Since virtio existed even before it got standardized, the virtio standard defines the following types of virtio devices:
+ legacy device (pre-virtio 1.0) + non-legacy or VIRTIO 1.0 device + transitional device (which can act both as legacy and non-legacy) Virtio 1.0 defines the fields of the virtqueues as little endian, while legacy uses guest's native endian [1]. Currently libvhost-user does not handle virtio endianness at all, i.e. it works only if the native endianness matches with whatever is actually needed. That means things break spectacularly on big-endian targets. Let us handle virtio endianness for non-legacy as required by the virtio specification [1]. We will fence non-legacy virtio devices with the upcoming patch. [1] https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-210003 Signed-off-by: Marc Hartmayer <mhart...@linux.ibm.com> --- Note: As we don't support legacy virtio devices there is dead code in libvhost-access.h that could be removed. But for the sake of completeness, I left it in the code. --- contrib/libvhost-user/libvhost-access.h | 61 ++++++++++++ contrib/libvhost-user/libvhost-user.c | 119 ++++++++++++------------ 2 files changed, 121 insertions(+), 59 deletions(-) create mode 100644 contrib/libvhost-user/libvhost-access.h diff --git a/contrib/libvhost-user/libvhost-access.h b/contrib/libvhost-user/libvhost-access.h new file mode 100644 index 000000000000..868ba3e7bfb8 --- /dev/null +++ b/contrib/libvhost-user/libvhost-access.h @@ -0,0 +1,61 @@ +#ifndef LIBVHOST_ACCESS_H + +#include "qemu/bswap.h" + +#include "libvhost-user.h" + +static inline bool vu_access_is_big_endian(VuDev *dev) +{ + /* Devices conforming to VIRTIO 1.0 or later are always LE. */ + return false; +} + +static inline void vu_stw_p(VuDev *vdev, void *ptr, uint16_t v) +{ + if (vu_access_is_big_endian(vdev)) { + stw_be_p(ptr, v); + } else { + stw_le_p(ptr, v); + } +} + +static inline void vu_stl_p(VuDev *vdev, void *ptr, uint32_t v) +{ + if (vu_access_is_big_endian(vdev)) { + stl_be_p(ptr, v); + } else { + stl_le_p(ptr, v); + } +} + +static inline void vu_stq_p(VuDev *vdev, void *ptr, uint64_t v) +{ + if (vu_access_is_big_endian(vdev)) { + stq_be_p(ptr, v); + } else { + stq_le_p(ptr, v); + } +} + +static inline int vu_lduw_p(VuDev *vdev, const void *ptr) +{ + if (vu_access_is_big_endian(vdev)) + return lduw_be_p(ptr); + return lduw_le_p(ptr); +} + +static inline int vu_ldl_p(VuDev *vdev, const void *ptr) +{ + if (vu_access_is_big_endian(vdev)) + return ldl_be_p(ptr); + return ldl_le_p(ptr); +} + +static inline uint64_t vu_ldq_p(VuDev *vdev, const void *ptr) +{ + if (vu_access_is_big_endian(vdev)) + return ldq_be_p(ptr); + return ldq_le_p(ptr); +} + +#endif /* LIBVHOST_ACCESS_H */ diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c index d315db139606..0214b04c5291 100644 --- a/contrib/libvhost-user/libvhost-user.c +++ b/contrib/libvhost-user/libvhost-user.c @@ -45,6 +45,7 @@ #include "qemu/memfd.h" #include "libvhost-user.h" +#include "libvhost-access.h" /* usually provided by GLib */ #ifndef MIN @@ -1074,7 +1075,7 @@ vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vmsg) return false; } - vq->used_idx = vq->vring.used->idx; + vq->used_idx = vu_lduw_p(dev, &vq->vring.used->idx); if (vq->last_avail_idx != vq->used_idx) { bool resume = dev->iface->queue_is_processed_in_order && @@ -1191,7 +1192,7 @@ vu_check_queue_inflights(VuDev *dev, VuVirtq *vq) return 0; } - vq->used_idx = vq->vring.used->idx; + vq->used_idx = vu_lduw_p(dev, &vq->vring.used->idx); vq->resubmit_num = 0; vq->resubmit_list = NULL; vq->counter = 0; @@ -2019,35 +2020,35 @@ vu_queue_started(const VuDev *dev, const VuVirtq *vq) } static inline uint16_t -vring_avail_flags(VuVirtq *vq) +vring_avail_flags(VuDev *dev, VuVirtq *vq) { - return vq->vring.avail->flags; + return vu_lduw_p(dev, &vq->vring.avail->flags); } static inline uint16_t -vring_avail_idx(VuVirtq *vq) +vring_avail_idx(VuDev *dev, VuVirtq *vq) { - vq->shadow_avail_idx = vq->vring.avail->idx; + vq->shadow_avail_idx = vu_lduw_p(dev, &vq->vring.avail->idx); return vq->shadow_avail_idx; } static inline uint16_t -vring_avail_ring(VuVirtq *vq, int i) +vring_avail_ring(VuDev *dev, VuVirtq *vq, int i) { - return vq->vring.avail->ring[i]; + return vu_lduw_p(dev, &vq->vring.avail->ring[i]); } static inline uint16_t -vring_get_used_event(VuVirtq *vq) +vring_get_used_event(VuDev *dev, VuVirtq *vq) { - return vring_avail_ring(vq, vq->vring.num); + return vring_avail_ring(dev, vq, vq->vring.num); } static int virtqueue_num_heads(VuDev *dev, VuVirtq *vq, unsigned int idx) { - uint16_t num_heads = vring_avail_idx(vq) - idx; + uint16_t num_heads = vring_avail_idx(dev, vq) - idx; /* Check it isn't doing very strange things with descriptor numbers. */ if (num_heads > vq->vring.num) { @@ -2070,7 +2071,7 @@ virtqueue_get_head(VuDev *dev, VuVirtq *vq, { /* Grab the next descriptor number they're advertising, and increment * the index we've seen. */ - *head = vring_avail_ring(vq, idx % vq->vring.num); + *head = vring_avail_ring(dev, vq, idx % vq->vring.num); /* If their number is silly, that's a fatal mistake. */ if (*head >= vq->vring.num) { @@ -2123,12 +2124,12 @@ virtqueue_read_next_desc(VuDev *dev, struct vring_desc *desc, int i, unsigned int max, unsigned int *next) { /* If this descriptor says it doesn't chain, we're done. */ - if (!(desc[i].flags & VRING_DESC_F_NEXT)) { + if (!(vu_lduw_p(dev, &desc[i].flags) & VRING_DESC_F_NEXT)) { return VIRTQUEUE_READ_DESC_DONE; } /* Check they're not leading us off end of descriptors. */ - *next = desc[i].next; + *next = vu_lduw_p(dev, &desc[i].next); /* Make sure compiler knows to grab that: we don't want it changing! */ smp_wmb(); @@ -2171,8 +2172,8 @@ vu_queue_get_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int *in_bytes, } desc = vq->vring.desc; - if (desc[i].flags & VRING_DESC_F_INDIRECT) { - if (desc[i].len % sizeof(struct vring_desc)) { + if (vu_lduw_p(dev, &desc[i].flags) & VRING_DESC_F_INDIRECT) { + if (vu_ldl_p(dev, &desc[i].len) % sizeof(struct vring_desc)) { vu_panic(dev, "Invalid size for indirect buffer table"); goto err; } @@ -2185,8 +2186,8 @@ vu_queue_get_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int *in_bytes, /* loop over the indirect descriptor table */ indirect = 1; - desc_addr = desc[i].addr; - desc_len = desc[i].len; + desc_addr = vu_ldq_p(dev, &desc[i].addr); + desc_len = vu_ldl_p(dev, &desc[i].len); max = desc_len / sizeof(struct vring_desc); read_len = desc_len; desc = vu_gpa_to_va(dev, &read_len, desc_addr); @@ -2213,10 +2214,10 @@ vu_queue_get_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int *in_bytes, goto err; } - if (desc[i].flags & VRING_DESC_F_WRITE) { - in_total += desc[i].len; + if (vu_lduw_p(dev, &desc[i].flags) & VRING_DESC_F_WRITE) { + in_total += vu_ldl_p(dev, &desc[i].len); } else { - out_total += desc[i].len; + out_total += vu_ldl_p(dev, &desc[i].len); } if (in_total >= max_in_bytes && out_total >= max_out_bytes) { goto done; @@ -2277,7 +2278,7 @@ vu_queue_empty(VuDev *dev, VuVirtq *vq) return false; } - return vring_avail_idx(vq) == vq->last_avail_idx; + return vring_avail_idx(dev, vq) == vq->last_avail_idx; } static bool @@ -2296,14 +2297,14 @@ vring_notify(VuDev *dev, VuVirtq *vq) } if (!vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { - return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT); + return !(vring_avail_flags(dev, vq) & VRING_AVAIL_F_NO_INTERRUPT); } v = vq->signalled_used_valid; vq->signalled_used_valid = true; old = vq->signalled_used; new = vq->signalled_used = vq->used_idx; - return !v || vring_need_event(vring_get_used_event(vq), new, old); + return !v || vring_need_event(vring_get_used_event(dev, vq), new, old); } static void _vu_queue_notify(VuDev *dev, VuVirtq *vq, bool sync) @@ -2361,33 +2362,33 @@ void vu_queue_notify_sync(VuDev *dev, VuVirtq *vq) } static inline void -vring_used_flags_set_bit(VuVirtq *vq, int mask) +vring_used_flags_set_bit(VuDev *dev, VuVirtq *vq, int mask) +{ + uint16_t *flags; + + flags = (uint16_t *)(char*)vq->vring.used + + offsetof(struct vring_used, flags); + vu_stw_p(dev, flags, vu_lduw_p(dev, flags) | mask); +} + +static inline void +vring_used_flags_unset_bit(VuDev *dev, VuVirtq *vq, int mask) { uint16_t *flags; flags = (uint16_t *)((char*)vq->vring.used + offsetof(struct vring_used, flags)); - *flags |= mask; + vu_stw_p(dev, flags, vu_lduw_p(dev, flags) & ~mask); } static inline void -vring_used_flags_unset_bit(VuVirtq *vq, int mask) -{ - uint16_t *flags; - - flags = (uint16_t *)((char*)vq->vring.used + - offsetof(struct vring_used, flags)); - *flags &= ~mask; -} - -static inline void -vring_set_avail_event(VuVirtq *vq, uint16_t val) +vring_set_avail_event(VuDev *dev, VuVirtq *vq, uint16_t val) { if (!vq->notification) { return; } - *((uint16_t *) &vq->vring.used->ring[vq->vring.num]) = val; + vu_stw_p(dev, &vq->vring.used->ring[vq->vring.num], val); } void @@ -2395,11 +2396,11 @@ vu_queue_set_notification(VuDev *dev, VuVirtq *vq, int enable) { vq->notification = enable; if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { - vring_set_avail_event(vq, vring_avail_idx(vq)); + vring_set_avail_event(dev, vq, vring_avail_idx(dev, vq)); } else if (enable) { - vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY); + vring_used_flags_unset_bit(dev, vq, VRING_USED_F_NO_NOTIFY); } else { - vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY); + vring_used_flags_set_bit(dev, vq, VRING_USED_F_NO_NOTIFY); } if (enable) { /* Expose avail event/used flags before caller checks the avail idx. */ @@ -2476,14 +2477,14 @@ vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned int idx, size_t sz) struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE]; int rc; - if (desc[i].flags & VRING_DESC_F_INDIRECT) { - if (desc[i].len % sizeof(struct vring_desc)) { + if (vu_lduw_p(dev, &desc[i].flags) & VRING_DESC_F_INDIRECT) { + if (vu_ldl_p(dev, &desc[i].len) % sizeof(struct vring_desc)) { vu_panic(dev, "Invalid size for indirect buffer table"); } /* loop over the indirect descriptor table */ - desc_addr = desc[i].addr; - desc_len = desc[i].len; + desc_addr = vu_ldq_p(dev, &desc[i].addr); + desc_len = vu_ldl_p(dev, &desc[i].len); max = desc_len / sizeof(struct vring_desc); read_len = desc_len; desc = vu_gpa_to_va(dev, &read_len, desc_addr); @@ -2505,10 +2506,10 @@ vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned int idx, size_t sz) /* Collect all the descriptors */ do { - if (desc[i].flags & VRING_DESC_F_WRITE) { + if (vu_lduw_p(dev, &desc[i].flags) & VRING_DESC_F_WRITE) { virtqueue_map_desc(dev, &in_num, iov + out_num, VIRTQUEUE_MAX_SIZE - out_num, true, - desc[i].addr, desc[i].len); + vu_ldq_p(dev, &desc[i].addr), vu_ldl_p(dev, &desc[i].len)); } else { if (in_num) { vu_panic(dev, "Incorrect order for descriptors"); @@ -2516,7 +2517,7 @@ vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned int idx, size_t sz) } virtqueue_map_desc(dev, &out_num, iov, VIRTQUEUE_MAX_SIZE, false, - desc[i].addr, desc[i].len); + vu_ldq_p(dev, &desc[i].addr), vu_ldl_p(dev, &desc[i].len)); } /* If we've got too many, that implies a descriptor loop. */ @@ -2642,7 +2643,7 @@ vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz) } if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { - vring_set_avail_event(vq, vq->last_avail_idx); + vring_set_avail_event(dev, vq, vq->last_avail_idx); } elem = vu_queue_map_desc(dev, vq, head, sz); @@ -2712,14 +2713,14 @@ vu_log_queue_fill(VuDev *dev, VuVirtq *vq, max = vq->vring.num; i = elem->index; - if (desc[i].flags & VRING_DESC_F_INDIRECT) { - if (desc[i].len % sizeof(struct vring_desc)) { + if (vu_lduw_p(dev, &desc[i].flags) & VRING_DESC_F_INDIRECT) { + if (vu_ldl_p(dev, &desc[i].len) % sizeof(struct vring_desc)) { vu_panic(dev, "Invalid size for indirect buffer table"); } /* loop over the indirect descriptor table */ - desc_addr = desc[i].addr; - desc_len = desc[i].len; + desc_addr = vu_ldq_p(dev, &desc[i].addr); + desc_len = vu_ldl_p(dev, &desc[i].len); max = desc_len / sizeof(struct vring_desc); read_len = desc_len; desc = vu_gpa_to_va(dev, &read_len, desc_addr); @@ -2745,9 +2746,9 @@ vu_log_queue_fill(VuDev *dev, VuVirtq *vq, return; } - if (desc[i].flags & VRING_DESC_F_WRITE) { - min = MIN(desc[i].len, len); - vu_log_write(dev, desc[i].addr, min); + if (vu_lduw_p(dev, &desc[i].flags) & VRING_DESC_F_WRITE) { + min = MIN(vu_ldl_p(dev, &desc[i].len), len); + vu_log_write(dev, vu_ldq_p(dev, &desc[i].addr), min); len -= min; } @@ -2772,15 +2773,15 @@ vu_queue_fill(VuDev *dev, VuVirtq *vq, idx = (idx + vq->used_idx) % vq->vring.num; - uelem.id = elem->index; - uelem.len = len; + vu_stl_p(dev, &uelem.id, elem->index); + vu_stl_p(dev, &uelem.len, len); vring_used_write(dev, vq, &uelem, idx); } static inline void vring_used_idx_set(VuDev *dev, VuVirtq *vq, uint16_t val) { - vq->vring.used->idx = val; + vu_stw_p(dev, &vq->vring.used->idx, val); vu_log_write(dev, vq->vring.log_guest_addr + offsetof(struct vring_used, idx), sizeof(vq->vring.used->idx)); -- 2.25.4
