virtio: Support transports which can specify the vring alignment
Support virtio transports which can specify the vring alignment (ie where the guest communicates this to the host) by providing a new virtio_queue_set_align() function. (The default alignment remains as before.) Transports which wish to make use of this must set the has_variable_vring_alignment field in their VirtioBusClass struct to true; they can then change the alignment via virtio_queue_set_align(). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1373977512-28932-5-git-send-email-peter.maydell@linaro.org
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@ -19,8 +19,11 @@
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#include "qemu/atomic.h"
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#include "qemu/atomic.h"
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#include "hw/virtio/virtio-bus.h"
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#include "hw/virtio/virtio-bus.h"
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/* The alignment to use between consumer and producer parts of vring.
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/*
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* x86 pagesize again. */
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* The alignment to use between consumer and producer parts of vring.
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* x86 pagesize again. This is the default, used by transports like PCI
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* which don't provide a means for the guest to tell the host the alignment.
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*/
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#define VIRTIO_PCI_VRING_ALIGN 4096
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#define VIRTIO_PCI_VRING_ALIGN 4096
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typedef struct VRingDesc
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typedef struct VRingDesc
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@ -54,6 +57,7 @@ typedef struct VRingUsed
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typedef struct VRing
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typedef struct VRing
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{
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{
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unsigned int num;
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unsigned int num;
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unsigned int align;
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hwaddr desc;
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hwaddr desc;
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hwaddr avail;
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hwaddr avail;
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hwaddr used;
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hwaddr used;
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@ -93,7 +97,7 @@ static void virtqueue_init(VirtQueue *vq)
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vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc);
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vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc);
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vq->vring.used = vring_align(vq->vring.avail +
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vq->vring.used = vring_align(vq->vring.avail +
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offsetof(VRingAvail, ring[vq->vring.num]),
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offsetof(VRingAvail, ring[vq->vring.num]),
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VIRTIO_PCI_VRING_ALIGN);
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vq->vring.align);
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}
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}
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static inline uint64_t vring_desc_addr(hwaddr desc_pa, int i)
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static inline uint64_t vring_desc_addr(hwaddr desc_pa, int i)
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@ -687,6 +691,21 @@ int virtio_queue_get_id(VirtQueue *vq)
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return vq - &vdev->vq[0];
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return vq - &vdev->vq[0];
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}
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}
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void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
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{
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BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
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/* Check that the transport told us it was going to do this
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* (so a buggy transport will immediately assert rather than
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* silently failing to migrate this state)
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*/
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assert(k->has_variable_vring_alignment);
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vdev->vq[n].vring.align = align;
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virtqueue_init(&vdev->vq[n]);
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}
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void virtio_queue_notify_vq(VirtQueue *vq)
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void virtio_queue_notify_vq(VirtQueue *vq)
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{
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{
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if (vq->vring.desc) {
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if (vq->vring.desc) {
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@ -727,6 +746,7 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
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abort();
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abort();
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vdev->vq[i].vring.num = queue_size;
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vdev->vq[i].vring.num = queue_size;
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vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
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vdev->vq[i].handle_output = handle_output;
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vdev->vq[i].handle_output = handle_output;
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return &vdev->vq[i];
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return &vdev->vq[i];
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@ -833,6 +853,9 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f)
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break;
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break;
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qemu_put_be32(f, vdev->vq[i].vring.num);
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qemu_put_be32(f, vdev->vq[i].vring.num);
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if (k->has_variable_vring_alignment) {
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qemu_put_be32(f, vdev->vq[i].vring.align);
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}
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qemu_put_be64(f, vdev->vq[i].pa);
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qemu_put_be64(f, vdev->vq[i].pa);
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qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
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qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
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if (k->save_queue) {
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if (k->save_queue) {
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@ -889,6 +912,9 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
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for (i = 0; i < num; i++) {
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for (i = 0; i < num; i++) {
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vdev->vq[i].vring.num = qemu_get_be32(f);
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vdev->vq[i].vring.num = qemu_get_be32(f);
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if (k->has_variable_vring_alignment) {
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vdev->vq[i].vring.align = qemu_get_be32(f);
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}
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vdev->vq[i].pa = qemu_get_be64(f);
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vdev->vq[i].pa = qemu_get_be64(f);
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qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
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qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
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vdev->vq[i].signalled_used_valid = false;
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vdev->vq[i].signalled_used_valid = false;
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@ -62,6 +62,12 @@ typedef struct VirtioBusClass {
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* This is called by virtio-bus just before the device is unplugged.
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* This is called by virtio-bus just before the device is unplugged.
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*/
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*/
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void (*device_unplug)(DeviceState *d);
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void (*device_unplug)(DeviceState *d);
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/*
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* Does the transport have variable vring alignment?
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* (ie can it ever call virtio_queue_set_align()?)
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* Note that changing this will break migration for this transport.
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*/
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bool has_variable_vring_alignment;
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} VirtioBusClass;
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} VirtioBusClass;
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struct VirtioBusState {
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struct VirtioBusState {
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@ -202,6 +202,7 @@ void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr);
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hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n);
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hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n);
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void virtio_queue_set_num(VirtIODevice *vdev, int n, int num);
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void virtio_queue_set_num(VirtIODevice *vdev, int n, int num);
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int virtio_queue_get_num(VirtIODevice *vdev, int n);
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int virtio_queue_get_num(VirtIODevice *vdev, int n);
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void virtio_queue_set_align(VirtIODevice *vdev, int n, int align);
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void virtio_queue_notify(VirtIODevice *vdev, int n);
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void virtio_queue_notify(VirtIODevice *vdev, int n);
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uint16_t virtio_queue_vector(VirtIODevice *vdev, int n);
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uint16_t virtio_queue_vector(VirtIODevice *vdev, int n);
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void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector);
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void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector);
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