Jason Wang
2021-Oct-19 09:24 UTC
[RFC PATCH v4 20/20] vdpa: Add custom IOTLB translations to SVQ
? 2021/10/1 ??3:06, Eugenio P?rez ??:> Use translations added in VhostIOVATree in SVQ. > > Now every element needs to store the previous address also, so VirtQueue > can consume the elements properly. This adds a little overhead per VQ > element, having to allocate more memory to stash them. As a possible > optimization, this allocation could be avoided if the descriptor is not > a chain but a single one, but this is left undone. > > TODO: iova range should be queried before, and add logic to fail when > GPA is outside of its range and memory listener or svq add it. > > Signed-off-by: Eugenio P?rez <eperezma at redhat.com> > --- > hw/virtio/vhost-shadow-virtqueue.h | 4 +- > hw/virtio/vhost-shadow-virtqueue.c | 130 ++++++++++++++++++++++++----- > hw/virtio/vhost-vdpa.c | 40 ++++++++- > hw/virtio/trace-events | 1 + > 4 files changed, 152 insertions(+), 23 deletions(-) > > diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h > index b7baa424a7..a0e6b5267a 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.h > +++ b/hw/virtio/vhost-shadow-virtqueue.h > @@ -11,6 +11,7 @@ > #define VHOST_SHADOW_VIRTQUEUE_H > > #include "hw/virtio/vhost.h" > +#include "hw/virtio/vhost-iova-tree.h" > > typedef struct VhostShadowVirtqueue VhostShadowVirtqueue; > > @@ -28,7 +29,8 @@ bool vhost_svq_start(struct vhost_dev *dev, unsigned idx, > void vhost_svq_stop(struct vhost_dev *dev, unsigned idx, > VhostShadowVirtqueue *svq); > > -VhostShadowVirtqueue *vhost_svq_new(struct vhost_dev *dev, int idx); > +VhostShadowVirtqueue *vhost_svq_new(struct vhost_dev *dev, int idx, > + VhostIOVATree *iova_map); > > void vhost_svq_free(VhostShadowVirtqueue *vq); > > diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c > index 2fd0bab75d..9db538547e 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.c > +++ b/hw/virtio/vhost-shadow-virtqueue.c > @@ -11,12 +11,19 @@ > #include "hw/virtio/vhost-shadow-virtqueue.h" > #include "hw/virtio/vhost.h" > #include "hw/virtio/virtio-access.h" > +#include "hw/virtio/vhost-iova-tree.h" > > #include "standard-headers/linux/vhost_types.h" > > #include "qemu/error-report.h" > #include "qemu/main-loop.h" > > +typedef struct SVQElement { > + VirtQueueElement elem; > + void **in_sg_stash; > + void **out_sg_stash; > +} SVQElement; > + > /* Shadow virtqueue to relay notifications */ > typedef struct VhostShadowVirtqueue { > /* Shadow vring */ > @@ -46,8 +53,11 @@ typedef struct VhostShadowVirtqueue { > /* Virtio device */ > VirtIODevice *vdev; > > + /* IOVA mapping if used */ > + VhostIOVATree *iova_map; > + > /* Map for returning guest's descriptors */ > - VirtQueueElement **ring_id_maps; > + SVQElement **ring_id_maps; > > /* Next head to expose to device */ > uint16_t avail_idx_shadow; > @@ -79,13 +89,6 @@ bool vhost_svq_valid_device_features(uint64_t *dev_features) > continue; > > case VIRTIO_F_ACCESS_PLATFORM: > - /* SVQ needs this feature disabled. Can't continue */ > - if (*dev_features & BIT_ULL(b)) { > - clear_bit(b, dev_features); > - r = false; > - } > - break; > - > case VIRTIO_F_VERSION_1: > /* SVQ needs this feature, so can't continue */ > if (!(*dev_features & BIT_ULL(b))) { > @@ -126,6 +129,64 @@ static void vhost_svq_set_notification(VhostShadowVirtqueue *svq, bool enable) > } > } > > +static void vhost_svq_stash_addr(void ***stash, const struct iovec *iov, > + size_t num) > +{ > + size_t i; > + > + if (num == 0) { > + return; > + } > + > + *stash = g_new(void *, num); > + for (i = 0; i < num; ++i) { > + (*stash)[i] = iov[i].iov_base; > + } > +} > + > +static void vhost_svq_unstash_addr(void **stash, struct iovec *iov, size_t num) > +{ > + size_t i; > + > + if (num == 0) { > + return; > + } > + > + for (i = 0; i < num; ++i) { > + iov[i].iov_base = stash[i]; > + } > + g_free(stash); > +} > + > +static void vhost_svq_translate_addr(const VhostShadowVirtqueue *svq, > + struct iovec *iovec, size_t num) > +{ > + size_t i; > + > + for (i = 0; i < num; ++i) { > + VhostDMAMap needle = { > + .translated_addr = iovec[i].iov_base, > + .size = iovec[i].iov_len, > + }; > + size_t off; > + > + const VhostDMAMap *map = vhost_iova_tree_find_iova(svq->iova_map, > + &needle);Is it possible that we end up with more than one maps here?> + /* > + * Map cannot be NULL since iova map contains all guest space and > + * qemu already has a physical address mapped > + */ > + assert(map); > + > + /* > + * Map->iova chunk size is ignored. What to do if descriptor > + * (addr, size) does not fit is delegated to the device. > + */ > + off = needle.translated_addr - map->translated_addr; > + iovec[i].iov_base = (void *)(map->iova + off); > + } > +} > + > static void vhost_vring_write_descs(VhostShadowVirtqueue *svq, > const struct iovec *iovec, > size_t num, bool more_descs, bool write) > @@ -156,8 +217,9 @@ static void vhost_vring_write_descs(VhostShadowVirtqueue *svq, > } > > static unsigned vhost_svq_add_split(VhostShadowVirtqueue *svq, > - VirtQueueElement *elem) > + SVQElement *svq_elem) > { > + VirtQueueElement *elem = &svq_elem->elem; > int head; > unsigned avail_idx; > vring_avail_t *avail = svq->vring.avail; > @@ -167,6 +229,12 @@ static unsigned vhost_svq_add_split(VhostShadowVirtqueue *svq, > /* We need some descriptors here */ > assert(elem->out_num || elem->in_num); > > + vhost_svq_stash_addr(&svq_elem->in_sg_stash, elem->in_sg, elem->in_num); > + vhost_svq_stash_addr(&svq_elem->out_sg_stash, elem->out_sg, elem->out_num);I wonder if we can solve the trick like stash and unstash with a dedicated sgs in svq_elem, instead of reusing the elem. Thanks> + > + vhost_svq_translate_addr(svq, elem->in_sg, elem->in_num); > + vhost_svq_translate_addr(svq, elem->out_sg, elem->out_num); > + > vhost_vring_write_descs(svq, elem->out_sg, elem->out_num, > elem->in_num > 0, false); > vhost_vring_write_descs(svq, elem->in_sg, elem->in_num, false, true); > @@ -187,7 +255,7 @@ static unsigned vhost_svq_add_split(VhostShadowVirtqueue *svq, > > } > > -static void vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem) > +static void vhost_svq_add(VhostShadowVirtqueue *svq, SVQElement *elem) > { > unsigned qemu_head = vhost_svq_add_split(svq, elem); > > @@ -221,7 +289,7 @@ static void vhost_handle_guest_kick(EventNotifier *n) > } > > while (true) { > - VirtQueueElement *elem = virtqueue_pop(svq->vq, sizeof(*elem)); > + SVQElement *elem = virtqueue_pop(svq->vq, sizeof(*elem)); > if (!elem) { > break; > } > @@ -247,7 +315,7 @@ static bool vhost_svq_more_used(VhostShadowVirtqueue *svq) > return svq->used_idx != svq->shadow_used_idx; > } > > -static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq) > +static SVQElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq) > { > vring_desc_t *descs = svq->vring.desc; > const vring_used_t *used = svq->vring.used; > @@ -279,7 +347,7 @@ static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq) > descs[used_elem.id].next = svq->free_head; > svq->free_head = used_elem.id; > > - svq->ring_id_maps[used_elem.id]->len = used_elem.len; > + svq->ring_id_maps[used_elem.id]->elem.len = used_elem.len; > return g_steal_pointer(&svq->ring_id_maps[used_elem.id]); > } > > @@ -296,12 +364,19 @@ static void vhost_svq_handle_call_no_test(EventNotifier *n) > > vhost_svq_set_notification(svq, false); > while (true) { > - g_autofree VirtQueueElement *elem = vhost_svq_get_buf(svq); > - if (!elem) { > + g_autofree SVQElement *svq_elem = vhost_svq_get_buf(svq); > + VirtQueueElement *elem; > + if (!svq_elem) { > break; > } > > assert(i < svq->vring.num); > + elem = &svq_elem->elem; > + > + vhost_svq_unstash_addr(svq_elem->in_sg_stash, elem->in_sg, > + elem->in_num); > + vhost_svq_unstash_addr(svq_elem->out_sg_stash, elem->out_sg, > + elem->out_num); > virtqueue_fill(vq, elem, elem->len, i++); > } > > @@ -451,14 +526,24 @@ void vhost_svq_stop(struct vhost_dev *dev, unsigned idx, > event_notifier_set_handler(&svq->host_notifier, NULL); > > for (i = 0; i < svq->vring.num; ++i) { > - g_autofree VirtQueueElement *elem = svq->ring_id_maps[i]; > + g_autofree SVQElement *svq_elem = svq->ring_id_maps[i]; > + VirtQueueElement *elem; > + > + if (!svq_elem) { > + continue; > + } > + > + elem = &svq_elem->elem; > + vhost_svq_unstash_addr(svq_elem->in_sg_stash, elem->in_sg, > + elem->in_num); > + vhost_svq_unstash_addr(svq_elem->out_sg_stash, elem->out_sg, > + elem->out_num); > + > /* > * Although the doc says we must unpop in order, it's ok to unpop > * everything. > */ > - if (elem) { > - virtqueue_unpop(svq->vq, elem, elem->len); > - } > + virtqueue_unpop(svq->vq, elem, elem->len); > } > } > > @@ -466,7 +551,8 @@ void vhost_svq_stop(struct vhost_dev *dev, unsigned idx, > * Creates vhost shadow virtqueue, and instruct vhost device to use the shadow > * methods and file descriptors. > */ > -VhostShadowVirtqueue *vhost_svq_new(struct vhost_dev *dev, int idx) > +VhostShadowVirtqueue *vhost_svq_new(struct vhost_dev *dev, int idx, > + VhostIOVATree *iova_map) > { > int vq_idx = dev->vq_index + idx; > unsigned num = virtio_queue_get_num(dev->vdev, vq_idx); > @@ -500,11 +586,13 @@ VhostShadowVirtqueue *vhost_svq_new(struct vhost_dev *dev, int idx) > memset(svq->vring.desc, 0, driver_size); > svq->vring.used = qemu_memalign(qemu_real_host_page_size, device_size); > memset(svq->vring.used, 0, device_size); > + svq->iova_map = iova_map; > + > for (i = 0; i < num - 1; i++) { > svq->vring.desc[i].next = cpu_to_le16(i + 1); > } > > - svq->ring_id_maps = g_new0(VirtQueueElement *, num); > + svq->ring_id_maps = g_new0(SVQElement *, num); > event_notifier_set_handler(&svq->call_notifier, > vhost_svq_handle_call); > return g_steal_pointer(&svq); > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c > index a9c680b487..f5a12fee9d 100644 > --- a/hw/virtio/vhost-vdpa.c > +++ b/hw/virtio/vhost-vdpa.c > @@ -176,6 +176,18 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener, > vaddr, section->readonly); > > llsize = int128_sub(llend, int128_make64(iova)); > + if (v->shadow_vqs_enabled) { > + VhostDMAMap mem_region = { > + .translated_addr = vaddr, > + .size = int128_get64(llsize) - 1, > + .perm = IOMMU_ACCESS_FLAG(true, section->readonly), > + }; > + > + int r = vhost_iova_tree_alloc(v->iova_map, &mem_region); > + assert(r == VHOST_DMA_MAP_OK); > + > + iova = mem_region.iova; > + } > > ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize), > vaddr, section->readonly); > @@ -754,6 +766,23 @@ static bool vhost_vdpa_force_iommu(struct vhost_dev *dev) > return true; > } > > +static int vhost_vdpa_get_iova_range(struct vhost_dev *dev, > + hwaddr *first, hwaddr *last) > +{ > + int ret; > + struct vhost_vdpa_iova_range range; > + > + ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_IOVA_RANGE, &range); > + if (ret != 0) { > + return ret; > + } > + > + *first = range.first; > + *last = range.last; > + trace_vhost_vdpa_get_iova_range(dev, *first, *last); > + return ret; > +} > + > /** > * Maps QEMU vaddr memory to device in a suitable way for shadow virtqueue: > * - It always reference qemu memory address, not guest's memory. > @@ -881,6 +910,7 @@ static bool vhost_vdpa_svq_start_vq(struct vhost_dev *dev, unsigned idx) > static unsigned vhost_vdpa_enable_svq(struct vhost_vdpa *v, bool enable) > { > struct vhost_dev *hdev = v->dev; > + hwaddr iova_first, iova_last; > unsigned n; > int r; > > @@ -894,7 +924,7 @@ static unsigned vhost_vdpa_enable_svq(struct vhost_vdpa *v, bool enable) > /* Allocate resources */ > assert(v->shadow_vqs->len == 0); > for (n = 0; n < hdev->nvqs; ++n) { > - VhostShadowVirtqueue *svq = vhost_svq_new(hdev, n); > + VhostShadowVirtqueue *svq = vhost_svq_new(hdev, n, v->iova_map); > if (unlikely(!svq)) { > g_ptr_array_set_size(v->shadow_vqs, 0); > return 0; > @@ -903,6 +933,8 @@ static unsigned vhost_vdpa_enable_svq(struct vhost_vdpa *v, bool enable) > } > } > > + r = vhost_vdpa_get_iova_range(hdev, &iova_first, &iova_last); > + assert(r == 0); > r = vhost_vdpa_vring_pause(hdev); > assert(r == 0); > > @@ -913,6 +945,12 @@ static unsigned vhost_vdpa_enable_svq(struct vhost_vdpa *v, bool enable) > } > } > > + memory_listener_unregister(&v->listener); > + if (vhost_vdpa_dma_unmap(v, iova_first, > + (iova_last - iova_first) & TARGET_PAGE_MASK)) { > + error_report("Fail to invalidate device iotlb"); > + } > + > /* Reset device so it can be configured */ > r = vhost_vdpa_dev_start(hdev, false); > assert(r == 0); > diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events > index 8ed19e9d0c..650e521e35 100644 > --- a/hw/virtio/trace-events > +++ b/hw/virtio/trace-events > @@ -52,6 +52,7 @@ vhost_vdpa_set_vring_call(void *dev, unsigned int index, int fd) "dev: %p index: > vhost_vdpa_get_features(void *dev, uint64_t features) "dev: %p features: 0x%"PRIx64 > vhost_vdpa_set_owner(void *dev) "dev: %p" > vhost_vdpa_vq_get_addr(void *dev, void *vq, uint64_t desc_user_addr, uint64_t avail_user_addr, uint64_t used_user_addr) "dev: %p vq: %p desc_user_addr: 0x%"PRIx64" avail_user_addr: 0x%"PRIx64" used_user_addr: 0x%"PRIx64 > +vhost_vdpa_get_iova_range(void *dev, uint64_t first, uint64_t last) "dev: %p first: 0x%"PRIx64" last: 0x%"PRIx64 > > # virtio.c > virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, unsigned out_num) "elem %p size %zd in_num %u out_num %u"