[Libguestfs] [PATCH v2 5/9] appliance: Add support for virtio-scsi.

From: "Richard W.M. Jones" <rjones(a)redhat.com&gt; This requires febootstrap >= 3.15. --- README | 3 +- src/guestfs-internal.h | 3 ++ src/launch.c | 140 +++++++++++++++++++++++++++++++++++++++--------- 3 files changed, 121 insertions(+), 25 deletions(-) diff --git a/README b/README index 4dd2075..51ee4a0 100644 --- a/README +++ b/README @@ -55,11 +55,12 @@ For basic functionality and the C tools: to make complex changes to the ./configure command line to get it to work if you don't have virtio) -- febootstrap >= 3.3 (it is best to use the latest version) +- febootstrap >= 3.15 Notes: (1) febootstrap 2.x WILL NOT WORK (2) febootstrap 3.x is distro-independent, and is required on Debian and other distros as well as Fedora + (3) that is the minimum version, but later versions are better - XDR, rpcgen (on Linux these are provided by glibc) diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h index fb4868c..0cdc8f2 100644 --- a/src/guestfs-internal.h +++ b/src/guestfs-internal.h @@ -257,6 +257,9 @@ struct guestfs_h int ml_read_only; /* If mounted read-only. */ int ml_debug_calls; /* Extra debug info on each FUSE call. */ #endif + + /* Used by src/launch.c:qemu_supports_virtio_scsi */ + int virtio_scsi; }; /* Per-filesystem data stored for inspect_os. */ diff --git a/src/launch.c b/src/launch.c index 1eae027..b7a08ba 100644 --- a/src/launch.c +++ b/src/launch.c @@ -78,7 +78,10 @@ static int64_t timeval_diff (const struct timeval *x, const struct timeval *y); static void print_qemu_command_line (guestfs_h *g, char **argv); static int connect_unix_socket (guestfs_h *g, const char *sock); static int qemu_supports (guestfs_h *g, const char *option); -static char *qemu_drive_param (guestfs_h *g, const struct drive *drv); +static int qemu_supports_device (guestfs_h *g, const char *device_name); +static int qemu_supports_virtio_scsi (guestfs_h *g); +static char *qemu_drive_param (guestfs_h *g, const struct drive *drv, size_t index); +static char *drive_name (size_t index, char *ret); #if 0 static int qemu_supports_re (guestfs_h *g, const pcre *option_regex); @@ -248,7 +251,7 @@ guestfs__debug_drives (guestfs_h *g) ret = safe_malloc (g, sizeof (char *) * (count + 1)); for (i = 0, drv = g->drives; drv; i++, drv = drv->next) - ret[i] = qemu_drive_param (g, drv); + ret[i] = qemu_drive_param (g, drv, i); ret[count] = NULL; @@ -620,6 +623,7 @@ launch_appliance (guestfs_h *g) if (r == 0) { /* Child (qemu). */ char buf[256]; + int virtio_scsi = qemu_supports_virtio_scsi (g); /* Set up the full command line. Do this in the subprocess so we * don't need to worry about cleaning up. @@ -660,15 +664,59 @@ launch_appliance (guestfs_h *g) /* Add drives */ struct drive *drv = g->drives; + size_t drv_index = 0; + + if (virtio_scsi) { + /* Create the virtio-scsi bus. */ + add_cmdline (g, "-device"); + add_cmdline (g, "virtio-scsi-pci,id=scsi"); + } + while (drv != NULL) { /* Construct the final -drive parameter. */ - char *buf = qemu_drive_param (g, drv); + char *buf = qemu_drive_param (g, drv, drv_index); add_cmdline (g, "-drive"); add_cmdline (g, buf); free (buf); + if (virtio_scsi && drv->iface == NULL) { + char buf2[64]; + snprintf (buf2, sizeof buf2, "scsi-hd,drive=hd%zu", drv_index); + add_cmdline (g, "-device"); + add_cmdline (g, buf2); + } + drv = drv->next; + drv_index++; + } + + char appliance_root[64] = ""; + + /* Add the ext2 appliance drive (after all the drives). */ + if (appliance) { + const char *cachemode = ""; + if (qemu_supports (g, "cache=")) { + if (qemu_supports (g, "unsafe")) + cachemode = ",cache=unsafe"; + else if (qemu_supports (g, "writeback")) + cachemode = ",cache=writeback"; + } + + char buf2[PATH_MAX + 64]; + add_cmdline (g, "-drive"); + snprintf (buf2, sizeof buf2, "file=%s,snapshot=on,id=appliance,if=%s%s", + appliance, virtio_scsi ? "none" : "virtio", cachemode); + add_cmdline (g, buf2); + + if (virtio_scsi) { + add_cmdline (g, "-device"); + add_cmdline (g, "scsi-hd,drive=appliance"); + } + + snprintf (appliance_root, sizeof appliance_root, "root=/dev/%cd", + virtio_scsi ? 's' : 'v'); + drive_name (drv_index, &appliance_root[12]); } if (STRNEQ (QEMU_OPTIONS, "")) { @@ -792,10 +840,12 @@ launch_appliance (guestfs_h *g) /* Linux kernel command line. */ snprintf (buf, sizeof buf, LINUX_CMDLINE + "%s " /* (root) */ "%s " /* (selinux) */ "%s " /* (verbose) */ "TERM=%s " /* (TERM environment variable) */ "%s", /* (append) */ + appliance_root, g->selinux ? "selinux=1 enforcing=0" : "selinux=0", g->verbose ? "guestfs_verbose=1" : "", getenv ("TERM") ? : "linux", @@ -808,23 +858,6 @@ launch_appliance (guestfs_h *g) add_cmdline (g, "-append"); add_cmdline (g, buf); - /* Add the ext2 appliance drive (last of all). */ - if (appliance) { - const char *cachemode = ""; - if (qemu_supports (g, "cache=")) { - if (qemu_supports (g, "unsafe")) - cachemode = ",cache=unsafe"; - else if (qemu_supports (g, "writeback")) - cachemode = ",cache=writeback"; - } - - char buf2[PATH_MAX + 64]; - add_cmdline (g, "-drive"); - snprintf (buf2, sizeof buf2, "file=%s,snapshot=on,if=virtio%s", - appliance, cachemode); - add_cmdline (g, buf2); - } - /* Finish off the command line. */ incr_cmdline_size (g); g->cmdline[g->cmdline_size-1] = NULL; @@ -1432,6 +1465,20 @@ qemu_supports_re (guestfs_h *g, const pcre *option_regex) } #endif +/* Test if device is supported by qemu (currently just greps the -device ? + * output). + */ +static int +qemu_supports_device (guestfs_h *g, const char *device_name) +{ + if (!g->qemu_devices) { + if (test_qemu (g) == -1) + return -1; + } + + return strstr (g->qemu_devices, device_name) != NULL; +} + #if defined(__i386__) || defined(__x86_64__) /* Check if a file can be opened. */ static int @@ -1447,13 +1494,39 @@ is_openable (guestfs_h *g, const char *path, int flags) } #endif +/* Returns 1 = use virtio-scsi, or 0 = use virtio-blk. */ +static int +qemu_supports_virtio_scsi (guestfs_h *g) +{ + int r; + + /* g->virtio_scsi has these values: + * 0 = untested (after handle creation) + * 1 = supported + * 2 = not supported (use virtio-blk) + * 3 = test failed (use virtio-blk) + */ + if (g->virtio_scsi == 0) { + r = qemu_supports_device (g, "virtio-scsi-pci"); + if (r > 0) + g->virtio_scsi = 1; + else if (r == 0) + g->virtio_scsi = 2; + else + g->virtio_scsi = 3; + } + + return g->virtio_scsi == 1; +} + static char * -qemu_drive_param (guestfs_h *g, const struct drive *drv) +qemu_drive_param (guestfs_h *g, const struct drive *drv, size_t index) { size_t i; - size_t len = 64; + size_t len = 128; const char *p; char *r; + const char *iface; len += strlen (drv->path) * 2; /* every "," could become ",," */ if (drv->iface) @@ -1475,16 +1548,35 @@ qemu_drive_param (guestfs_h *g, const struct drive *drv) r[i++] = *p; } - snprintf (&r[i], len-i, "%s%s%s%s,if=%s", + if (drv->iface) + iface = drv->iface; + else if (qemu_supports_virtio_scsi (g)) + iface = "none"; /* sic */ + else + iface = "virtio"; + + snprintf (&r[i], len-i, "%s%s%s%s,id=hd%zu,if=%s", drv->readonly ? ",snapshot=on" : "", drv->use_cache_off ? ",cache=off" : "", drv->format ? ",format=" : "", drv->format ? drv->format : "", - drv->iface ? drv->iface : "virtio"); + index, + iface); return r; /* caller frees */ } +/* https://rwmj.wordpress.com/2011/01/09/how-are-linux-drives-named-beyond-d... */ +static char * +drive_name (size_t index, char *ret) +{ + if (index > 26) + ret = drive_name (index / 26, ret); + index %= 26; + *ret++ = 'a' + index; + return ret; +} + /* You had to call this function after launch in versions <= 1.0.70, * but it is now a no-op. */ -- 1.7.10.1