From b0e5d90ebc3edb5cfc1d5d33dd3334482dee6d46 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Mon, 26 Jan 2015 17:26:42 +0100 Subject: dataplane: endianness-aware accesses The vring.c code currently assumes that guest and host endianness match, which is not true for a number of cases: - emulating targets with a different endianness than the host - bi-endian targets, where the correct endianness depends on the virtio device - upcoming support for the virtio-1 standard mandates little-endian accesses even for big-endian targets and hosts Make sure to use accessors that depend on the virtio device. Note that dataplane now needs to be built per-target. Cc: Stefan Hajnoczi Cc: Paolo Bonzini Cc: Fam Zheng Reviewed-by: David Gibson Tested-by: David Gibson Signed-off-by: Cornelia Huck Reviewed-by: Stefan Hajnoczi Message-id: 1422289602-17874-2-git-send-email-cornelia.huck@de.ibm.com Signed-off-by: Stefan Hajnoczi --- hw/block/dataplane/virtio-blk.c | 4 ++- hw/scsi/virtio-scsi-dataplane.c | 2 +- hw/virtio/Makefile.objs | 2 +- hw/virtio/dataplane/Makefile.objs | 2 +- hw/virtio/dataplane/vring.c | 53 +++++++++++++++++++++++++-------------- 5 files changed, 40 insertions(+), 23 deletions(-) (limited to 'hw') diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index be957d1..cd41478 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -16,7 +16,9 @@ #include "qemu/iov.h" #include "qemu/thread.h" #include "qemu/error-report.h" +#include "hw/virtio/virtio-access.h" #include "hw/virtio/dataplane/vring.h" +#include "hw/virtio/dataplane/vring-accessors.h" #include "sysemu/block-backend.h" #include "hw/virtio/virtio-blk.h" #include "virtio-blk.h" @@ -75,7 +77,7 @@ static void complete_request_vring(VirtIOBlockReq *req, unsigned char status) VirtIOBlockDataPlane *s = req->dev->dataplane; stb_p(&req->in->status, status); - vring_push(&req->dev->dataplane->vring, &req->elem, + vring_push(s->vdev, &req->dev->dataplane->vring, &req->elem, req->qiov.size + sizeof(*req->in)); /* Suppress notification to guest by BH and its scheduled diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c index 03a1e8c..418d73b 100644 --- a/hw/scsi/virtio-scsi-dataplane.c +++ b/hw/scsi/virtio-scsi-dataplane.c @@ -94,7 +94,7 @@ void virtio_scsi_vring_push_notify(VirtIOSCSIReq *req) { VirtIODevice *vdev = VIRTIO_DEVICE(req->vring->parent); - vring_push(&req->vring->vring, &req->elem, + vring_push(vdev, &req->vring->vring, &req->elem, req->qsgl.size + req->resp_iov.size); if (vring_should_notify(vdev, &req->vring->vring)) { diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs index d21c397..19b224a 100644 --- a/hw/virtio/Makefile.objs +++ b/hw/virtio/Makefile.objs @@ -2,7 +2,7 @@ common-obj-y += virtio-rng.o common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o common-obj-y += virtio-bus.o common-obj-y += virtio-mmio.o -common-obj-$(CONFIG_VIRTIO) += dataplane/ +obj-$(CONFIG_VIRTIO) += dataplane/ obj-y += virtio.o virtio-balloon.o obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o vhost-user.o diff --git a/hw/virtio/dataplane/Makefile.objs b/hw/virtio/dataplane/Makefile.objs index 9a8cfc0..753a9ca 100644 --- a/hw/virtio/dataplane/Makefile.objs +++ b/hw/virtio/dataplane/Makefile.objs @@ -1 +1 @@ -common-obj-y += vring.o +obj-y += vring.o diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c index 78c6f45..0936f65 100644 --- a/hw/virtio/dataplane/vring.c +++ b/hw/virtio/dataplane/vring.c @@ -18,7 +18,9 @@ #include "hw/hw.h" #include "exec/memory.h" #include "exec/address-spaces.h" +#include "hw/virtio/virtio-access.h" #include "hw/virtio/dataplane/vring.h" +#include "hw/virtio/dataplane/vring-accessors.h" #include "qemu/error-report.h" /* vring_map can be coupled with vring_unmap or (if you still have the @@ -83,7 +85,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n) vring_init(&vring->vr, virtio_queue_get_num(vdev, n), vring_ptr, 4096); vring->last_avail_idx = virtio_queue_get_last_avail_idx(vdev, n); - vring->last_used_idx = vring->vr.used->idx; + vring->last_used_idx = vring_get_used_idx(vdev, vring); vring->signalled_used = 0; vring->signalled_used_valid = false; @@ -104,7 +106,7 @@ void vring_teardown(Vring *vring, VirtIODevice *vdev, int n) void vring_disable_notification(VirtIODevice *vdev, Vring *vring) { if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) { - vring->vr.used->flags |= VRING_USED_F_NO_NOTIFY; + vring_set_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY); } } @@ -117,10 +119,10 @@ bool vring_enable_notification(VirtIODevice *vdev, Vring *vring) if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) { vring_avail_event(&vring->vr) = vring->vr.avail->idx; } else { - vring->vr.used->flags &= ~VRING_USED_F_NO_NOTIFY; + vring_clear_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY); } smp_mb(); /* ensure update is seen before reading avail_idx */ - return !vring_more_avail(vring); + return !vring_more_avail(vdev, vring); } /* This is stolen from linux/drivers/vhost/vhost.c:vhost_notify() */ @@ -134,12 +136,13 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring) smp_mb(); if ((vdev->guest_features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) && - unlikely(vring->vr.avail->idx == vring->last_avail_idx)) { + unlikely(!vring_more_avail(vdev, vring))) { return true; } if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) { - return !(vring->vr.avail->flags & VRING_AVAIL_F_NO_INTERRUPT); + return !(vring_get_avail_flags(vdev, vring) & + VRING_AVAIL_F_NO_INTERRUPT); } old = vring->signalled_used; v = vring->signalled_used_valid; @@ -202,9 +205,19 @@ static int get_desc(Vring *vring, VirtQueueElement *elem, return 0; } +static void copy_in_vring_desc(VirtIODevice *vdev, + const struct vring_desc *guest, + struct vring_desc *host) +{ + host->addr = virtio_ldq_p(vdev, &guest->addr); + host->len = virtio_ldl_p(vdev, &guest->len); + host->flags = virtio_lduw_p(vdev, &guest->flags); + host->next = virtio_lduw_p(vdev, &guest->next); +} + /* This is stolen from linux/drivers/vhost/vhost.c. */ -static int get_indirect(Vring *vring, VirtQueueElement *elem, - struct vring_desc *indirect) +static int get_indirect(VirtIODevice *vdev, Vring *vring, + VirtQueueElement *elem, struct vring_desc *indirect) { struct vring_desc desc; unsigned int i = 0, count, found = 0; @@ -244,7 +257,7 @@ static int get_indirect(Vring *vring, VirtQueueElement *elem, vring->broken = true; return -EFAULT; } - desc = *desc_ptr; + copy_in_vring_desc(vdev, desc_ptr, &desc); memory_region_unref(mr); /* Ensure descriptor has been loaded before accessing fields */ @@ -320,7 +333,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring, /* Check it isn't doing very strange things with descriptor numbers. */ last_avail_idx = vring->last_avail_idx; - avail_idx = vring->vr.avail->idx; + avail_idx = vring_get_avail_idx(vdev, vring); barrier(); /* load indices now and not again later */ if (unlikely((uint16_t)(avail_idx - last_avail_idx) > num)) { @@ -341,7 +354,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring, /* Grab the next descriptor number they're advertising, and increment * the index we've seen. */ - head = vring->vr.avail->ring[last_avail_idx % num]; + head = vring_get_avail_ring(vdev, vring, last_avail_idx % num); elem->index = head; @@ -365,13 +378,13 @@ int vring_pop(VirtIODevice *vdev, Vring *vring, ret = -EFAULT; goto out; } - desc = vring->vr.desc[i]; + copy_in_vring_desc(vdev, &vring->vr.desc[i], &desc); /* Ensure descriptor is loaded before accessing fields */ barrier(); if (desc.flags & VRING_DESC_F_INDIRECT) { - ret = get_indirect(vring, elem, &desc); + ret = get_indirect(vdev, vring, elem, &desc); if (ret < 0) { goto out; } @@ -407,9 +420,9 @@ out: * * Stolen from linux/drivers/vhost/vhost.c. */ -void vring_push(Vring *vring, VirtQueueElement *elem, int len) +void vring_push(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem, + int len) { - struct vring_used_elem *used; unsigned int head = elem->index; uint16_t new; @@ -422,14 +435,16 @@ void vring_push(Vring *vring, VirtQueueElement *elem, int len) /* The virtqueue contains a ring of used buffers. Get a pointer to the * next entry in that used ring. */ - used = &vring->vr.used->ring[vring->last_used_idx % vring->vr.num]; - used->id = head; - used->len = len; + vring_set_used_ring_id(vdev, vring, vring->last_used_idx % vring->vr.num, + head); + vring_set_used_ring_len(vdev, vring, vring->last_used_idx % vring->vr.num, + len); /* Make sure buffer is written before we update index. */ smp_wmb(); - new = vring->vr.used->idx = ++vring->last_used_idx; + new = ++vring->last_used_idx; + vring_set_used_idx(vdev, vring, new); if (unlikely((int16_t)(new - vring->signalled_used) < (uint16_t)1)) { vring->signalled_used_valid = false; } -- cgit v1.1 From 9a925356e3a109c412240721890c1e6c1a86d286 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Thu, 5 Feb 2015 13:58:15 -0500 Subject: block/xen: Use blk_new_open() in blk_connect() As part of the required changes, this fixes a bug where specifying an invalid driver would result in the block layer probing the image format; now it will result in an error, unless "" is specified as the driver name. Fixing this would require further work on the xen_disk code which does not seem worth it (at this point and for this patch). Signed-off-by: Max Reitz Reviewed-by: Eric Blake Message-id: 1423162705-32065-7-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi --- hw/block/xen_disk.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-) (limited to 'hw') diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index 21842a0..267d8a8 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -40,6 +40,8 @@ #include "xen_blkif.h" #include "sysemu/blockdev.h" #include "sysemu/block-backend.h" +#include "qapi/qmp/qdict.h" +#include "qapi/qmp/qstring.h" /* ------------------------------------------------------------- */ @@ -897,30 +899,23 @@ static int blk_connect(struct XenDevice *xendev) blkdev->dinfo = drive_get(IF_XEN, 0, index); if (!blkdev->dinfo) { Error *local_err = NULL; - BlockBackend *blk; - BlockDriver *drv; - BlockDriverState *bs; + QDict *options = NULL; - /* setup via xenbus -> create new block driver instance */ - xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n"); - blk = blk_new_with_bs(blkdev->dev, NULL); - if (!blk) { - return -1; + if (strcmp(blkdev->fileproto, "")) { + options = qdict_new(); + qdict_put(options, "driver", qstring_from_str(blkdev->fileproto)); } - blkdev->blk = blk; - bs = blk_bs(blk); - drv = bdrv_find_whitelisted_format(blkdev->fileproto, readonly); - if (bdrv_open(&bs, blkdev->filename, NULL, NULL, qflags, - drv, &local_err) != 0) { + /* setup via xenbus -> create new block driver instance */ + xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n"); + blkdev->blk = blk_new_open(blkdev->dev, blkdev->filename, NULL, options, + qflags, &local_err); + if (!blkdev->blk) { xen_be_printf(&blkdev->xendev, 0, "error: %s\n", error_get_pretty(local_err)); error_free(local_err); - blk_unref(blk); - blkdev->blk = NULL; return -1; } - assert(bs == blk_bs(blk)); } else { /* setup via qemu cmdline -> already setup for us */ xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n"); -- cgit v1.1