On Wed, 23 Sep 2020 04:54:15 +0530
Kirti Wankhede <kwankh...@nvidia.com> wrote:
> Create mapped iova list when vIOMMU is enabled. For each mapped iova
> save translated address. Add node to list on MAP and remove node from
> list on UNMAP.
> This list is used to track dirty pages during migration.
>
> Signed-off-by: Kirti Wankhede <kwankh...@nvidia.com>
> ---
> hw/vfio/common.c | 58
> ++++++++++++++++++++++++++++++++++++++-----
> include/hw/vfio/vfio-common.h | 8 ++++++
> 2 files changed, 60 insertions(+), 6 deletions(-)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index d4959c036dd1..dc56cded2d95 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -407,8 +407,8 @@ static bool
> vfio_listener_skipped_section(MemoryRegionSection *section)
> }
>
> /* Called with rcu_read_lock held. */
> -static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
> - bool *read_only)
> +static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
> + ram_addr_t *ram_addr, bool *read_only)
> {
> MemoryRegion *mr;
> hwaddr xlat;
> @@ -439,8 +439,17 @@ static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void
> **vaddr,
> return false;
> }
>
> - *vaddr = memory_region_get_ram_ptr(mr) + xlat;
> - *read_only = !writable || mr->readonly;
> + if (vaddr) {
> + *vaddr = memory_region_get_ram_ptr(mr) + xlat;
> + }
> +
> + if (ram_addr) {
> + *ram_addr = memory_region_get_ram_addr(mr) + xlat;
> + }
> +
> + if (read_only) {
> + *read_only = !writable || mr->readonly;
> + }
>
> return true;
> }
> @@ -450,7 +459,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n,
> IOMMUTLBEntry *iotlb)
> VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
> VFIOContainer *container = giommu->container;
> hwaddr iova = iotlb->iova + giommu->iommu_offset;
> - bool read_only;
> void *vaddr;
> int ret;
>
> @@ -466,7 +474,10 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n,
> IOMMUTLBEntry *iotlb)
> rcu_read_lock();
>
> if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> - if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> + ram_addr_t ram_addr;
> + bool read_only;
> +
> + if (!vfio_get_xlat_addr(iotlb, &vaddr, &ram_addr, &read_only)) {
> goto out;
> }
> /*
> @@ -484,8 +495,28 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n,
> IOMMUTLBEntry *iotlb)
> "0x%"HWADDR_PRIx", %p) = %d (%m)",
> container, iova,
> iotlb->addr_mask + 1, vaddr, ret);
> + } else {
> + VFIOIovaRange *iova_range;
> +
> + iova_range = g_malloc0(sizeof(*iova_range));
> + iova_range->iova = iova;
> + iova_range->size = iotlb->addr_mask + 1;
> + iova_range->ram_addr = ram_addr;
> +
> + QLIST_INSERT_HEAD(&giommu->iova_list, iova_range, next);
> }
> } else {
> + VFIOIovaRange *iova_range, *tmp;
> +
> + QLIST_FOREACH_SAFE(iova_range, &giommu->iova_list, next, tmp) {
> + if (iova_range->iova >= iova &&
> + iova_range->iova + iova_range->size <= iova +
> + iotlb->addr_mask + 1)
> {
> + QLIST_REMOVE(iova_range, next);
> + g_free(iova_range);
> + }
> + }
> +
This is some pretty serious overhead... can't we trigger a replay when
migration is enabled to build this information then? We're looking at
potentially thousands of entries, so a list is probably also not a good
choice. I don't think it's acceptable to incur this even when not
migrating (ie. the vast majority of the time). Thanks,
Alex
> ret = vfio_dma_unmap(container, iova, iotlb->addr_mask + 1);
> if (ret) {
> error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
> @@ -642,6 +673,7 @@ static void vfio_listener_region_add(MemoryListener
> *listener,
> g_free(giommu);
> goto fail;
> }
> + QLIST_INIT(&giommu->iova_list);
> QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
> memory_region_iommu_replay(giommu->iommu, &giommu->n);
>
> @@ -740,6 +772,13 @@ static void vfio_listener_region_del(MemoryListener
> *listener,
> QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
> if (MEMORY_REGION(giommu->iommu) == section->mr &&
> giommu->n.start == section->offset_within_region) {
> + VFIOIovaRange *iova_range, *tmp;
> +
> + QLIST_FOREACH_SAFE(iova_range, &giommu->iova_list, next,
> tmp) {
> + QLIST_REMOVE(iova_range, next);
> + g_free(iova_range);
> + }
> +
> memory_region_unregister_iommu_notifier(section->mr,
> &giommu->n);
> QLIST_REMOVE(giommu, giommu_next);
> @@ -1541,6 +1580,13 @@ static void vfio_disconnect_container(VFIOGroup *group)
> QLIST_REMOVE(container, next);
>
> QLIST_FOREACH_SAFE(giommu, &container->giommu_list, giommu_next,
> tmp) {
> + VFIOIovaRange *iova_range, *itmp;
> +
> + QLIST_FOREACH_SAFE(iova_range, &giommu->iova_list, next, itmp) {
> + QLIST_REMOVE(iova_range, next);
> + g_free(iova_range);
> + }
> +
> memory_region_unregister_iommu_notifier(
> MEMORY_REGION(giommu->iommu), &giommu->n);
> QLIST_REMOVE(giommu, giommu_next);
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 0a1651eda2d0..aa7524fe2cc5 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -89,11 +89,19 @@ typedef struct VFIOContainer {
> QLIST_ENTRY(VFIOContainer) next;
> } VFIOContainer;
>
> +typedef struct VFIOIovaRange {
> + hwaddr iova;
> + size_t size;
> + ram_addr_t ram_addr;
> + QLIST_ENTRY(VFIOIovaRange) next;
> +} VFIOIovaRange;
> +
> typedef struct VFIOGuestIOMMU {
> VFIOContainer *container;
> IOMMUMemoryRegion *iommu;
> hwaddr iommu_offset;
> IOMMUNotifier n;
> + QLIST_HEAD(, VFIOIovaRange) iova_list;
> QLIST_ENTRY(VFIOGuestIOMMU) giommu_next;
> } VFIOGuestIOMMU;
>
