata_desc->len)) {
+ if (vioblk_finish_write(info)) {
log_warnx("wr vioblk: disk write "
"error");
- free(secdata);
+ vioblk_free_info(info);
goto out;
}
+ vioblk_free_info(info);
+
secbias += secdata_desc->len /
VIRTIO_BLK_SECTOR_SIZE;
@@ -550,8 +608,6 @@ vioblk_notifyq(struct vioblk_dev *dev)
VIOBLK_QUEUE_MASK;
secdata_desc = &desc[secdata_desc_idx];
} while (secdata_desc->flags & VRING_DESC_F_NEXT);
-
- free(secdata);
ds_desc_idx = secdata_desc_idx;
ds_desc = secdata_desc;
Index: vm.c
===================================================================
RCS file: /cvs/src/usr.sbin/vmd/vm.c,v
retrieving revision 1.18
diff -u -p -r1.18 vm.c
--- vm.c 28 May 2017 23:56:13 -0000 1.18
+++ vm.c 30 May 2017 10:54:53 -0000
@@ -1230,9 +1230,10 @@ find_gpa_range(struct vm_create_params *
* exist in the guest.
*/
int
-write_mem(paddr_t dst, void *buf, size_t len)
+write_mem(paddr_t dst, const void *buf, size_t len)
{
- char *from = buf, *to;
+ const char *from = buf;
+ char *to;
size_t n, off;
struct vm_mem_range *vmr;
Index: vmd.h
===================================================================
RCS file: /cvs/src/usr.sbin/vmd/vmd.h,v
retrieving revision 1.54
diff -u -p -r1.54 vmd.h
--- vmd.h 4 May 2017 19:41:58 -0000 1.54
+++ vmd.h 30 May 2017 10:55:05 -0000
@@ -289,7 +289,7 @@ uint32_t vm_priv_addr(struct address *,
/* vmm.c */
void vmm(struct privsep *, struct privsep_proc *);
void vmm_shutdown(void);
-int write_mem(paddr_t, void *buf, size_t);
+int write_mem(paddr_t, const void *buf, size_t);
int read_mem(paddr_t, void *buf, size_t);
int opentap(char *);
int fd_hasdata(int);
