[Qemu-devel] [PATCH 1/2] Add "directio" parameter to "-drive"

[Laurent Vivier]

This patch add a new parameter to "-drive"

Using "directio=on" with "-drive" will open the disk image file using
"O_DIRECT".

By default, "directio" is set to "off".

example:

"-drive file=my_disk.qcow2,directio=on"
---
 block-raw.c    |    4 ++++
 block.c        |    2 +-
 block.h        |    1 +
 hw/fdc.c       |    6 +++++-
 hw/ide.c       |    8 ++++++--
 hw/scsi-disk.c |    3 ++-
 hw/sd.c        |   10 +++++++++-
 vl.c           |   26 +++++++++++++++++++++++---
 8 files changed, 51 insertions(+), 9 deletions(-)

Index: qemu/block-raw.c
===================================================================
--- qemu.orig/block-raw.c       2007-11-25 18:10:07.000000000 +0100
+++ qemu/block-raw.c    2007-11-25 18:21:04.000000000 +0100
@@ -107,6 +107,8 @@ static int raw_open(BlockDriverState *bs
     }
     if (flags & BDRV_O_CREAT)
         open_flags |= O_CREAT | O_TRUNC;
+    if (flags & BDRV_O_DIRECT)
+        open_flags |= O_DIRECT;
 
     s->type = FTYPE_FILE;
 
@@ -660,6 +662,8 @@ static int hdev_open(BlockDriverState *b
         open_flags |= O_RDONLY;
         bs->read_only = 1;
     }
+    if (flags & BDRV_O_DIRECT)
+        open_flags |= O_DIRECT;
 
     s->type = FTYPE_FILE;
 #if defined(__linux__)
Index: qemu/block.h
===================================================================
--- qemu.orig/block.h   2007-11-25 18:10:07.000000000 +0100
+++ qemu/block.h        2007-11-25 18:21:04.000000000 +0100
@@ -44,6 +44,7 @@ typedef struct QEMUSnapshotInfo {
                                      use a disk image format on top of
                                      it (default for
                                      bdrv_file_open()) */
+#define BDRV_O_DIRECT      0x0020
 
 #ifndef QEMU_IMG
 void bdrv_info(void);
Index: qemu/vl.c
===================================================================
--- qemu.orig/vl.c      2007-11-25 18:10:07.000000000 +0100
+++ qemu/vl.c   2007-11-25 18:21:04.000000000 +0100
@@ -4847,8 +4847,11 @@ static int drive_init(const char *str, i
     BlockDriverState *bdrv;
     int max_devs;
     int index;
+    int directio;
+    int bdrv_flags;
     char *params[] = { "bus", "unit", "if", "index", "cyls", "heads",
-                       "secs", "trans", "media", "snapshot", "file", NULL };
+                       "secs", "trans", "media", "snapshot", "file",
+                       "directio", NULL };
 
     if (check_params(buf, sizeof(buf), params, str) < 0) {
          fprintf(stderr, "qemu: unknowm parameter '%s' in '%s'\n",
@@ -4862,6 +4865,7 @@ static int drive_init(const char *str, i
     unit_id = -1;
     translation = BIOS_ATA_TRANSLATION_AUTO;
     index = -1;
+    directio = 0;
 
     if (!strcmp(machine->name, "realview") ||
         !strcmp(machine->name, "SS-5") ||
@@ -5001,6 +5005,17 @@ static int drive_init(const char *str, i
        }
     }
 
+    if (get_param_value(buf, sizeof(buf), "directio", str)) {
+        if (!strcmp(buf, "off"))
+            directio = 0;
+        else if (!strcmp(buf, "on"))
+            directio = 1;
+        else {
+           fprintf(stderr, "qemu: invalid directio option\n");
+           return -1;
+        }
+    }
+
     get_param_value(file, sizeof(file), "file", str);
 
     /* compute bus and unit according index */
@@ -5088,8 +5103,12 @@ static int drive_init(const char *str, i
     }
     if (!file[0])
         return 0;
-    if (bdrv_open(bdrv, file, snapshot ? BDRV_O_SNAPSHOT : 0) < 0 ||
-        qemu_key_check(bdrv, file)) {
+    bdrv_flags = 0;
+    if (snapshot)
+        bdrv_flags |= BDRV_O_SNAPSHOT;
+    if (directio)
+        bdrv_flags |= BDRV_O_DIRECT;
+    if (bdrv_open(bdrv, file, bdrv_flags) < 0 || qemu_key_check(bdrv, file)) {
         fprintf(stderr, "qemu: could not open disk image %s\n",
                         file);
         return -1;
@@ -7434,6 +7453,7 @@ static void help(int exitcode)
            "-cdrom file     use 'file' as IDE cdrom image (cdrom is ide1 
master)\n"
           "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][index=i]\n"
            "       [,cyls=c,heads=h,secs=s[,trans=t]][snapshot=on|off]\n"
+           "       [directio=on|off]\n"
           "                use 'file' as a drive image\n"
            "-mtdblock file  use 'file' as on-board Flash memory image\n"
            "-sd file        use 'file' as SecureDigital card image\n"
Index: qemu/hw/ide.c
===================================================================
--- qemu.orig/hw/ide.c  2007-11-25 18:10:07.000000000 +0100
+++ qemu/hw/ide.c       2007-11-25 18:21:04.000000000 +0100
@@ -365,7 +365,7 @@ typedef struct IDEState {
     EndTransferFunc *end_transfer_func;
     uint8_t *data_ptr;
     uint8_t *data_end;
-    uint8_t io_buffer[MAX_MULT_SECTORS*512 + 4];
+    uint8_t *io_buffer;
     QEMUTimer *sector_write_timer; /* only used for win2k install hack */
     uint32_t irq_count; /* counts IRQs when using win2k install hack */
     /* CF-ATA extended error */
@@ -2372,11 +2372,14 @@ struct partition {
 static int guess_disk_lchs(IDEState *s,
                            int *pcylinders, int *pheads, int *psectors)
 {
-    uint8_t buf[512];
+    uint8_t *buf;
     int ret, i, heads, sectors, cylinders;
     struct partition *p;
     uint32_t nr_sects;
 
+    ret = posix_memalign((void**)&buf, 0x200, 512);
+    if (ret < 0)
+        return -1;
     ret = bdrv_read(s->bs, 0, buf, 1);
     if (ret < 0)
         return -1;
@@ -2420,6 +2423,7 @@ static void ide_init2(IDEState *ide_stat
 
     for(i = 0; i < 2; i++) {
         s = ide_state + i;
+        posix_memalign((void**)&s->io_buffer, 0x200, MAX_MULT_SECTORS*512 + 4);
         if (i == 0)
             s->bs = hd0;
         else
Index: qemu/block.c
===================================================================
--- qemu.orig/block.c   2007-11-25 18:10:07.000000000 +0100
+++ qemu/block.c        2007-11-25 18:21:04.000000000 +0100
@@ -380,7 +380,7 @@ int bdrv_open2(BlockDriverState *bs, con
     /* Note: for compatibility, we open disk image files as RDWR, and
        RDONLY as fallback */
     if (!(flags & BDRV_O_FILE))
-        open_flags = BDRV_O_RDWR;
+        open_flags = BDRV_O_RDWR | (flags & BDRV_O_DIRECT);
     else
         open_flags = flags & ~(BDRV_O_FILE | BDRV_O_SNAPSHOT);
     ret = drv->bdrv_open(bs, filename, open_flags);
Index: qemu/hw/scsi-disk.c
===================================================================
--- qemu.orig/hw/scsi-disk.c    2007-11-25 18:10:07.000000000 +0100
+++ qemu/hw/scsi-disk.c 2007-11-25 18:21:04.000000000 +0100
@@ -46,7 +46,7 @@ typedef struct SCSIRequest {
     int sector_count;
     /* The amounnt of data in the buffer.  */
     int buf_len;
-    uint8_t dma_buf[SCSI_DMA_BUF_SIZE];
+    uint8_t *dma_buf;
     BlockDriverAIOCB *aiocb;
     struct SCSIRequest *next;
 } SCSIRequest;
@@ -78,6 +78,7 @@ static SCSIRequest *scsi_new_request(SCS
         free_requests = r->next;
     } else {
         r = qemu_malloc(sizeof(SCSIRequest));
+        posix_memalign(&r->dma_buf, 0x200, SCSI_DMA_BUF_SIZE);
     }
     r->dev = s;
     r->tag = tag;
Index: qemu/hw/sd.c
===================================================================
--- qemu.orig/hw/sd.c   2007-11-25 18:10:07.000000000 +0100
+++ qemu/hw/sd.c        2007-11-25 18:21:04.000000000 +0100
@@ -1284,10 +1284,16 @@ int sd_do_command(SDState *sd, struct sd
 static void sd_blk_read(BlockDriverState *bdrv,
                 void *data, uint32_t addr, uint32_t len)
 {
-    uint8_t buf[512];
+    uint8_t *buf;
     uint32_t end = addr + len;
 
+    if (posix_memalign(&buf, 512, 512) < 0) {
+        printf("sd_blk_read: cannot allocate memory\n");
+        return;
+    }
+
     if (!bdrv || bdrv_read(bdrv, addr >> 9, buf, 1) == -1) {
+        free(buf);
         printf("sd_blk_read: read error on host side\n");
         return;
     }
@@ -1297,11 +1303,13 @@ static void sd_blk_read(BlockDriverState
 
         if (bdrv_read(bdrv, end >> 9, buf, 1) == -1) {
             printf("sd_blk_read: read error on host side\n");
+            free(buf);
             return;
         }
         memcpy(data + 512 - (addr & 511), buf, end & 511);
     } else
         memcpy(data, buf + (addr & 511), len);
+    free(buf);
 }
 
 static void sd_blk_write(BlockDriverState *bdrv,
Index: qemu/hw/fdc.c
===================================================================
--- qemu.orig/hw/fdc.c  2007-11-25 18:10:07.000000000 +0100
+++ qemu/hw/fdc.c       2007-11-25 18:21:04.000000000 +0100
@@ -382,7 +382,7 @@ struct fdctrl_t {
     uint8_t cur_drv;
     uint8_t bootsel;
     /* Command FIFO */
-    uint8_t fifo[FD_SECTOR_LEN];
+    uint8_t *fifo;
     uint32_t data_pos;
     uint32_t data_len;
     uint8_t data_state;
@@ -598,6 +598,10 @@ fdctrl_t *fdctrl_init (qemu_irq irq, int
     fdctrl = qemu_mallocz(sizeof(fdctrl_t));
     if (!fdctrl)
         return NULL;
+    if (posix_memalign((void**)&fdctrl->fifo, 512, FD_SECTOR_LEN) <0) {
+        free(fdctrl);
+        return NULL;
+    }
     fdctrl->result_timer = qemu_new_timer(vm_clock,
                                           fdctrl_result_timer, fdctrl);