reactos/drivers/network/dd/netkvm/virtio/VirtIORing-Packed.c
2020-04-23 16:33:09 +03:00

652 lines
21 KiB
C

/*
* Packed virtio ring manipulation routines
*
* Copyright 2019 Red Hat, Inc.
*
* Authors:
* Yuri Benditovich <ybendito@redhat.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met :
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and / or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of their contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "osdep.h"
#include "virtio_pci.h"
#include "VirtIO.h"
#include "kdebugprint.h"
#include "virtio_ring.h"
#include "windows/virtio_ring_allocation.h"
#include <pshpack1.h>
struct vring_packed_desc_event {
/* Descriptor Ring Change Event Offset/Wrap Counter. */
__le16 off_wrap;
/* Descriptor Ring Change Event Flags. */
__le16 flags;
};
struct vring_packed_desc {
/* Buffer Address. */
__virtio64 addr;
/* Buffer Length. */
__le32 len;
/* Buffer ID. */
__le16 id;
/* The flags depending on descriptor type. */
__le16 flags;
};
#include <poppack.h>
#define BUG_ON(condition) { if (condition) { KeBugCheck(0xE0E1E2E3); }}
#define BAD_RING(vq, fmt, ...) DPrintf(0, "%s: queue %d: " fmt, __FUNCTION__, vq->vq.index, __VA_ARGS__); BUG_ON(true)
/* This marks a buffer as continuing via the next field. */
#define VRING_DESC_F_NEXT 1
/* This marks a buffer as write-only (otherwise read-only). */
#define VRING_DESC_F_WRITE 2
/* This means the buffer contains a list of buffer descriptors. */
#define VRING_DESC_F_INDIRECT 4
/*
* Mark a descriptor as available or used in packed ring.
* Notice: they are defined as shifts instead of shifted values.
*/
#define VRING_PACKED_DESC_F_AVAIL 7
#define VRING_PACKED_DESC_F_USED 15
/* Enable events in packed ring. */
#define VRING_PACKED_EVENT_FLAG_ENABLE 0x0
/* Disable events in packed ring. */
#define VRING_PACKED_EVENT_FLAG_DISABLE 0x1
/*
* Enable events for a specific descriptor in packed ring.
* (as specified by Descriptor Ring Change Event Offset/Wrap Counter).
* Only valid if VIRTIO_RING_F_EVENT_IDX has been negotiated.
*/
#define VRING_PACKED_EVENT_FLAG_DESC 0x2
/*
* Wrap counter bit shift in event suppression structure
* of packed ring.
*/
#define VRING_PACKED_EVENT_F_WRAP_CTR 15
/* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */
/* Assuming a given event_idx value from the other side, if
* we have just incremented index from old to new_idx,
* should we trigger an event?
*/
static inline bool vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
{
/* Note: Xen has similar logic for notification hold-off
* in include/xen/interface/io/ring.h with req_event and req_prod
* corresponding to event_idx + 1 and new_idx respectively.
* Note also that req_event and req_prod in Xen start at 1,
* event indexes in virtio start at 0. */
return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
}
struct vring_desc_state_packed {
void *data; /* Data for callback. */
u16 num; /* Descriptor list length. */
u16 next; /* The next desc state in a list. */
u16 last; /* The last desc state in a list. */
};
struct virtqueue_packed {
struct virtqueue vq;
/* Number we've added since last sync. */
unsigned int num_added;
/* Head of free buffer list. */
unsigned int free_head;
/* Number of free descriptors */
unsigned int num_free;
/* Last used index we've seen. */
u16 last_used_idx;
/* Avail used flags. */
u16 avail_used_flags;
struct
{
/* Driver ring wrap counter. */
bool avail_wrap_counter;
/* Device ring wrap counter. */
bool used_wrap_counter;
/* Index of the next avail descriptor. */
u16 next_avail_idx;
/*
* Last written value to driver->flags in
* guest byte order.
*/
u16 event_flags_shadow;
struct {
unsigned int num;
struct vring_packed_desc *desc;
struct vring_packed_desc_event *driver;
struct vring_packed_desc_event *device;
} vring;
/* Per-descriptor state. */
struct vring_desc_state_packed *desc_state;
} packed;
struct vring_desc_state_packed desc_states[];
};
#define packedvq(vq) ((struct virtqueue_packed *)vq)
unsigned int vring_control_block_size_packed(u16 qsize)
{
return sizeof(struct virtqueue_packed) + sizeof(struct vring_desc_state_packed) * qsize;
}
unsigned long vring_size_packed(unsigned int num, unsigned long align)
{
/* array of descriptors */
unsigned long res = num * sizeof(struct vring_packed_desc);
/* driver and device event */
res += 2 * sizeof(struct vring_packed_desc_event);
return res;
}
static int virtqueue_add_buf_packed(
struct virtqueue *_vq, /* the queue */
struct scatterlist sg[], /* sg array of length out + in */
unsigned int out, /* number of driver->device buffer descriptors in sg */
unsigned int in, /* number of device->driver buffer descriptors in sg */
void *opaque, /* later returned from virtqueue_get_buf */
void *va_indirect, /* VA of the indirect page or NULL */
ULONGLONG phys_indirect) /* PA of the indirect page or 0 */
{
struct virtqueue_packed *vq = packedvq(_vq);
unsigned int descs_used;
struct vring_packed_desc *desc;
u16 head, id, i;
descs_used = out + in;
head = vq->packed.next_avail_idx;
id = (u16)vq->free_head;
BUG_ON(descs_used == 0);
BUG_ON(id >= vq->packed.vring.num);
if (va_indirect && vq->num_free > 0) {
desc = va_indirect;
for (i = 0; i < descs_used; i++) {
desc[i].flags = i < out ? 0 : VRING_DESC_F_WRITE;
desc[i].addr = sg[i].physAddr.QuadPart;
desc[i].len = sg[i].length;
}
vq->packed.vring.desc[head].addr = phys_indirect;
vq->packed.vring.desc[head].len = descs_used * sizeof(struct vring_packed_desc);
vq->packed.vring.desc[head].id = id;
KeMemoryBarrier();
vq->packed.vring.desc[head].flags = VRING_DESC_F_INDIRECT | vq->avail_used_flags;
DPrintf(5, "Added buffer head %i to Q%d\n", head, vq->vq.index);
head++;
if (head >= vq->packed.vring.num) {
head = 0;
vq->packed.avail_wrap_counter ^= 1;
vq->avail_used_flags ^=
1 << VRING_PACKED_DESC_F_AVAIL |
1 << VRING_PACKED_DESC_F_USED;
}
vq->packed.next_avail_idx = head;
/* We're using some buffers from the free list. */
vq->num_free -= 1;
vq->num_added += 1;
vq->free_head = vq->packed.desc_state[id].next;
/* Store token and indirect buffer state. */
vq->packed.desc_state[id].num = 1;
vq->packed.desc_state[id].data = opaque;
vq->packed.desc_state[id].last = id;
} else {
unsigned int n;
u16 curr, prev, head_flags;
if (vq->num_free < descs_used) {
DPrintf(6, "Can't add buffer to Q%d\n", vq->vq.index);
return -ENOSPC;
}
desc = vq->packed.vring.desc;
i = head;
curr = id;
for (n = 0; n < descs_used; n++) {
u16 flags = vq->avail_used_flags;
flags |= n < out ? 0 : VRING_DESC_F_WRITE;
if (n != descs_used - 1) {
flags |= VRING_DESC_F_NEXT;
}
desc[i].addr = sg[n].physAddr.QuadPart;
desc[i].len = sg[n].length;
desc[i].id = id;
if (n == 0) {
head_flags = flags;
}
else {
desc[i].flags = flags;
}
prev = curr;
curr = vq->packed.desc_state[curr].next;
if (++i >= vq->packed.vring.num) {
i = 0;
vq->avail_used_flags ^=
1 << VRING_PACKED_DESC_F_AVAIL |
1 << VRING_PACKED_DESC_F_USED;
}
}
if (i < head)
vq->packed.avail_wrap_counter ^= 1;
/* We're using some buffers from the free list. */
vq->num_free -= descs_used;
/* Update free pointer */
vq->packed.next_avail_idx = i;
vq->free_head = curr;
/* Store token. */
vq->packed.desc_state[id].num = (u16)descs_used;
vq->packed.desc_state[id].data = opaque;
vq->packed.desc_state[id].last = prev;
/*
* A driver MUST NOT make the first descriptor in the list
* available before all subsequent descriptors comprising
* the list are made available.
*/
KeMemoryBarrier();
vq->packed.vring.desc[head].flags = head_flags;
vq->num_added += descs_used;
DPrintf(5, "Added buffer head @%i+%d to Q%d\n", head, descs_used, vq->vq.index);
}
return 0;
}
static void detach_buf_packed(struct virtqueue_packed *vq, unsigned int id)
{
struct vring_desc_state_packed *state = &vq->packed.desc_state[id];
/* Clear data ptr. */
state->data = NULL;
vq->packed.desc_state[state->last].next = (u16)vq->free_head;
vq->free_head = id;
vq->num_free += state->num;
}
static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
unsigned int i;
void *buf;
for (i = 0; i < vq->packed.vring.num; i++) {
if (!vq->packed.desc_state[i].data)
continue;
/* detach_buf clears data, so grab it now. */
buf = vq->packed.desc_state[i].data;
detach_buf_packed(vq, i);
return buf;
}
/* That should have freed everything. */
BUG_ON(vq->num_free != vq->packed.vring.num);
return NULL;
}
static void virtqueue_disable_cb_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
if (vq->packed.event_flags_shadow != VRING_PACKED_EVENT_FLAG_DISABLE) {
vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
vq->packed.vring.driver->flags = vq->packed.event_flags_shadow;
}
}
static inline bool is_used_desc_packed(const struct virtqueue_packed *vq,
u16 idx, bool used_wrap_counter)
{
bool avail, used;
u16 flags;
flags = vq->packed.vring.desc[idx].flags;
avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL));
used = !!(flags & (1 << VRING_PACKED_DESC_F_USED));
return avail == used && used == used_wrap_counter;
}
static inline bool virtqueue_poll_packed(struct virtqueue_packed *vq, u16 off_wrap)
{
bool wrap_counter;
u16 used_idx;
KeMemoryBarrier();
wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR;
used_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR);
return is_used_desc_packed(vq, used_idx, wrap_counter);
}
static inline unsigned virtqueue_enable_cb_prepare_packed(struct virtqueue_packed *vq)
{
bool event_suppression_enabled = vq->vq.vdev->event_suppression_enabled;
/*
* We optimistically turn back on interrupts, then check if there was
* more to do.
*/
if (event_suppression_enabled) {
vq->packed.vring.driver->off_wrap =
vq->last_used_idx |
(vq->packed.used_wrap_counter <<
VRING_PACKED_EVENT_F_WRAP_CTR);
/*
* We need to update event offset and event wrap
* counter first before updating event flags.
*/
KeMemoryBarrier();
}
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) {
vq->packed.event_flags_shadow = event_suppression_enabled ?
VRING_PACKED_EVENT_FLAG_DESC :
VRING_PACKED_EVENT_FLAG_ENABLE;
vq->packed.vring.driver->flags = vq->packed.event_flags_shadow;
}
return vq->last_used_idx | ((u16)vq->packed.used_wrap_counter <<
VRING_PACKED_EVENT_F_WRAP_CTR);
}
static bool virtqueue_enable_cb_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
unsigned last_used_idx = virtqueue_enable_cb_prepare_packed(vq);
return !virtqueue_poll_packed(vq, (u16)last_used_idx);
}
static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
bool event_suppression_enabled = vq->vq.vdev->event_suppression_enabled;
u16 used_idx, wrap_counter;
u16 bufs;
/*
* We optimistically turn back on interrupts, then check if there was
* more to do.
*/
if (event_suppression_enabled) {
/* TODO: tune this threshold */
bufs = (vq->packed.vring.num - vq->num_free) * 3 / 4;
wrap_counter = vq->packed.used_wrap_counter;
used_idx = vq->last_used_idx + bufs;
if (used_idx >= vq->packed.vring.num) {
used_idx -= (u16)vq->packed.vring.num;
wrap_counter ^= 1;
}
vq->packed.vring.driver->off_wrap = used_idx |
(wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR);
/*
* We need to update event offset and event wrap
* counter first before updating event flags.
*/
KeMemoryBarrier();
}
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) {
vq->packed.event_flags_shadow = event_suppression_enabled ?
VRING_PACKED_EVENT_FLAG_DESC :
VRING_PACKED_EVENT_FLAG_ENABLE;
vq->packed.vring.driver->flags = vq->packed.event_flags_shadow;
}
/*
* We need to update event suppression structure first
* before re-checking for more used buffers.
*/
KeMemoryBarrier();
if (is_used_desc_packed(vq,
vq->last_used_idx,
vq->packed.used_wrap_counter)) {
return false;
}
return true;
}
static BOOLEAN virtqueue_is_interrupt_enabled_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
return vq->packed.event_flags_shadow & VRING_PACKED_EVENT_FLAG_DISABLE;
}
static void virtqueue_shutdown_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
unsigned int num = vq->packed.vring.num;
void *pages = vq->packed.vring.desc;
unsigned int vring_align = _vq->vdev->addr ? PAGE_SIZE : SMP_CACHE_BYTES;
RtlZeroMemory(pages, vring_size_packed(num, vring_align));
vring_new_virtqueue_packed(
_vq->index,
num,
vring_align,
_vq->vdev,
pages,
_vq->notification_cb,
_vq);
}
static inline bool more_used_packed(const struct virtqueue_packed *vq)
{
return is_used_desc_packed(vq, vq->last_used_idx,
vq->packed.used_wrap_counter);
}
static void *virtqueue_get_buf_packed(
struct virtqueue *_vq, /* the queue */
unsigned int *len) /* number of bytes returned by the device */
{
struct virtqueue_packed *vq = packedvq(_vq);
u16 last_used, id;
void *ret;
if (!more_used_packed(vq)) {
DPrintf(6, "%s: No more buffers in queue\n", __FUNCTION__);
return NULL;
}
/* Only get used elements after they have been exposed by host. */
KeMemoryBarrier();
last_used = vq->last_used_idx;
id = vq->packed.vring.desc[last_used].id;
*len = vq->packed.vring.desc[last_used].len;
if (id >= vq->packed.vring.num) {
BAD_RING(vq, "id %u out of range\n", id);
return NULL;
}
if (!vq->packed.desc_state[id].data) {
BAD_RING(vq, "id %u is not a head!\n", id);
return NULL;
}
/* detach_buf_packed clears data, so grab it now. */
ret = vq->packed.desc_state[id].data;
detach_buf_packed(vq, id);
vq->last_used_idx += vq->packed.desc_state[id].num;
if (vq->last_used_idx >= vq->packed.vring.num) {
vq->last_used_idx -= (u16)vq->packed.vring.num;
vq->packed.used_wrap_counter ^= 1;
}
/*
* If we expect an interrupt for the next entry, tell host
* by writing event index and flush out the write before
* the read in the next get_buf call.
*/
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DESC) {
vq->packed.vring.driver->off_wrap = vq->last_used_idx |
((u16)vq->packed.used_wrap_counter <<
VRING_PACKED_EVENT_F_WRAP_CTR);
KeMemoryBarrier();
}
return ret;
}
static BOOLEAN virtqueue_has_buf_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
return more_used_packed(vq);
}
static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
u16 new, old, off_wrap, flags, wrap_counter, event_idx;
bool needs_kick;
union {
struct {
__le16 off_wrap;
__le16 flags;
};
u32 value32;
} snapshot;
/*
* We need to expose the new flags value before checking notification
* suppressions.
*/
KeMemoryBarrier();
old = vq->packed.next_avail_idx - vq->num_added;
new = vq->packed.next_avail_idx;
vq->num_added = 0;
snapshot.value32 = *(u32 *)vq->packed.vring.device;
flags = snapshot.flags;
if (flags != VRING_PACKED_EVENT_FLAG_DESC) {
needs_kick = (flags != VRING_PACKED_EVENT_FLAG_DISABLE);
goto out;
}
off_wrap = snapshot.off_wrap;
wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR;
event_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR);
if (wrap_counter != vq->packed.avail_wrap_counter)
event_idx -= (u16)vq->packed.vring.num;
needs_kick = vring_need_event(event_idx, new, old);
out:
return needs_kick;
}
static void virtqueue_kick_always_packed(struct virtqueue *_vq)
{
struct virtqueue_packed *vq = packedvq(_vq);
KeMemoryBarrier();
vq->num_added = 0;
virtqueue_notify(_vq);
}
/* Initializes a new virtqueue using already allocated memory */
struct virtqueue *vring_new_virtqueue_packed(
unsigned int index, /* virtqueue index */
unsigned int num, /* virtqueue size (always a power of 2) */
unsigned int vring_align, /* vring alignment requirement */
VirtIODevice *vdev, /* the virtio device owning the queue */
void *pages, /* vring memory */
void(*notify)(struct virtqueue *), /* notification callback */
void *control) /* virtqueue memory */
{
struct virtqueue_packed *vq = packedvq(control);
unsigned int i;
vq->vq.vdev = vdev;
vq->vq.notification_cb = notify;
vq->vq.index = index;
vq->vq.avail_va = (u8 *)pages + num * sizeof(struct vring_packed_desc);
vq->vq.used_va = (u8 *)vq->vq.avail_va + sizeof(struct vring_packed_desc_event);
/* initialize the ring */
vq->packed.vring.num = num;
vq->packed.vring.desc = pages;
vq->packed.vring.driver = vq->vq.avail_va;
vq->packed.vring.device = vq->vq.used_va;
vq->num_free = num;
vq->free_head = 0;
vq->num_added = 0;
vq->packed.avail_wrap_counter = 1;
vq->packed.used_wrap_counter = 1;
vq->last_used_idx = 0;
vq->avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
vq->packed.next_avail_idx = 0;
vq->packed.event_flags_shadow = 0;
vq->packed.desc_state = vq->desc_states;
RtlZeroMemory(vq->packed.desc_state, num * sizeof(*vq->packed.desc_state));
for (i = 0; i < num - 1; i++) {
vq->packed.desc_state[i].next = i + 1;
}
vq->vq.add_buf = virtqueue_add_buf_packed;
vq->vq.detach_unused_buf = virtqueue_detach_unused_buf_packed;
vq->vq.disable_cb = virtqueue_disable_cb_packed;
vq->vq.enable_cb = virtqueue_enable_cb_packed;
vq->vq.enable_cb_delayed = virtqueue_enable_cb_delayed_packed;
vq->vq.get_buf = virtqueue_get_buf_packed;
vq->vq.has_buf = virtqueue_has_buf_packed;
vq->vq.is_interrupt_enabled = virtqueue_is_interrupt_enabled_packed;
vq->vq.kick_always = virtqueue_kick_always_packed;
vq->vq.kick_prepare = virtqueue_kick_prepare_packed;
vq->vq.shutdown = virtqueue_shutdown_packed;
return &vq->vq;
}