diff options
Diffstat (limited to 'tools/lguest/lguest.c')
| -rw-r--r-- | tools/lguest/lguest.c | 123 |
1 files changed, 65 insertions, 58 deletions
diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c index f759f4f097c..32cf2ce15d6 100644 --- a/tools/lguest/lguest.c +++ b/tools/lguest/lguest.c @@ -42,14 +42,10 @@ #include <pwd.h> #include <grp.h> -#include <linux/virtio_config.h> -#include <linux/virtio_net.h> -#include <linux/virtio_blk.h> -#include <linux/virtio_console.h> -#include <linux/virtio_rng.h> -#include <linux/virtio_ring.h> -#include <asm/bootparam.h> -#include "../../include/linux/lguest_launcher.h" +#ifndef VIRTIO_F_ANY_LAYOUT +#define VIRTIO_F_ANY_LAYOUT 27 +#endif + /*L:110 * We can ignore the 43 include files we need for this program, but I do want * to draw attention to the use of kernel-style types. @@ -65,6 +61,15 @@ typedef uint16_t u16; typedef uint8_t u8; /*:*/ +#include <linux/virtio_config.h> +#include <linux/virtio_net.h> +#include <linux/virtio_blk.h> +#include <linux/virtio_console.h> +#include <linux/virtio_rng.h> +#include <linux/virtio_ring.h> +#include <asm/bootparam.h> +#include "../../include/linux/lguest_launcher.h" + #define BRIDGE_PFX "bridge:" #ifndef SIOCBRADDIF #define SIOCBRADDIF 0x89a2 /* add interface to bridge */ @@ -177,30 +182,8 @@ static struct termios orig_term; * in precise order. */ #define wmb() __asm__ __volatile__("" : : : "memory") -#define mb() __asm__ __volatile__("" : : : "memory") - -/* - * Convert an iovec element to the given type. - * - * This is a fairly ugly trick: we need to know the size of the type and - * alignment requirement to check the pointer is kosher. It's also nice to - * have the name of the type in case we report failure. - * - * Typing those three things all the time is cumbersome and error prone, so we - * have a macro which sets them all up and passes to the real function. - */ -#define convert(iov, type) \ - ((type *)_convert((iov), sizeof(type), __alignof__(type), #type)) - -static void *_convert(struct iovec *iov, size_t size, size_t align, - const char *name) -{ - if (iov->iov_len != size) - errx(1, "Bad iovec size %zu for %s", iov->iov_len, name); - if ((unsigned long)iov->iov_base % align != 0) - errx(1, "Bad alignment %p for %s", iov->iov_base, name); - return iov->iov_base; -} +#define rmb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory") +#define mb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory") /* Wrapper for the last available index. Makes it easier to change. */ #define lg_last_avail(vq) ((vq)->last_avail_idx) @@ -228,7 +211,8 @@ static bool iov_empty(const struct iovec iov[], unsigned int num_iov) } /* Take len bytes from the front of this iovec. */ -static void iov_consume(struct iovec iov[], unsigned num_iov, unsigned len) +static void iov_consume(struct iovec iov[], unsigned num_iov, + void *dest, unsigned len) { unsigned int i; @@ -236,11 +220,16 @@ static void iov_consume(struct iovec iov[], unsigned num_iov, unsigned len) unsigned int used; used = iov[i].iov_len < len ? iov[i].iov_len : len; + if (dest) { + memcpy(dest, iov[i].iov_base, used); + dest += used; + } iov[i].iov_base += used; iov[i].iov_len -= used; len -= used; } - assert(len == 0); + if (len != 0) + errx(1, "iovec too short!"); } /* The device virtqueue descriptors are followed by feature bitmasks. */ @@ -693,6 +682,12 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq, errx(1, "Guest moved used index from %u to %u", last_avail, vq->vring.avail->idx); + /* + * Make sure we read the descriptor number *after* we read the ring + * update; don't let the cpu or compiler change the order. + */ + rmb(); + /* * Grab the next descriptor number they're advertising, and increment * the index we've seen. @@ -712,6 +707,12 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq, i = head; /* + * We have to read the descriptor after we read the descriptor number, + * but there's a data dependency there so the CPU shouldn't reorder + * that: no rmb() required. + */ + + /* * If this is an indirect entry, then this buffer contains a descriptor * table which we handle as if it's any normal descriptor chain. */ @@ -864,7 +865,7 @@ static void console_output(struct virtqueue *vq) warn("Write to stdout gave %i (%d)", len, errno); break; } - iov_consume(iov, out, len); + iov_consume(iov, out, NULL, len); } /* @@ -1299,6 +1300,7 @@ static struct device *new_device(const char *name, u16 type) dev->feature_len = 0; dev->num_vq = 0; dev->running = false; + dev->next = NULL; /* * Append to device list. Prepending to a single-linked list is @@ -1546,6 +1548,8 @@ static void setup_tun_net(char *arg) add_feature(dev, VIRTIO_NET_F_HOST_ECN); /* We handle indirect ring entries */ add_feature(dev, VIRTIO_RING_F_INDIRECT_DESC); + /* We're compliant with the damn spec. */ + add_feature(dev, VIRTIO_F_ANY_LAYOUT); set_config(dev, sizeof(conf), &conf); /* We don't need the socket any more; setup is done. */ @@ -1590,9 +1594,9 @@ static void blk_request(struct virtqueue *vq) { struct vblk_info *vblk = vq->dev->priv; unsigned int head, out_num, in_num, wlen; - int ret; + int ret, i; u8 *in; - struct virtio_blk_outhdr *out; + struct virtio_blk_outhdr out; struct iovec iov[vq->vring.num]; off64_t off; @@ -1602,32 +1606,36 @@ static void blk_request(struct virtqueue *vq) */ head = wait_for_vq_desc(vq, iov, &out_num, &in_num); - /* - * Every block request should contain at least one output buffer - * (detailing the location on disk and the type of request) and one - * input buffer (to hold the result). - */ - if (out_num == 0 || in_num == 0) - errx(1, "Bad virtblk cmd %u out=%u in=%u", - head, out_num, in_num); + /* Copy the output header from the front of the iov (adjusts iov) */ + iov_consume(iov, out_num, &out, sizeof(out)); + + /* Find and trim end of iov input array, for our status byte. */ + in = NULL; + for (i = out_num + in_num - 1; i >= out_num; i--) { + if (iov[i].iov_len > 0) { + in = iov[i].iov_base + iov[i].iov_len - 1; + iov[i].iov_len--; + break; + } + } + if (!in) + errx(1, "Bad virtblk cmd with no room for status"); - out = convert(&iov[0], struct virtio_blk_outhdr); - in = convert(&iov[out_num+in_num-1], u8); /* * For historical reasons, block operations are expressed in 512 byte * "sectors". */ - off = out->sector * 512; + off = out.sector * 512; /* * In general the virtio block driver is allowed to try SCSI commands. * It'd be nice if we supported eject, for example, but we don't. */ - if (out->type & VIRTIO_BLK_T_SCSI_CMD) { + if (out.type & VIRTIO_BLK_T_SCSI_CMD) { fprintf(stderr, "Scsi commands unsupported\n"); *in = VIRTIO_BLK_S_UNSUPP; wlen = sizeof(*in); - } else if (out->type & VIRTIO_BLK_T_OUT) { + } else if (out.type & VIRTIO_BLK_T_OUT) { /* * Write * @@ -1635,10 +1643,10 @@ static void blk_request(struct virtqueue *vq) * if they try to write past end. */ if (lseek64(vblk->fd, off, SEEK_SET) != off) - err(1, "Bad seek to sector %llu", out->sector); + err(1, "Bad seek to sector %llu", out.sector); - ret = writev(vblk->fd, iov+1, out_num-1); - verbose("WRITE to sector %llu: %i\n", out->sector, ret); + ret = writev(vblk->fd, iov, out_num); + verbose("WRITE to sector %llu: %i\n", out.sector, ret); /* * Grr... Now we know how long the descriptor they sent was, we @@ -1654,7 +1662,7 @@ static void blk_request(struct virtqueue *vq) wlen = sizeof(*in); *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); - } else if (out->type & VIRTIO_BLK_T_FLUSH) { + } else if (out.type & VIRTIO_BLK_T_FLUSH) { /* Flush */ ret = fdatasync(vblk->fd); verbose("FLUSH fdatasync: %i\n", ret); @@ -1668,10 +1676,9 @@ static void blk_request(struct virtqueue *vq) * if they try to read past end. */ if (lseek64(vblk->fd, off, SEEK_SET) != off) - err(1, "Bad seek to sector %llu", out->sector); + err(1, "Bad seek to sector %llu", out.sector); - ret = readv(vblk->fd, iov+1, in_num-1); - verbose("READ from sector %llu: %i\n", out->sector, ret); + ret = readv(vblk->fd, iov + out_num, in_num); if (ret >= 0) { wlen = sizeof(*in) + ret; *in = VIRTIO_BLK_S_OK; @@ -1757,7 +1764,7 @@ static void rng_input(struct virtqueue *vq) len = readv(rng_info->rfd, iov, in_num); if (len <= 0) err(1, "Read from /dev/random gave %i", len); - iov_consume(iov, in_num, len); + iov_consume(iov, in_num, NULL, len); totlen += len; } |