[RFC PATCH 02/10] vhost: push virtqueue area pointers into a user struct

From: Vincent Whitchurch
Date: Wed Sep 29 2021 - 11:11:47 EST

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In order to prepare for allowing vhost to operate on kernel buffers,
push the virtqueue desc/avail/used area pointers down to a new "user"
struct.

No functional change intended.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
---
drivers/vhost/vdpa.c | 6 +--
drivers/vhost/vhost.c | 90 +++++++++++++++++++++----------------------
drivers/vhost/vhost.h | 8 ++--
3 files changed, 53 insertions(+), 51 deletions(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index f41d081777f5..6f05388f5a21 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -400,9 +400,9 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
switch (cmd) {
case VHOST_SET_VRING_ADDR:
if (ops->set_vq_address(vdpa, idx,
- (u64)(uintptr_t)vq->desc,
- (u64)(uintptr_t)vq->avail,
- (u64)(uintptr_t)vq->used))
+ (u64)(uintptr_t)vq->user.desc,
+ (u64)(uintptr_t)vq->user.avail,
+ (u64)(uintptr_t)vq->user.used))
r = -EINVAL;
break;

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 59edb5a1ffe2..108994f386f7 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -46,8 +46,8 @@ enum {
VHOST_MEMORY_F_LOG = 0x1,
};

-#define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
-#define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
+#define vhost_used_event(vq) ((__virtio16 __user *)&vq->user.avail->ring[vq->num])
+#define vhost_avail_event(vq) ((__virtio16 __user *)&vq->user.used->ring[vq->num])

#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
@@ -306,7 +306,7 @@ static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)

bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
{
- return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq);
+ return vq->user.avail && vq->user.desc && vq->user.used && vhost_vq_access_ok(vq);
}
EXPORT_SYMBOL_GPL(vhost_vq_is_setup);

@@ -314,9 +314,9 @@ static void vhost_vq_reset(struct vhost_dev *dev,
struct vhost_virtqueue *vq)
{
vq->num = 1;
- vq->desc = NULL;
- vq->avail = NULL;
- vq->used = NULL;
+ vq->user.desc = NULL;
+ vq->user.avail = NULL;
+ vq->user.used = NULL;
vq->last_avail_idx = 0;
vq->avail_idx = 0;
vq->last_used_idx = 0;
@@ -444,8 +444,8 @@ static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
size_t event __maybe_unused =
vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;

- return sizeof(*vq->avail) +
- sizeof(*vq->avail->ring) * num + event;
+ return sizeof(*vq->user.avail) +
+ sizeof(*vq->user.avail->ring) * num + event;
}

static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
@@ -454,14 +454,14 @@ static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
size_t event __maybe_unused =
vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;

- return sizeof(*vq->used) +
- sizeof(*vq->used->ring) * num + event;
+ return sizeof(*vq->user.used) +
+ sizeof(*vq->user.used->ring) * num + event;
}

static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
unsigned int num)
{
- return sizeof(*vq->desc) * num;
+ return sizeof(*vq->user.desc) * num;
}

void vhost_dev_init(struct vhost_dev *dev,
@@ -959,7 +959,7 @@ static inline int vhost_put_used(struct vhost_virtqueue *vq,
struct vring_used_elem *head, int idx,
int count)
{
- return vhost_copy_to_user(vq, vq->used->ring + idx, head,
+ return vhost_copy_to_user(vq, vq->user.used->ring + idx, head,
count * sizeof(*head));
}

@@ -967,14 +967,14 @@ static inline int vhost_put_used_flags(struct vhost_virtqueue *vq)

{
return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
- &vq->used->flags);
+ &vq->user.used->flags);
}

static inline int vhost_put_used_idx(struct vhost_virtqueue *vq)

{
return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
- &vq->used->idx);
+ &vq->user.used->idx);
}

#define vhost_get_user(vq, x, ptr, type) \
@@ -1018,20 +1018,20 @@ static void vhost_dev_unlock_vqs(struct vhost_dev *d)
static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq,
__virtio16 *idx)
{
- return vhost_get_avail(vq, *idx, &vq->avail->idx);
+ return vhost_get_avail(vq, *idx, &vq->user.avail->idx);
}

static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
__virtio16 *head, int idx)
{
return vhost_get_avail(vq, *head,
- &vq->avail->ring[idx & (vq->num - 1)]);
+ &vq->user.avail->ring[idx & (vq->num - 1)]);
}

static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
__virtio16 *flags)
{
- return vhost_get_avail(vq, *flags, &vq->avail->flags);
+ return vhost_get_avail(vq, *flags, &vq->user.avail->flags);
}

static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
@@ -1043,13 +1043,13 @@ static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
static inline int vhost_get_used_idx(struct vhost_virtqueue *vq,
__virtio16 *idx)
{
- return vhost_get_used(vq, *idx, &vq->used->idx);
+ return vhost_get_used(vq, *idx, &vq->user.used->idx);
}

static inline int vhost_get_desc(struct vhost_virtqueue *vq,
struct vring_desc *desc, int idx)
{
- return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
+ return vhost_copy_from_user(vq, desc, vq->user.desc + idx, sizeof(*desc));
}

static void vhost_iotlb_notify_vq(struct vhost_dev *d,
@@ -1363,12 +1363,12 @@ int vq_meta_prefetch(struct vhost_virtqueue *vq)
if (!vq->iotlb)
return 1;

- return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc,
+ return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->user.desc,
vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
- iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail,
+ iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->user.avail,
vhost_get_avail_size(vq, num),
VHOST_ADDR_AVAIL) &&
- iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used,
+ iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->user.used,
vhost_get_used_size(vq, num), VHOST_ADDR_USED);
}
EXPORT_SYMBOL_GPL(vq_meta_prefetch);
@@ -1412,7 +1412,7 @@ bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
if (!vq_log_access_ok(vq, vq->log_base))
return false;

- return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
+ return vq_access_ok(vq, vq->num, vq->user.desc, vq->user.avail, vq->user.used);
}
EXPORT_SYMBOL_GPL(vhost_vq_access_ok);

@@ -1523,8 +1523,8 @@ static long vhost_vring_set_addr(struct vhost_dev *d,
return -EFAULT;

/* Make sure it's safe to cast pointers to vring types. */
- BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
- BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
+ BUILD_BUG_ON(__alignof__ *vq->user.avail > VRING_AVAIL_ALIGN_SIZE);
+ BUILD_BUG_ON(__alignof__ *vq->user.used > VRING_USED_ALIGN_SIZE);
if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
(a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
(a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
@@ -1548,10 +1548,10 @@ static long vhost_vring_set_addr(struct vhost_dev *d,
}

vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
- vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
- vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
+ vq->user.desc = (void __user *)(unsigned long)a.desc_user_addr;
+ vq->user.avail = (void __user *)(unsigned long)a.avail_user_addr;
vq->log_addr = a.log_guest_addr;
- vq->used = (void __user *)(unsigned long)a.used_user_addr;
+ vq->user.used = (void __user *)(unsigned long)a.used_user_addr;

return 0;
}
@@ -1912,8 +1912,8 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
if (!vq->iotlb)
return log_write(vq->log_base, vq->log_addr + used_offset, len);

- ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
- len, iov, 64, VHOST_ACCESS_WO);
+ ret = translate_desc(vq, (uintptr_t)vq->user.used + used_offset,
+ len, vq->log_iov, 64, VHOST_ACCESS_WO);
if (ret < 0)
return ret;

@@ -1972,9 +1972,9 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
/* Make sure the flag is seen before log. */
smp_wmb();
/* Log used flag write. */
- used = &vq->used->flags;
- log_used(vq, (used - (void __user *)vq->used),
- sizeof vq->used->flags);
+ used = &vq->user.used->flags;
+ log_used(vq, (used - (void __user *)vq->user.used),
+ sizeof vq->user.used->flags);
if (vq->log_ctx)
eventfd_signal(vq->log_ctx, 1);
}
@@ -1991,7 +1991,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
smp_wmb();
/* Log avail event write */
used = vhost_avail_event(vq);
- log_used(vq, (used - (void __user *)vq->used),
+ log_used(vq, (used - (void __user *)vq->user.used),
sizeof *vhost_avail_event(vq));
if (vq->log_ctx)
eventfd_signal(vq->log_ctx, 1);
@@ -2015,14 +2015,14 @@ int vhost_vq_init_access(struct vhost_virtqueue *vq)
goto err;
vq->signalled_used_valid = false;
if (!vq->iotlb &&
- !access_ok(&vq->used->idx, sizeof vq->used->idx)) {
+ !access_ok(&vq->user.used->idx, sizeof vq->user.used->idx)) {
r = -EFAULT;
goto err;
}
r = vhost_get_used_idx(vq, &last_used_idx);
if (r) {
vq_err(vq, "Can't access used idx at %p\n",
- &vq->used->idx);
+ &vq->user.used->idx);
goto err;
}
vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
@@ -2214,7 +2214,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
if (vq->avail_idx == vq->last_avail_idx) {
if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) {
vq_err(vq, "Failed to access avail idx at %p\n",
- &vq->avail->idx);
+ &vq->user.avail->idx);
return -EFAULT;
}
vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
@@ -2242,7 +2242,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) {
vq_err(vq, "Failed to read head: idx %d address %p\n",
last_avail_idx,
- &vq->avail->ring[last_avail_idx % vq->num]);
+ &vq->user.avail->ring[last_avail_idx % vq->num]);
return -EFAULT;
}

@@ -2277,7 +2277,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
ret = vhost_get_desc(vq, &desc, i);
if (unlikely(ret)) {
vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
- i, vq->desc + i);
+ i, vq->user.desc + i);
return -EFAULT;
}
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
@@ -2366,7 +2366,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
int start;

start = vq->last_used_idx & (vq->num - 1);
- used = vq->used->ring + start;
+ used = vq->user.used->ring + start;
if (vhost_put_used(vq, heads, start, count)) {
vq_err(vq, "Failed to write used");
return -EFAULT;
@@ -2375,7 +2375,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
/* Make sure data is seen before log. */
smp_wmb();
/* Log used ring entry write. */
- log_used(vq, ((void __user *)used - (void __user *)vq->used),
+ log_used(vq, ((void __user *)used - (void __user *)vq->user.used),
count * sizeof *used);
}
old = vq->last_used_idx;
@@ -2418,7 +2418,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
smp_wmb();
/* Log used index update. */
log_used(vq, offsetof(struct vring_used, idx),
- sizeof vq->used->idx);
+ sizeof vq->user.used->idx);
if (vq->log_ctx)
eventfd_signal(vq->log_ctx, 1);
}
@@ -2523,7 +2523,7 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
r = vhost_update_used_flags(vq);
if (r) {
vq_err(vq, "Failed to enable notification at %p: %d\n",
- &vq->used->flags, r);
+ &vq->user.used->flags, r);
return false;
}
} else {
@@ -2540,7 +2540,7 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
r = vhost_get_avail_idx(vq, &avail_idx);
if (r) {
vq_err(vq, "Failed to check avail idx at %p: %d\n",
- &vq->avail->idx, r);
+ &vq->user.avail->idx, r);
return false;
}

@@ -2560,7 +2560,7 @@ void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
r = vhost_update_used_flags(vq);
if (r)
vq_err(vq, "Failed to disable notification at %p: %d\n",
- &vq->used->flags, r);
+ &vq->user.used->flags, r);
}
}
EXPORT_SYMBOL_GPL(vhost_disable_notify);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 638bb640d6b4..b1db4ffe75f0 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -72,9 +72,11 @@ struct vhost_virtqueue {
/* The actual ring of buffers. */
struct mutex mutex;
unsigned int num;
- vring_desc_t __user *desc;
- vring_avail_t __user *avail;
- vring_used_t __user *used;
+ struct {
+ vring_desc_t __user *desc;
+ vring_avail_t __user *avail;
+ vring_used_t __user *used;
+ } user;
const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
struct file *kick;
struct vhost_vring_call call_ctx;
--
2.28.0

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Previous message: Vincent Whitchurch: "[RFC PATCH 10/10] selftests: add vhost_kernel tests"
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