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8118f0950f
qemu/hw/virtio/virtio.c
Alexander Graf 8118f0950f migration: Append JSON description of migration stream 
One of the annoyances of the current migration format is the fact that
it's not self-describing. In fact, it's not properly describing at all.
Some code randomly scattered throughout QEMU elaborates roughly how to
read and write a stream of bytes.

We discussed an idea during KVM Forum 2013 to add a JSON description of
the migration protocol itself to the migration stream. This patch
adds a section after the VM_END migration end marker that contains
description data on what the device sections of the stream are composed of.

This approach is backwards compatible with any QEMU version reading the
stream, because QEMU just stops reading after the VM_END marker and ignores
any data following it.

With an additional external program this allows us to decipher the
contents of any migration stream and hopefully make migration bugs easier
to track down.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2015-02-05 17:16:14 +01:00

1359 lines
36 KiB
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/*
* Virtio Support
*
* Copyright IBM, Corp. 2007
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include <inttypes.h>
#include "trace.h"
#include "exec/address-spaces.h"
#include "qemu/error-report.h"
#include "hw/virtio/virtio.h"
#include "qemu/atomic.h"
#include "hw/virtio/virtio-bus.h"
#include "migration/migration.h"
#include "hw/virtio/virtio-access.h"
/*
* The alignment to use between consumer and producer parts of vring.
* x86 pagesize again. This is the default, used by transports like PCI
* which don't provide a means for the guest to tell the host the alignment.
*/
#define VIRTIO_PCI_VRING_ALIGN 4096
typedef struct VRingDesc
{
uint64_t addr;
uint32_t len;
uint16_t flags;
uint16_t next;
} VRingDesc;
typedef struct VRingAvail
{
uint16_t flags;
uint16_t idx;
uint16_t ring[0];
} VRingAvail;
typedef struct VRingUsedElem
{
uint32_t id;
uint32_t len;
} VRingUsedElem;
typedef struct VRingUsed
{
uint16_t flags;
uint16_t idx;
VRingUsedElem ring[0];
} VRingUsed;
typedef struct VRing
{
unsigned int num;
unsigned int align;
hwaddr desc;
hwaddr avail;
hwaddr used;
} VRing;
struct VirtQueue
{
VRing vring;
hwaddr pa;
uint16_t last_avail_idx;
/* Last used index value we have signalled on */
uint16_t signalled_used;
/* Last used index value we have signalled on */
bool signalled_used_valid;
/* Notification enabled? */
bool notification;
uint16_t queue_index;
int inuse;
uint16_t vector;
void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
VirtIODevice *vdev;
EventNotifier guest_notifier;
EventNotifier host_notifier;
};
/* virt queue functions */
static void virtqueue_init(VirtQueue *vq)
{
hwaddr pa = vq->pa;
vq->vring.desc = pa;
vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc);
vq->vring.used = vring_align(vq->vring.avail +
offsetof(VRingAvail, ring[vq->vring.num]),
vq->vring.align);
}
static inline uint64_t vring_desc_addr(VirtIODevice *vdev, hwaddr desc_pa,
int i)
{
hwaddr pa;
pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, addr);
return virtio_ldq_phys(vdev, pa);
}
static inline uint32_t vring_desc_len(VirtIODevice *vdev, hwaddr desc_pa, int i)
{
hwaddr pa;
pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, len);
return virtio_ldl_phys(vdev, pa);
}
static inline uint16_t vring_desc_flags(VirtIODevice *vdev, hwaddr desc_pa,
int i)
{
hwaddr pa;
pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, flags);
return virtio_lduw_phys(vdev, pa);
}
static inline uint16_t vring_desc_next(VirtIODevice *vdev, hwaddr desc_pa,
int i)
{
hwaddr pa;
pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, next);
return virtio_lduw_phys(vdev, pa);
}
static inline uint16_t vring_avail_flags(VirtQueue *vq)
{
hwaddr pa;
pa = vq->vring.avail + offsetof(VRingAvail, flags);
return virtio_lduw_phys(vq->vdev, pa);
}
static inline uint16_t vring_avail_idx(VirtQueue *vq)
{
hwaddr pa;
pa = vq->vring.avail + offsetof(VRingAvail, idx);
return virtio_lduw_phys(vq->vdev, pa);
}
static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
{
hwaddr pa;
pa = vq->vring.avail + offsetof(VRingAvail, ring[i]);
return virtio_lduw_phys(vq->vdev, pa);
}
static inline uint16_t vring_used_event(VirtQueue *vq)
{
return vring_avail_ring(vq, vq->vring.num);
}
static inline void vring_used_ring_id(VirtQueue *vq, int i, uint32_t val)
{
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, ring[i].id);
virtio_stl_phys(vq->vdev, pa, val);
}
static inline void vring_used_ring_len(VirtQueue *vq, int i, uint32_t val)
{
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, ring[i].len);
virtio_stl_phys(vq->vdev, pa, val);
}
static uint16_t vring_used_idx(VirtQueue *vq)
{
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, idx);
return virtio_lduw_phys(vq->vdev, pa);
}
static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
{
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, idx);
virtio_stw_phys(vq->vdev, pa, val);
}
static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
{
VirtIODevice *vdev = vq->vdev;
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, flags);
virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) | mask);
}
static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
{
VirtIODevice *vdev = vq->vdev;
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, flags);
virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) & ~mask);
}
static inline void vring_avail_event(VirtQueue *vq, uint16_t val)
{
hwaddr pa;
if (!vq->notification) {
return;
}
pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]);
virtio_stw_phys(vq->vdev, pa, val);
}
void virtio_queue_set_notification(VirtQueue *vq, int enable)
{
vq->notification = enable;
if (vq->vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
vring_avail_event(vq, vring_avail_idx(vq));
} else if (enable) {
vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
} else {
vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
}
if (enable) {
/* Expose avail event/used flags before caller checks the avail idx. */
smp_mb();
}
}
int virtio_queue_ready(VirtQueue *vq)
{
return vq->vring.avail != 0;
}
int virtio_queue_empty(VirtQueue *vq)
{
return vring_avail_idx(vq) == vq->last_avail_idx;
}
void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len, unsigned int idx)
{
unsigned int offset;
int i;
trace_virtqueue_fill(vq, elem, len, idx);
offset = 0;
for (i = 0; i < elem->in_num; i++) {
size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
cpu_physical_memory_unmap(elem->in_sg[i].iov_base,
elem->in_sg[i].iov_len,
1, size);
offset += size;
}
for (i = 0; i < elem->out_num; i++)
cpu_physical_memory_unmap(elem->out_sg[i].iov_base,
elem->out_sg[i].iov_len,
0, elem->out_sg[i].iov_len);
idx = (idx + vring_used_idx(vq)) % vq->vring.num;
/* Get a pointer to the next entry in the used ring. */
vring_used_ring_id(vq, idx, elem->index);
vring_used_ring_len(vq, idx, len);
}
void virtqueue_flush(VirtQueue *vq, unsigned int count)
{
uint16_t old, new;
/* Make sure buffer is written before we update index. */
smp_wmb();
trace_virtqueue_flush(vq, count);
old = vring_used_idx(vq);
new = old + count;
vring_used_idx_set(vq, new);
vq->inuse -= count;
if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
vq->signalled_used_valid = false;
}
void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len)
{
virtqueue_fill(vq, elem, len, 0);
virtqueue_flush(vq, 1);
}
static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
{
uint16_t num_heads = vring_avail_idx(vq) - idx;
/* Check it isn't doing very strange things with descriptor numbers. */
if (num_heads > vq->vring.num) {
error_report("Guest moved used index from %u to %u",
idx, vring_avail_idx(vq));
exit(1);
}
/* On success, callers read a descriptor at vq->last_avail_idx.
* Make sure descriptor read does not bypass avail index read. */
if (num_heads) {
smp_rmb();
}
return num_heads;
}
static unsigned int virtqueue_get_head(VirtQueue *vq, unsigned int idx)
{
unsigned int head;
/* Grab the next descriptor number they're advertising, and increment
* the index we've seen. */
head = vring_avail_ring(vq, idx % vq->vring.num);
/* If their number is silly, that's a fatal mistake. */
if (head >= vq->vring.num) {
error_report("Guest says index %u is available", head);
exit(1);
}
return head;
}
static unsigned virtqueue_next_desc(VirtIODevice *vdev, hwaddr desc_pa,
unsigned int i, unsigned int max)
{
unsigned int next;
/* If this descriptor says it doesn't chain, we're done. */
if (!(vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_NEXT)) {
return max;
}
/* Check they're not leading us off end of descriptors. */
next = vring_desc_next(vdev, desc_pa, i);
/* Make sure compiler knows to grab that: we don't want it changing! */
smp_wmb();
if (next >= max) {
error_report("Desc next is %u", next);
exit(1);
}
return next;
}
void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
unsigned int *out_bytes,
unsigned max_in_bytes, unsigned max_out_bytes)
{
unsigned int idx;
unsigned int total_bufs, in_total, out_total;
idx = vq->last_avail_idx;
total_bufs = in_total = out_total = 0;
while (virtqueue_num_heads(vq, idx)) {
VirtIODevice *vdev = vq->vdev;
unsigned int max, num_bufs, indirect = 0;
hwaddr desc_pa;
int i;
max = vq->vring.num;
num_bufs = total_bufs;
i = virtqueue_get_head(vq, idx++);
desc_pa = vq->vring.desc;
if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_INDIRECT) {
if (vring_desc_len(vdev, desc_pa, i) % sizeof(VRingDesc)) {
error_report("Invalid size for indirect buffer table");
exit(1);
}
/* If we've got too many, that implies a descriptor loop. */
if (num_bufs >= max) {
error_report("Looped descriptor");
exit(1);
}
/* loop over the indirect descriptor table */
indirect = 1;
max = vring_desc_len(vdev, desc_pa, i) / sizeof(VRingDesc);
desc_pa = vring_desc_addr(vdev, desc_pa, i);
num_bufs = i = 0;
}
do {
/* If we've got too many, that implies a descriptor loop. */
if (++num_bufs > max) {
error_report("Looped descriptor");
exit(1);
}
if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_WRITE) {
in_total += vring_desc_len(vdev, desc_pa, i);
} else {
out_total += vring_desc_len(vdev, desc_pa, i);
}
if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
goto done;
}
} while ((i = virtqueue_next_desc(vdev, desc_pa, i, max)) != max);
if (!indirect)
total_bufs = num_bufs;
else
total_bufs++;
}
done:
if (in_bytes) {
*in_bytes = in_total;
}
if (out_bytes) {
*out_bytes = out_total;
}
}
int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
unsigned int out_bytes)
{
unsigned int in_total, out_total;
virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
return in_bytes <= in_total && out_bytes <= out_total;
}
void virtqueue_map_sg(struct iovec *sg, hwaddr *addr,
size_t num_sg, int is_write)
{
unsigned int i;
hwaddr len;
if (num_sg > VIRTQUEUE_MAX_SIZE) {
error_report("virtio: map attempt out of bounds: %zd > %d",
num_sg, VIRTQUEUE_MAX_SIZE);
exit(1);
}
for (i = 0; i < num_sg; i++) {
len = sg[i].iov_len;
sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write);
if (sg[i].iov_base == NULL || len != sg[i].iov_len) {
error_report("virtio: error trying to map MMIO memory");
exit(1);
}
}
}
int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
{
unsigned int i, head, max;
hwaddr desc_pa = vq->vring.desc;
VirtIODevice *vdev = vq->vdev;
if (!virtqueue_num_heads(vq, vq->last_avail_idx))
return 0;
/* When we start there are none of either input nor output. */
elem->out_num = elem->in_num = 0;
max = vq->vring.num;
i = head = virtqueue_get_head(vq, vq->last_avail_idx++);
if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
vring_avail_event(vq, vq->last_avail_idx);
}
if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_INDIRECT) {
if (vring_desc_len(vdev, desc_pa, i) % sizeof(VRingDesc)) {
error_report("Invalid size for indirect buffer table");
exit(1);
}
/* loop over the indirect descriptor table */
max = vring_desc_len(vdev, desc_pa, i) / sizeof(VRingDesc);
desc_pa = vring_desc_addr(vdev, desc_pa, i);
i = 0;
}
/* Collect all the descriptors */
do {
struct iovec *sg;
if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_WRITE) {
if (elem->in_num >= ARRAY_SIZE(elem->in_sg)) {
error_report("Too many write descriptors in indirect table");
exit(1);
}
elem->in_addr[elem->in_num] = vring_desc_addr(vdev, desc_pa, i);
sg = &elem->in_sg[elem->in_num++];
} else {
if (elem->out_num >= ARRAY_SIZE(elem->out_sg)) {
error_report("Too many read descriptors in indirect table");
exit(1);
}
elem->out_addr[elem->out_num] = vring_desc_addr(vdev, desc_pa, i);
sg = &elem->out_sg[elem->out_num++];
}
sg->iov_len = vring_desc_len(vdev, desc_pa, i);
/* If we've got too many, that implies a descriptor loop. */
if ((elem->in_num + elem->out_num) > max) {
error_report("Looped descriptor");
exit(1);
}
} while ((i = virtqueue_next_desc(vdev, desc_pa, i, max)) != max);
/* Now map what we have collected */
virtqueue_map_sg(elem->in_sg, elem->in_addr, elem->in_num, 1);
virtqueue_map_sg(elem->out_sg, elem->out_addr, elem->out_num, 0);
elem->index = head;
vq->inuse++;
trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
return elem->in_num + elem->out_num;
}
/* virtio device */
static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
{
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
if (k->notify) {
k->notify(qbus->parent, vector);
}
}
void virtio_update_irq(VirtIODevice *vdev)
{
virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
}
void virtio_set_status(VirtIODevice *vdev, uint8_t val)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
trace_virtio_set_status(vdev, val);
if (k->set_status) {
k->set_status(vdev, val);
}
vdev->status = val;
}
bool target_words_bigendian(void);
static enum virtio_device_endian virtio_default_endian(void)
{
if (target_words_bigendian()) {
return VIRTIO_DEVICE_ENDIAN_BIG;
} else {
return VIRTIO_DEVICE_ENDIAN_LITTLE;
}
}
static enum virtio_device_endian virtio_current_cpu_endian(void)
{
CPUClass *cc = CPU_GET_CLASS(current_cpu);
if (cc->virtio_is_big_endian(current_cpu)) {
return VIRTIO_DEVICE_ENDIAN_BIG;
} else {
return VIRTIO_DEVICE_ENDIAN_LITTLE;
}
}
void virtio_reset(void *opaque)
{
VirtIODevice *vdev = opaque;
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
int i;
virtio_set_status(vdev, 0);
if (current_cpu) {
/* Guest initiated reset */
vdev->device_endian = virtio_current_cpu_endian();
} else {
/* System reset */
vdev->device_endian = virtio_default_endian();
}
if (k->reset) {
k->reset(vdev);
}
vdev->guest_features = 0;
vdev->queue_sel = 0;
vdev->status = 0;
vdev->isr = 0;
vdev->config_vector = VIRTIO_NO_VECTOR;
virtio_notify_vector(vdev, vdev->config_vector);
for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
vdev->vq[i].vring.desc = 0;
vdev->vq[i].vring.avail = 0;
vdev->vq[i].vring.used = 0;
vdev->vq[i].last_avail_idx = 0;
vdev->vq[i].pa = 0;
vdev->vq[i].vector = VIRTIO_NO_VECTOR;
vdev->vq[i].signalled_used = 0;
vdev->vq[i].signalled_used_valid = false;
vdev->vq[i].notification = true;
}
}
uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
uint8_t val;
if (addr + sizeof(val) > vdev->config_len) {
return (uint32_t)-1;
}
k->get_config(vdev, vdev->config);
val = ldub_p(vdev->config + addr);
return val;
}
uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
uint16_t val;
if (addr + sizeof(val) > vdev->config_len) {
return (uint32_t)-1;
}
k->get_config(vdev, vdev->config);
val = lduw_p(vdev->config + addr);
return val;
}
uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
uint32_t val;
if (addr + sizeof(val) > vdev->config_len) {
return (uint32_t)-1;
}
k->get_config(vdev, vdev->config);
val = ldl_p(vdev->config + addr);
return val;
}
void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
uint8_t val = data;
if (addr + sizeof(val) > vdev->config_len) {
return;
}
stb_p(vdev->config + addr, val);
if (k->set_config) {
k->set_config(vdev, vdev->config);
}
}
void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
uint16_t val = data;
if (addr + sizeof(val) > vdev->config_len) {
return;
}
stw_p(vdev->config + addr, val);
if (k->set_config) {
k->set_config(vdev, vdev->config);
}
}
void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
uint32_t val = data;
if (addr + sizeof(val) > vdev->config_len) {
return;
}
stl_p(vdev->config + addr, val);
if (k->set_config) {
k->set_config(vdev, vdev->config);
}
}
void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
{
vdev->vq[n].pa = addr;
virtqueue_init(&vdev->vq[n]);
}
hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
{
return vdev->vq[n].pa;
}
void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
{
/* Don't allow guest to flip queue between existent and
* nonexistent states, or to set it to an invalid size.
*/
if (!!num != !!vdev->vq[n].vring.num ||
num > VIRTQUEUE_MAX_SIZE ||
num < 0) {
return;
}
vdev->vq[n].vring.num = num;
virtqueue_init(&vdev->vq[n]);
}
int virtio_queue_get_num(VirtIODevice *vdev, int n)
{
return vdev->vq[n].vring.num;
}
int virtio_queue_get_id(VirtQueue *vq)
{
VirtIODevice *vdev = vq->vdev;
assert(vq >= &vdev->vq[0] && vq < &vdev->vq[VIRTIO_PCI_QUEUE_MAX]);
return vq - &vdev->vq[0];
}
void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
{
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
/* Check that the transport told us it was going to do this
* (so a buggy transport will immediately assert rather than
* silently failing to migrate this state)
*/
assert(k->has_variable_vring_alignment);
vdev->vq[n].vring.align = align;
virtqueue_init(&vdev->vq[n]);
}
void virtio_queue_notify_vq(VirtQueue *vq)
{
if (vq->vring.desc) {
VirtIODevice *vdev = vq->vdev;
trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
vq->handle_output(vdev, vq);
}
}
void virtio_queue_notify(VirtIODevice *vdev, int n)
{
virtio_queue_notify_vq(&vdev->vq[n]);
}
uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
{
return n < VIRTIO_PCI_QUEUE_MAX ? vdev->vq[n].vector :
VIRTIO_NO_VECTOR;
}
void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
{
if (n < VIRTIO_PCI_QUEUE_MAX)
vdev->vq[n].vector = vector;
}
VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
void (*handle_output)(VirtIODevice *, VirtQueue *))
{
int i;
for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
if (vdev->vq[i].vring.num == 0)
break;
}
if (i == VIRTIO_PCI_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
abort();
vdev->vq[i].vring.num = queue_size;
vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
vdev->vq[i].handle_output = handle_output;
return &vdev->vq[i];
}
void virtio_del_queue(VirtIODevice *vdev, int n)
{
if (n < 0 || n >= VIRTIO_PCI_QUEUE_MAX) {
abort();
}
vdev->vq[n].vring.num = 0;
}
void virtio_irq(VirtQueue *vq)
{
trace_virtio_irq(vq);
vq->vdev->isr |= 0x01;
virtio_notify_vector(vq->vdev, vq->vector);
}
/* Assuming a given event_idx value from the other size, if
* we have just incremented index from old to new_idx,
* should we trigger an event? */
static inline int vring_need_event(uint16_t event, uint16_t new, uint16_t 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 respectively.
* Note also that req_event and req_prod in Xen start at 1,
* event indexes in virtio start at 0. */
return (uint16_t)(new - event - 1) < (uint16_t)(new - old);
}
static bool vring_notify(VirtIODevice *vdev, VirtQueue *vq)
{
uint16_t old, new;
bool v;
/* We need to expose used array entries before checking used event. */
smp_mb();
/* Always notify when queue is empty (when feature acknowledge) */
if (((vdev->guest_features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) &&
!vq->inuse && vring_avail_idx(vq) == vq->last_avail_idx)) {
return true;
}
if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
}
v = vq->signalled_used_valid;
vq->signalled_used_valid = true;
old = vq->signalled_used;
new = vq->signalled_used = vring_used_idx(vq);
return !v || vring_need_event(vring_used_event(vq), new, old);
}
void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
{
if (!vring_notify(vdev, vq)) {
return;
}
trace_virtio_notify(vdev, vq);
vdev->isr |= 0x01;
virtio_notify_vector(vdev, vq->vector);
}
void virtio_notify_config(VirtIODevice *vdev)
{
if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
return;
vdev->isr |= 0x03;
virtio_notify_vector(vdev, vdev->config_vector);
}
static bool virtio_device_endian_needed(void *opaque)
{
VirtIODevice *vdev = opaque;
assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
return vdev->device_endian != virtio_default_endian();
}
static const VMStateDescription vmstate_virtio_device_endian = {
.name = "virtio/device_endian",
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT8(device_endian, VirtIODevice),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription vmstate_virtio = {
.name = "virtio",
.version_id = 1,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.fields = (VMStateField[]) {
VMSTATE_END_OF_LIST()
},
.subsections = (VMStateSubsection[]) {
{
.vmsd = &vmstate_virtio_device_endian,
.needed = &virtio_device_endian_needed
},
{ 0 }
}
};
void virtio_save(VirtIODevice *vdev, QEMUFile *f)
{
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
int i;
if (k->save_config) {
k->save_config(qbus->parent, f);
}
qemu_put_8s(f, &vdev->status);
qemu_put_8s(f, &vdev->isr);
qemu_put_be16s(f, &vdev->queue_sel);
qemu_put_be32s(f, &vdev->guest_features);
qemu_put_be32(f, vdev->config_len);
qemu_put_buffer(f, vdev->config, vdev->config_len);
for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
if (vdev->vq[i].vring.num == 0)
break;
}
qemu_put_be32(f, i);
for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
if (vdev->vq[i].vring.num == 0)
break;
qemu_put_be32(f, vdev->vq[i].vring.num);
if (k->has_variable_vring_alignment) {
qemu_put_be32(f, vdev->vq[i].vring.align);
}
qemu_put_be64(f, vdev->vq[i].pa);
qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
if (k->save_queue) {
k->save_queue(qbus->parent, i, f);
}
}
if (vdc->save != NULL) {
vdc->save(vdev, f);
}
/* Subsections */
vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
}
int virtio_set_features(VirtIODevice *vdev, uint32_t val)
{
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *vbusk = VIRTIO_BUS_GET_CLASS(qbus);
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
uint32_t supported_features = vbusk->get_features(qbus->parent);
bool bad = (val & ~supported_features) != 0;
val &= supported_features;
if (k->set_features) {
k->set_features(vdev, val);
}
vdev->guest_features = val;
return bad ? -1 : 0;
}
int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
{
int i, ret;
int32_t config_len;
uint32_t num;
uint32_t features;
uint32_t supported_features;
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
/*
* We poison the endianness to ensure it does not get used before
* subsections have been loaded.
*/
vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
if (k->load_config) {
ret = k->load_config(qbus->parent, f);
if (ret)
return ret;
}
qemu_get_8s(f, &vdev->status);
qemu_get_8s(f, &vdev->isr);
qemu_get_be16s(f, &vdev->queue_sel);
if (vdev->queue_sel >= VIRTIO_PCI_QUEUE_MAX) {
return -1;
}
qemu_get_be32s(f, &features);
if (virtio_set_features(vdev, features) < 0) {
supported_features = k->get_features(qbus->parent);
error_report("Features 0x%x unsupported. Allowed features: 0x%x",
features, supported_features);
return -1;
}
config_len = qemu_get_be32(f);
/*
* There are cases where the incoming config can be bigger or smaller
* than what we have; so load what we have space for, and skip
* any excess that's in the stream.
*/
qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
while (config_len > vdev->config_len) {
qemu_get_byte(f);
config_len--;
}
num = qemu_get_be32(f);
if (num > VIRTIO_PCI_QUEUE_MAX) {
error_report("Invalid number of PCI queues: 0x%x", num);
return -1;
}
for (i = 0; i < num; i++) {
vdev->vq[i].vring.num = qemu_get_be32(f);
if (k->has_variable_vring_alignment) {
vdev->vq[i].vring.align = qemu_get_be32(f);
}
vdev->vq[i].pa = qemu_get_be64(f);
qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
vdev->vq[i].signalled_used_valid = false;
vdev->vq[i].notification = true;
if (vdev->vq[i].pa) {
virtqueue_init(&vdev->vq[i]);
} else if (vdev->vq[i].last_avail_idx) {
error_report("VQ %d address 0x0 "
"inconsistent with Host index 0x%x",
i, vdev->vq[i].last_avail_idx);
return -1;
}
if (k->load_queue) {
ret = k->load_queue(qbus->parent, i, f);
if (ret)
return ret;
}
}
virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
if (vdc->load != NULL) {
ret = vdc->load(vdev, f, version_id);
if (ret) {
return ret;
}
}
/* Subsections */
ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
if (ret) {
return ret;
}
if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
vdev->device_endian = virtio_default_endian();
}
for (i = 0; i < num; i++) {
if (vdev->vq[i].pa) {
uint16_t nheads;
nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
/* Check it isn't doing strange things with descriptor numbers. */
if (nheads > vdev->vq[i].vring.num) {
error_report("VQ %d size 0x%x Guest index 0x%x "
"inconsistent with Host index 0x%x: delta 0x%x",
i, vdev->vq[i].vring.num,
vring_avail_idx(&vdev->vq[i]),
vdev->vq[i].last_avail_idx, nheads);
return -1;
}
}
}
return 0;
}
void virtio_cleanup(VirtIODevice *vdev)
{
qemu_del_vm_change_state_handler(vdev->vmstate);
g_free(vdev->config);
g_free(vdev->vq);
}
static void virtio_vmstate_change(void *opaque, int running, RunState state)
{
VirtIODevice *vdev = opaque;
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
vdev->vm_running = running;
if (backend_run) {
virtio_set_status(vdev, vdev->status);
}
if (k->vmstate_change) {
k->vmstate_change(qbus->parent, backend_run);
}
if (!backend_run) {
virtio_set_status(vdev, vdev->status);
}
}
void virtio_instance_init_common(Object *proxy_obj, void *data,
size_t vdev_size, const char *vdev_name)
{
DeviceState *vdev = data;
object_initialize(vdev, vdev_size, vdev_name);
object_property_add_child(proxy_obj, "virtio-backend", OBJECT(vdev), NULL);
object_unref(OBJECT(vdev));
qdev_alias_all_properties(vdev, proxy_obj);
}
void virtio_init(VirtIODevice *vdev, const char *name,
uint16_t device_id, size_t config_size)
{
int i;
vdev->device_id = device_id;
vdev->status = 0;
vdev->isr = 0;
vdev->queue_sel = 0;
vdev->config_vector = VIRTIO_NO_VECTOR;
vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_PCI_QUEUE_MAX);
vdev->vm_running = runstate_is_running();
for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
vdev->vq[i].vector = VIRTIO_NO_VECTOR;
vdev->vq[i].vdev = vdev;
vdev->vq[i].queue_index = i;
}
vdev->name = name;
vdev->config_len = config_size;
if (vdev->config_len) {
vdev->config = g_malloc0(config_size);
} else {
vdev->config = NULL;
}
vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
vdev);
vdev->device_endian = virtio_default_endian();
}
hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
{
return vdev->vq[n].vring.desc;
}
hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
{
return vdev->vq[n].vring.avail;
}
hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
{
return vdev->vq[n].vring.used;
}
hwaddr virtio_queue_get_ring_addr(VirtIODevice *vdev, int n)
{
return vdev->vq[n].vring.desc;
}
hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
{
return sizeof(VRingDesc) * vdev->vq[n].vring.num;
}
hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
{
return offsetof(VRingAvail, ring) +
sizeof(uint64_t) * vdev->vq[n].vring.num;
}
hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
{
return offsetof(VRingUsed, ring) +
sizeof(VRingUsedElem) * vdev->vq[n].vring.num;
}
hwaddr virtio_queue_get_ring_size(VirtIODevice *vdev, int n)
{
return vdev->vq[n].vring.used - vdev->vq[n].vring.desc +
virtio_queue_get_used_size(vdev, n);
}
uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
{
return vdev->vq[n].last_avail_idx;
}
void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
{
vdev->vq[n].last_avail_idx = idx;
}
void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
{
vdev->vq[n].signalled_used_valid = false;
}
VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
{
return vdev->vq + n;
}
uint16_t virtio_get_queue_index(VirtQueue *vq)
{
return vq->queue_index;
}
static void virtio_queue_guest_notifier_read(EventNotifier *n)
{
VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
if (event_notifier_test_and_clear(n)) {
virtio_irq(vq);
}
}
void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
bool with_irqfd)
{
if (assign && !with_irqfd) {
event_notifier_set_handler(&vq->guest_notifier,
virtio_queue_guest_notifier_read);
} else {
event_notifier_set_handler(&vq->guest_notifier, NULL);
}
if (!assign) {
/* Test and clear notifier before closing it,
* in case poll callback didn't have time to run. */
virtio_queue_guest_notifier_read(&vq->guest_notifier);
}
}
EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
{
return &vq->guest_notifier;
}
static void virtio_queue_host_notifier_read(EventNotifier *n)
{
VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
if (event_notifier_test_and_clear(n)) {
virtio_queue_notify_vq(vq);
}
}
void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign,
bool set_handler)
{
if (assign && set_handler) {
event_notifier_set_handler(&vq->host_notifier,
virtio_queue_host_notifier_read);
} else {
event_notifier_set_handler(&vq->host_notifier, NULL);
}
if (!assign) {
/* Test and clear notifier before after disabling event,
* in case poll callback didn't have time to run. */
virtio_queue_host_notifier_read(&vq->host_notifier);
}
}
EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
{
return &vq->host_notifier;
}
void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
{
g_free(vdev->bus_name);
vdev->bus_name = g_strdup(bus_name);
}
static void virtio_device_realize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
Error *err = NULL;
if (vdc->realize != NULL) {
vdc->realize(dev, &err);
if (err != NULL) {
error_propagate(errp, err);
return;
}
}
virtio_bus_device_plugged(vdev);
}
static void virtio_device_unrealize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
Error *err = NULL;
virtio_bus_device_unplugged(vdev);
if (vdc->unrealize != NULL) {
vdc->unrealize(dev, &err);
if (err != NULL) {
error_propagate(errp, err);
return;
}
}
g_free(vdev->bus_name);
vdev->bus_name = NULL;
}
static void virtio_device_class_init(ObjectClass *klass, void *data)
{
/* Set the default value here. */
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = virtio_device_realize;
dc->unrealize = virtio_device_unrealize;
dc->bus_type = TYPE_VIRTIO_BUS;
}
static const TypeInfo virtio_device_info = {
.name = TYPE_VIRTIO_DEVICE,
.parent = TYPE_DEVICE,
.instance_size = sizeof(VirtIODevice),
.class_init = virtio_device_class_init,
.abstract = true,
.class_size = sizeof(VirtioDeviceClass),
};
static void virtio_register_types(void)
{
type_register_static(&virtio_device_info);
}
type_init(virtio_register_types)
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