vDPA supports the possibility to use user VA in the iotlb messages.
So, let's add support for user VA in vringh to use it in the vDPA
simulators.
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
Notes:
v4:
- used uintptr_t for `io_addr` [Eugenio]
- added `io_addr` and `io_len` variables in iotlb_translate
- avoided overflow doing `map->addr - map->start + addr` [Jason]
- removed `is_iovec` field from struct iotlb_vec [Jason]
- added vringh_init_iotlb_va() [Jason]
v3:
- refactored avoiding code duplication [Eugenio]
v2:
- replace kmap_atomic() with kmap_local_page() [see previous patch]
- fix cast warnings when build with W=1 C=1
include/linux/vringh.h | 9 +++
drivers/vhost/vringh.c | 171 +++++++++++++++++++++++++++++++++--------
2 files changed, 148 insertions(+), 32 deletions(-)
diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index 1991a02c6431..b4edfadf5479 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -32,6 +32,9 @@ struct vringh {
/* Can we get away with weak barriers? */
bool weak_barriers;
+ /* Use user's VA */
+ bool use_va;
+
/* Last available index we saw (ie. where we're up to). */
u16 last_avail_idx;
@@ -284,6 +287,12 @@ int vringh_init_iotlb(struct vringh *vrh, u64 features,
struct vring_avail *avail,
struct vring_used *used);
+int vringh_init_iotlb_va(struct vringh *vrh, u64 features,
+ unsigned int num, bool weak_barriers,
+ struct vring_desc *desc,
+ struct vring_avail *avail,
+ struct vring_used *used);
+
int vringh_getdesc_iotlb(struct vringh *vrh,
struct vringh_kiov *riov,
struct vringh_kiov *wiov,
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 4aee230f7622..771c2aba8aac 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -1094,10 +1094,17 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
#if IS_REACHABLE(CONFIG_VHOST_IOTLB)
+struct iotlb_vec {
+ union {
+ struct iovec *iovec;
+ struct bio_vec *bvec;
+ } iov;
+ size_t count;
+};
+
static int iotlb_translate(const struct vringh *vrh,
u64 addr, u64 len, u64 *translated,
- struct bio_vec iov[],
- int iov_size, u32 perm)
+ struct iotlb_vec *ivec, u32 perm)
{
struct vhost_iotlb_map *map;
struct vhost_iotlb *iotlb = vrh->iotlb;
@@ -1107,9 +1114,11 @@ static int iotlb_translate(const struct vringh *vrh,
spin_lock(vrh->iotlb_lock);
while (len > s) {
- u64 size, pa, pfn;
+ uintptr_t io_addr;
+ size_t io_len;
+ u64 size;
- if (unlikely(ret >= iov_size)) {
+ if (unlikely(ret >= ivec->count)) {
ret = -ENOBUFS;
break;
}
@@ -1124,10 +1133,22 @@ static int iotlb_translate(const struct vringh *vrh,
}
size = map->size - addr + map->start;
- pa = map->addr + addr - map->start;
- pfn = pa >> PAGE_SHIFT;
- bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
- pa & (PAGE_SIZE - 1));
+ io_len = min(len - s, size);
+ io_addr = map->addr - map->start + addr;
+
+ if (vrh->use_va) {
+ struct iovec *iovec = ivec->iov.iovec;
+
+ iovec[ret].iov_len = io_len;
+ iovec[ret].iov_base = (void __user *)io_addr;
+ } else {
+ u64 pfn = io_addr >> PAGE_SHIFT;
+ struct bio_vec *bvec = ivec->iov.bvec;
+
+ bvec_set_page(&bvec[ret], pfn_to_page(pfn), io_len,
+ io_addr & (PAGE_SIZE - 1));
+ }
+
s += size;
addr += size;
++ret;
@@ -1146,23 +1167,36 @@ static int iotlb_translate(const struct vringh *vrh,
static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
void *src, size_t len)
{
+ struct iotlb_vec ivec;
+ union {
+ struct iovec iovec[IOTLB_IOV_STRIDE];
+ struct bio_vec bvec[IOTLB_IOV_STRIDE];
+ } iov;
u64 total_translated = 0;
+ ivec.iov.iovec = iov.iovec;
+ ivec.count = IOTLB_IOV_STRIDE;
+
while (total_translated < len) {
- struct bio_vec iov[IOTLB_IOV_STRIDE];
struct iov_iter iter;
u64 translated;
int ret;
ret = iotlb_translate(vrh, (u64)(uintptr_t)src,
len - total_translated, &translated,
- iov, ARRAY_SIZE(iov), VHOST_MAP_RO);
+ &ivec, VHOST_MAP_RO);
if (ret == -ENOBUFS)
- ret = ARRAY_SIZE(iov);
+ ret = IOTLB_IOV_STRIDE;
else if (ret < 0)
return ret;
- iov_iter_bvec(&iter, ITER_SOURCE, iov, ret, translated);
+ if (vrh->use_va) {
+ iov_iter_init(&iter, ITER_SOURCE, ivec.iov.iovec, ret,
+ translated);
+ } else {
+ iov_iter_bvec(&iter, ITER_SOURCE, ivec.iov.bvec, ret,
+ translated);
+ }
ret = copy_from_iter(dst, translated, &iter);
if (ret < 0)
@@ -1179,23 +1213,36 @@ static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
void *src, size_t len)
{
+ struct iotlb_vec ivec;
+ union {
+ struct iovec iovec[IOTLB_IOV_STRIDE];
+ struct bio_vec bvec[IOTLB_IOV_STRIDE];
+ } iov;
u64 total_translated = 0;
+ ivec.iov.iovec = iov.iovec;
+ ivec.count = IOTLB_IOV_STRIDE;
+
while (total_translated < len) {
- struct bio_vec iov[IOTLB_IOV_STRIDE];
struct iov_iter iter;
u64 translated;
int ret;
ret = iotlb_translate(vrh, (u64)(uintptr_t)dst,
len - total_translated, &translated,
- iov, ARRAY_SIZE(iov), VHOST_MAP_WO);
+ &ivec, VHOST_MAP_WO);
if (ret == -ENOBUFS)
- ret = ARRAY_SIZE(iov);
+ ret = IOTLB_IOV_STRIDE;
else if (ret < 0)
return ret;
- iov_iter_bvec(&iter, ITER_DEST, iov, ret, translated);
+ if (vrh->use_va) {
+ iov_iter_init(&iter, ITER_DEST, ivec.iov.iovec, ret,
+ translated);
+ } else {
+ iov_iter_bvec(&iter, ITER_DEST, ivec.iov.bvec, ret,
+ translated);
+ }
ret = copy_to_iter(src, translated, &iter);
if (ret < 0)
@@ -1212,20 +1259,36 @@ static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
static inline int getu16_iotlb(const struct vringh *vrh,
u16 *val, const __virtio16 *p)
{
- struct bio_vec iov;
- void *kaddr, *from;
+ struct iotlb_vec ivec;
+ union {
+ struct iovec iovec[1];
+ struct bio_vec bvec[1];
+ } iov;
+ __virtio16 tmp;
int ret;
+ ivec.iov.iovec = iov.iovec;
+ ivec.count = 1;
+
/* Atomic read is needed for getu16 */
- ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
- &iov, 1, VHOST_MAP_RO);
+ ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
+ NULL, &ivec, VHOST_MAP_RO);
if (ret < 0)
return ret;
- kaddr = kmap_local_page(iov.bv_page);
- from = kaddr + iov.bv_offset;
- *val = vringh16_to_cpu(vrh, READ_ONCE(*(__virtio16 *)from));
- kunmap_local(kaddr);
+ if (vrh->use_va) {
+ ret = __get_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
+ if (ret)
+ return ret;
+ } else {
+ void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
+ void *from = kaddr + ivec.iov.bvec[0].bv_offset;
+
+ tmp = READ_ONCE(*(__virtio16 *)from);
+ kunmap_local(kaddr);
+ }
+
+ *val = vringh16_to_cpu(vrh, tmp);
return 0;
}
@@ -1233,20 +1296,36 @@ static inline int getu16_iotlb(const struct vringh *vrh,
static inline int putu16_iotlb(const struct vringh *vrh,
__virtio16 *p, u16 val)
{
- struct bio_vec iov;
- void *kaddr, *to;
+ struct iotlb_vec ivec;
+ union {
+ struct iovec iovec;
+ struct bio_vec bvec;
+ } iov;
+ __virtio16 tmp;
int ret;
+ ivec.iov.iovec = &iov.iovec;
+ ivec.count = 1;
+
/* Atomic write is needed for putu16 */
- ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
- &iov, 1, VHOST_MAP_WO);
+ ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
+ NULL, &ivec, VHOST_MAP_RO);
if (ret < 0)
return ret;
- kaddr = kmap_local_page(iov.bv_page);
- to = kaddr + iov.bv_offset;
- WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val));
- kunmap_local(kaddr);
+ tmp = cpu_to_vringh16(vrh, val);
+
+ if (vrh->use_va) {
+ ret = __put_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
+ if (ret)
+ return ret;
+ } else {
+ void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
+ void *to = kaddr + ivec.iov.bvec[0].bv_offset;
+
+ WRITE_ONCE(*(__virtio16 *)to, tmp);
+ kunmap_local(kaddr);
+ }
return 0;
}
@@ -1320,11 +1399,39 @@ int vringh_init_iotlb(struct vringh *vrh, u64 features,
struct vring_avail *avail,
struct vring_used *used)
{
+ vrh->use_va = false;
+
return vringh_init_kern(vrh, features, num, weak_barriers,
desc, avail, used);
}
EXPORT_SYMBOL(vringh_init_iotlb);
+/**
+ * vringh_init_iotlb_va - initialize a vringh for a ring with IOTLB containing
+ * user VA.
+ * @vrh: the vringh to initialize.
+ * @features: the feature bits for this ring.
+ * @num: the number of elements.
+ * @weak_barriers: true if we only need memory barriers, not I/O.
+ * @desc: the userpace descriptor pointer.
+ * @avail: the userpace avail pointer.
+ * @used: the userpace used pointer.
+ *
+ * Returns an error if num is invalid.
+ */
+int vringh_init_iotlb_va(struct vringh *vrh, u64 features,
+ unsigned int num, bool weak_barriers,
+ struct vring_desc *desc,
+ struct vring_avail *avail,
+ struct vring_used *used)
+{
+ vrh->use_va = true;
+
+ return vringh_init_kern(vrh, features, num, weak_barriers,
+ desc, avail, used);
+}
+EXPORT_SYMBOL(vringh_init_iotlb_va);
+
/**
* vringh_set_iotlb - initialize a vringh for a ring with IOTLB.
* @vrh: the vring
--
2.39.2
