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qemu/libvhost-user-handle-endianness-as-manda.patch

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From: Marc Hartmayer <mhartmay@linux.ibm.com>
Date: Tue, 1 Sep 2020 17:00:19 +0200
Subject: libvhost-user: handle endianness as mandated by the spec
Git-commit: 2ffc54708087c6e524297957be2fc5d543abb767
References: jsc#sle-14618
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]
and fence legacy virtio, as there is no safe way to figure out the
needed endianness conversions for all cases. The fencing of legacy
virtio devices is done in `vu_set_features_exec`.
[1] https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-210003
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Message-id: 20200901150019.29229-3-mhartmay@linux.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Liang Yan <lyan@suse.com>
---
contrib/libvhost-user/libvhost-user.c | 77 +++++++++++++++------------
1 file changed, 43 insertions(+), 34 deletions(-)
diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index 53f16bdf082c758e795859b71d22..e2238a0400c9630be1cdab30788c 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -42,6 +42,7 @@
#include "qemu/atomic.h"
#include "qemu/osdep.h"
+#include "qemu/bswap.h"
#include "qemu/memfd.h"
#include "libvhost-user.h"
@@ -539,6 +540,14 @@ vu_set_features_exec(VuDev *dev, VhostUserMsg *vmsg)
DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
dev->features = vmsg->payload.u64;
+ if (!vu_has_feature(dev, VIRTIO_F_VERSION_1)) {
+ /*
+ * We only support devices conforming to VIRTIO 1.0 or
+ * later
+ */
+ vu_panic(dev, "virtio legacy devices aren't supported by libvhost-user");
+ return false;
+ }
if (!(dev->features & VHOST_USER_F_PROTOCOL_FEATURES)) {
vu_set_enable_all_rings(dev, true);
@@ -1074,7 +1083,7 @@ vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vmsg)
return false;
}
- vq->used_idx = vq->vring.used->idx;
+ vq->used_idx = lduw_le_p(&vq->vring.used->idx);
if (vq->last_avail_idx != vq->used_idx) {
bool resume = dev->iface->queue_is_processed_in_order &&
@@ -1191,7 +1200,7 @@ vu_check_queue_inflights(VuDev *dev, VuVirtq *vq)
return 0;
}
- vq->used_idx = vq->vring.used->idx;
+ vq->used_idx = lduw_le_p(&vq->vring.used->idx);
vq->resubmit_num = 0;
vq->resubmit_list = NULL;
vq->counter = 0;
@@ -2021,13 +2030,13 @@ vu_queue_started(const VuDev *dev, const VuVirtq *vq)
static inline uint16_t
vring_avail_flags(VuVirtq *vq)
{
- return vq->vring.avail->flags;
+ return lduw_le_p(&vq->vring.avail->flags);
}
static inline uint16_t
vring_avail_idx(VuVirtq *vq)
{
- vq->shadow_avail_idx = vq->vring.avail->idx;
+ vq->shadow_avail_idx = lduw_le_p(&vq->vring.avail->idx);
return vq->shadow_avail_idx;
}
@@ -2035,7 +2044,7 @@ vring_avail_idx(VuVirtq *vq)
static inline uint16_t
vring_avail_ring(VuVirtq *vq, int i)
{
- return vq->vring.avail->ring[i];
+ return lduw_le_p(&vq->vring.avail->ring[i]);
}
static inline uint16_t
@@ -2123,12 +2132,12 @@ 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 (!(lduw_le_p(&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 = lduw_le_p(&desc[i].next);
/* Make sure compiler knows to grab that: we don't want it changing! */
smp_wmb();
@@ -2171,8 +2180,8 @@ 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 (lduw_le_p(&desc[i].flags) & VRING_DESC_F_INDIRECT) {
+ if (ldl_le_p(&desc[i].len) % sizeof(struct vring_desc)) {
vu_panic(dev, "Invalid size for indirect buffer table");
goto err;
}
@@ -2185,8 +2194,8 @@ 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 = ldq_le_p(&desc[i].addr);
+ desc_len = ldl_le_p(&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 +2222,10 @@ 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 (lduw_le_p(&desc[i].flags) & VRING_DESC_F_WRITE) {
+ in_total += ldl_le_p(&desc[i].len);
} else {
- out_total += desc[i].len;
+ out_total += ldl_le_p(&desc[i].len);
}
if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
goto done;
@@ -2367,7 +2376,7 @@ vring_used_flags_set_bit(VuVirtq *vq, int mask)
flags = (uint16_t *)((char*)vq->vring.used +
offsetof(struct vring_used, flags));
- *flags |= mask;
+ stw_le_p(flags, lduw_le_p(flags) | mask);
}
static inline void
@@ -2377,7 +2386,7 @@ vring_used_flags_unset_bit(VuVirtq *vq, int mask)
flags = (uint16_t *)((char*)vq->vring.used +
offsetof(struct vring_used, flags));
- *flags &= ~mask;
+ stw_le_p(flags, lduw_le_p(flags) & ~mask);
}
static inline void
@@ -2387,7 +2396,7 @@ vring_set_avail_event(VuVirtq *vq, uint16_t val)
return;
}
- *((uint16_t *) &vq->vring.used->ring[vq->vring.num]) = val;
+ stw_le_p(&vq->vring.used->ring[vq->vring.num], val);
}
void
@@ -2476,14 +2485,14 @@ 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 (lduw_le_p(&desc[i].flags) & VRING_DESC_F_INDIRECT) {
+ if (ldl_le_p(&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 = ldq_le_p(&desc[i].addr);
+ desc_len = ldl_le_p(&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 +2514,10 @@ 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 (lduw_le_p(&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);
+ ldq_le_p(&desc[i].addr), ldl_le_p(&desc[i].len));
} else {
if (in_num) {
vu_panic(dev, "Incorrect order for descriptors");
@@ -2516,7 +2525,7 @@ 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);
+ ldq_le_p(&desc[i].addr), ldl_le_p(&desc[i].len));
}
/* If we've got too many, that implies a descriptor loop. */
@@ -2712,14 +2721,14 @@ 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 (lduw_le_p(&desc[i].flags) & VRING_DESC_F_INDIRECT) {
+ if (ldl_le_p(&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 = ldq_le_p(&desc[i].addr);
+ desc_len = ldl_le_p(&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 +2754,9 @@ 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 (lduw_le_p(&desc[i].flags) & VRING_DESC_F_WRITE) {
+ min = MIN(ldl_le_p(&desc[i].len), len);
+ vu_log_write(dev, ldq_le_p(&desc[i].addr), min);
len -= min;
}
@@ -2772,15 +2781,15 @@ vu_queue_fill(VuDev *dev, VuVirtq *vq,
idx = (idx + vq->used_idx) % vq->vring.num;
- uelem.id = elem->index;
- uelem.len = len;
+ stl_le_p(&uelem.id, elem->index);
+ stl_le_p(&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;
+ stw_le_p(&vq->vring.used->idx, val);
vu_log_write(dev,
vq->vring.log_guest_addr + offsetof(struct vring_used, idx),
sizeof(vq->vring.used->idx));
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