mirror of https://gitee.com/openkylin/qemu.git
scsi-disk: add scsi-block for device passthrough
scsi-block is a new device that supports device passthrough of Linux block devices (i.e. /dev/sda, not /dev/sg0). It uses SG_IO for commands other than I/O commands, and regular AIO read/writes for I/O commands. Besides being simpler to configure (no mapping required to scsi-generic device names), this removes the need for a large bounce buffer and, in the future, will get scatter/gather support for free from scsi-disk. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Paolo Bonzini
Kevin Wolf
parent
71544d30a6
commit
336a6915bc
118
hw/scsi-disk.c
118
hw/scsi-disk.c
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@ -39,6 +39,10 @@ do { fprintf(stderr, "scsi-disk: " fmt , ## __VA_ARGS__); } while (0)
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#include "blockdev.h"
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#include "block_int.h"
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#ifdef __linux
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#include <scsi/sg.h>
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#endif
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#define SCSI_DMA_BUF_SIZE 131072
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#define SCSI_MAX_INQUIRY_LEN 256
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@ -1588,6 +1592,105 @@ static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun,
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return req;
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}
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#ifdef __linux__
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static int get_device_type(SCSIDiskState *s)
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{
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BlockDriverState *bdrv = s->qdev.conf.bs;
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uint8_t cmd[16];
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uint8_t buf[36];
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uint8_t sensebuf[8];
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sg_io_hdr_t io_header;
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int ret;
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memset(cmd, 0, sizeof(cmd));
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memset(buf, 0, sizeof(buf));
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cmd[0] = INQUIRY;
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cmd[4] = sizeof(buf);
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memset(&io_header, 0, sizeof(io_header));
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io_header.interface_id = 'S';
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io_header.dxfer_direction = SG_DXFER_FROM_DEV;
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io_header.dxfer_len = sizeof(buf);
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io_header.dxferp = buf;
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io_header.cmdp = cmd;
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io_header.cmd_len = sizeof(cmd);
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io_header.mx_sb_len = sizeof(sensebuf);
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io_header.sbp = sensebuf;
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io_header.timeout = 6000; /* XXX */
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ret = bdrv_ioctl(bdrv, SG_IO, &io_header);
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if (ret < 0 || io_header.driver_status || io_header.host_status) {
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return -1;
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}
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s->qdev.type = buf[0];
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s->removable = (buf[1] & 0x80) != 0;
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return 0;
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}
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static int scsi_block_initfn(SCSIDevice *dev)
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{
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SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, dev);
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int sg_version;
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int rc;
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if (!s->qdev.conf.bs) {
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error_report("scsi-block: drive property not set");
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return -1;
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}
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/* check we are using a driver managing SG_IO (version 3 and after) */
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if (bdrv_ioctl(s->qdev.conf.bs, SG_GET_VERSION_NUM, &sg_version) < 0 ||
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sg_version < 30000) {
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error_report("scsi-block: scsi generic interface too old");
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return -1;
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}
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/* get device type from INQUIRY data */
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rc = get_device_type(s);
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if (rc < 0) {
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error_report("scsi-block: INQUIRY failed");
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return -1;
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}
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/* Make a guess for the block size, we'll fix it when the guest sends.
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* READ CAPACITY. If they don't, they likely would assume these sizes
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* anyway. (TODO: check in /sys).
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*/
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if (s->qdev.type == TYPE_ROM || s->qdev.type == TYPE_WORM) {
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s->qdev.blocksize = 2048;
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} else {
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s->qdev.blocksize = 512;
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}
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return scsi_initfn(&s->qdev);
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}
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static SCSIRequest *scsi_block_new_request(SCSIDevice *d, uint32_t tag,
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uint32_t lun, uint8_t *buf,
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void *hba_private)
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{
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SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
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switch (buf[0]) {
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case READ_6:
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case READ_10:
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case READ_12:
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case READ_16:
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case WRITE_6:
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case WRITE_10:
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case WRITE_12:
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case WRITE_16:
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case WRITE_VERIFY_10:
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case WRITE_VERIFY_12:
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case WRITE_VERIFY_16:
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return scsi_req_alloc(&scsi_disk_reqops, &s->qdev, tag, lun,
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hba_private);
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}
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return scsi_req_alloc(&scsi_generic_req_ops, &s->qdev, tag, lun,
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hba_private);
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}
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#endif
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#define DEFINE_SCSI_DISK_PROPERTIES() \
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DEFINE_BLOCK_PROPERTIES(SCSIDiskState, qdev.conf), \
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DEFINE_PROP_STRING("ver", SCSIDiskState, version), \
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@ -1623,6 +1726,21 @@ static SCSIDeviceInfo scsi_disk_info[] = {
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DEFINE_SCSI_DISK_PROPERTIES(),
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DEFINE_PROP_END_OF_LIST(),
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},
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#ifdef __linux__
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},{
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.qdev.name = "scsi-block",
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.qdev.fw_name = "disk",
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.qdev.desc = "SCSI block device passthrough",
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.qdev.size = sizeof(SCSIDiskState),
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.qdev.reset = scsi_disk_reset,
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.init = scsi_block_initfn,
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.destroy = scsi_destroy,
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.alloc_req = scsi_block_new_request,
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.qdev.props = (Property[]) {
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DEFINE_SCSI_DISK_PROPERTIES(),
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DEFINE_PROP_END_OF_LIST(),
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},
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#endif
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},{
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.qdev.name = "scsi-disk", /* legacy -device scsi-disk */
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.qdev.fw_name = "disk",
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