Re: [PATCH v9 1/2] vfio: move implement of vfio_get_xlat_addr() to memory.c

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Oct 31, 2022 at 11:10:19AM +0800, Cindy Lu wrote:
> - Move the implement vfio_get_xlat_addr to softmmu/memory.c, and
>   change the name to memory_get_xlat_addr(). So we can use this
>   function on other devices, such as vDPA device.
> - Add a new function vfio_get_xlat_addr in vfio/common.c, and it will check
>   whether the memory is backed by a discard manager. then device can
>   have its own warning.
> 
> Signed-off-by: Cindy Lu <lulu@redhat.com>

Could you rebase on top of my tree (config interrupt support conflicts).

> ---
>  hw/vfio/common.c      | 66 +++------------------------------------
>  include/exec/memory.h |  4 +++
>  softmmu/memory.c      | 72 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 81 insertions(+), 61 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index ace9562a9b..6bc02b32c8 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -578,45 +578,11 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
>  static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
>                                 ram_addr_t *ram_addr, bool *read_only)
>  {
> -    MemoryRegion *mr;
> -    hwaddr xlat;
> -    hwaddr len = iotlb->addr_mask + 1;
> -    bool writable = iotlb->perm & IOMMU_WO;
> -
> -    /*
> -     * The IOMMU TLB entry we have just covers translation through
> -     * this IOMMU to its immediate target.  We need to translate
> -     * it the rest of the way through to memory.
> -     */
> -    mr = address_space_translate(&address_space_memory,
> -                                 iotlb->translated_addr,
> -                                 &xlat, &len, writable,
> -                                 MEMTXATTRS_UNSPECIFIED);
> -    if (!memory_region_is_ram(mr)) {
> -        error_report("iommu map to non memory area %"HWADDR_PRIx"",
> -                     xlat);
> -        return false;
> -    } else if (memory_region_has_ram_discard_manager(mr)) {
> -        RamDiscardManager *rdm = memory_region_get_ram_discard_manager(mr);
> -        MemoryRegionSection tmp = {
> -            .mr = mr,
> -            .offset_within_region = xlat,
> -            .size = int128_make64(len),
> -        };
> -
> -        /*
> -         * Malicious VMs can map memory into the IOMMU, which is expected
> -         * to remain discarded. vfio will pin all pages, populating memory.
> -         * Disallow that. vmstate priorities make sure any RamDiscardManager
> -         * were already restored before IOMMUs are restored.
> -         */
> -        if (!ram_discard_manager_is_populated(rdm, &tmp)) {
> -            error_report("iommu map to discarded memory (e.g., unplugged via"
> -                         " virtio-mem): %"HWADDR_PRIx"",
> -                         iotlb->translated_addr);
> -            return false;
> -        }
> +    bool ret, mr_has_discard_manager;
>  
> +    ret = memory_get_xlat_addr(iotlb, vaddr, ram_addr, read_only,
> +                               &mr_has_discard_manager);
> +    if (ret && mr_has_discard_manager) {
>          /*
>           * Malicious VMs might trigger discarding of IOMMU-mapped memory. The
>           * pages will remain pinned inside vfio until unmapped, resulting in a
> @@ -635,29 +601,7 @@ static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
>                           " intended via an IOMMU. It's possible to mitigate "
>                           " by setting/adjusting RLIMIT_MEMLOCK.");
>      }
> -
> -    /*
> -     * Translation truncates length to the IOMMU page size,
> -     * check that it did not truncate too much.
> -     */
> -    if (len & iotlb->addr_mask) {
> -        error_report("iommu has granularity incompatible with target AS");
> -        return false;
> -    }
> -
> -    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;
> +    return ret;
>  }
>  
>  static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index bfb1de8eea..d1e79c39dc 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -713,6 +713,10 @@ void ram_discard_manager_register_listener(RamDiscardManager *rdm,
>  void ram_discard_manager_unregister_listener(RamDiscardManager *rdm,
>                                               RamDiscardListener *rdl);
>  
> +bool memory_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
> +                          ram_addr_t *ram_addr, bool *read_only,
> +                          bool *mr_has_discard_manager);
> +
>  typedef struct CoalescedMemoryRange CoalescedMemoryRange;
>  typedef struct MemoryRegionIoeventfd MemoryRegionIoeventfd;
>  
> diff --git a/softmmu/memory.c b/softmmu/memory.c
> index 7ba2048836..bc0be3f62c 100644
> --- a/softmmu/memory.c
> +++ b/softmmu/memory.c
> @@ -33,6 +33,7 @@
>  #include "qemu/accel.h"
>  #include "hw/boards.h"
>  #include "migration/vmstate.h"
> +#include "exec/address-spaces.h"
>  
>  //#define DEBUG_UNASSIGNED
>  
> @@ -2121,6 +2122,77 @@ void ram_discard_manager_unregister_listener(RamDiscardManager *rdm,
>      rdmc->unregister_listener(rdm, rdl);
>  }
>  
> +/* Called with rcu_read_lock held.  */
> +bool memory_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
> +                          ram_addr_t *ram_addr, bool *read_only,
> +                          bool *mr_has_discard_manager)
> +{
> +    MemoryRegion *mr;
> +    hwaddr xlat;
> +    hwaddr len = iotlb->addr_mask + 1;
> +    bool writable = iotlb->perm & IOMMU_WO;
> +
> +    if (mr_has_discard_manager) {
> +        *mr_has_discard_manager = false;
> +    }
> +    /*
> +     * The IOMMU TLB entry we have just covers translation through
> +     * this IOMMU to its immediate target.  We need to translate
> +     * it the rest of the way through to memory.
> +     */
> +    mr = address_space_translate(&address_space_memory, iotlb->translated_addr,
> +                                 &xlat, &len, writable, MEMTXATTRS_UNSPECIFIED);
> +    if (!memory_region_is_ram(mr)) {
> +        error_report("iommu map to non memory area %" HWADDR_PRIx "", xlat);
> +        return false;
> +    } else if (memory_region_has_ram_discard_manager(mr)) {
> +        RamDiscardManager *rdm = memory_region_get_ram_discard_manager(mr);
> +        MemoryRegionSection tmp = {
> +            .mr = mr,
> +            .offset_within_region = xlat,
> +            .size = int128_make64(len),
> +        };
> +        if (mr_has_discard_manager) {
> +            *mr_has_discard_manager = true;
> +        }
> +        /*
> +         * Malicious VMs can map memory into the IOMMU, which is expected
> +         * to remain discarded. vfio will pin all pages, populating memory.
> +         * Disallow that. vmstate priorities make sure any RamDiscardManager
> +         * were already restored before IOMMUs are restored.
> +         */
> +        if (!ram_discard_manager_is_populated(rdm, &tmp)) {
> +            error_report("iommu map to discarded memory (e.g., unplugged via"
> +                         " virtio-mem): %" HWADDR_PRIx "",
> +                         iotlb->translated_addr);
> +            return false;
> +        }
> +    }
> +
> +    /*
> +     * Translation truncates length to the IOMMU page size,
> +     * check that it did not truncate too much.
> +     */
> +    if (len & iotlb->addr_mask) {
> +        error_report("iommu has granularity incompatible with target AS");
> +        return false;
> +    }
> +
> +    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;
> +}
> +
>  void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client)
>  {
>      uint8_t mask = 1 << client;
> -- 
> 2.34.3

On Mon, Oct 31, 2022 at 11:10:20AM +0800, Cindy Lu wrote:
> Add support for vIOMMU. add the new function to deal with iommu MR.
> - during iommu_region_add register a specific IOMMU notifier,
>  and store all notifiers in a list.
> - during iommu_region_del, compare and delete the IOMMU notifier from the list
> 
> Verified in vp_vdpa and vdpa_sim_net driver
> 
> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---
>  hw/virtio/vhost-vdpa.c         | 123 ++++++++++++++++++++++++++++++---
>  include/hw/virtio/vhost-vdpa.h |  10 +++
>  2 files changed, 122 insertions(+), 11 deletions(-)
> 
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 3ff9ce3501..dcfaaccfa9 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -26,6 +26,7 @@
>  #include "cpu.h"
>  #include "trace.h"
>  #include "qapi/error.h"
> +#include "hw/virtio/virtio-access.h"
>  
>  /*
>   * Return one past the end of the end of section. Be careful with uint64_t
> @@ -44,7 +45,6 @@ static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection *section,
>                                                  uint64_t iova_min,
>                                                  uint64_t iova_max)
>  {
> -    Int128 llend;
>  
>      if ((!memory_region_is_ram(section->mr) &&
>           !memory_region_is_iommu(section->mr)) ||
> @@ -61,14 +61,6 @@ static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection *section,
>          return true;
>      }
>  
> -    llend = vhost_vdpa_section_end(section);
> -    if (int128_gt(llend, int128_make64(iova_max))) {
> -        error_report("RAM section out of device range (max=0x%" PRIx64
> -                     ", end addr=0x%" PRIx64 ")",
> -                     iova_max, int128_get64(llend));
> -        return true;
> -    }
> -
>      return false;
>  }
>  
> @@ -173,6 +165,106 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener)
>      v->iotlb_batch_begin_sent = false;
>  }
>  
> +static void vhost_vdpa_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> +{
> +    struct vdpa_iommu *iommu = container_of(n, struct vdpa_iommu, n);
> +
> +    hwaddr iova = iotlb->iova + iommu->iommu_offset;
> +    struct vhost_vdpa *v = iommu->dev;
> +    void *vaddr;
> +    int ret;
> +
> +    if (iotlb->target_as != &address_space_memory) {
> +        error_report("Wrong target AS \"%s\", only system memory is allowed",
> +                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> +        return;
> +    }
> +    RCU_READ_LOCK_GUARD();
> +    vhost_vdpa_iotlb_batch_begin_once(v);
> +
> +    if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> +        bool read_only;
> +
> +        if (!memory_get_xlat_addr(iotlb, &vaddr, NULL, &read_only, NULL)) {
> +            return;
> +        }
> +        ret =
> +            vhost_vdpa_dma_map(v, iova, iotlb->addr_mask + 1, vaddr, read_only);
> +        if (ret) {
> +            error_report("vhost_vdpa_dma_map(%p, 0x%" HWADDR_PRIx ", "
> +                         "0x%" HWADDR_PRIx ", %p) = %d (%m)",
> +                         v, iova, iotlb->addr_mask + 1, vaddr, ret);
> +        }
> +    } else {
> +        ret = vhost_vdpa_dma_unmap(v, iova, iotlb->addr_mask + 1);
> +        if (ret) {
> +            error_report("vhost_vdpa_dma_unmap(%p, 0x%" HWADDR_PRIx ", "
> +                         "0x%" HWADDR_PRIx ") = %d (%m)",
> +                         v, iova, iotlb->addr_mask + 1, ret);
> +        }
> +    }
> +}
> +
> +static void vhost_vdpa_iommu_region_add(MemoryListener *listener,
> +                                        MemoryRegionSection *section)
> +{
> +    struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener);
> +
> +    struct vdpa_iommu *iommu;
> +    Int128 end;
> +    int iommu_idx;
> +    IOMMUMemoryRegion *iommu_mr;
> +    int ret;
> +
> +    iommu_mr = IOMMU_MEMORY_REGION(section->mr);
> +
> +    iommu = g_malloc0(sizeof(*iommu));
> +    end =  int128_add(int128_make64(section->offset_within_region),
> +            section->size);
> +    end = int128_sub(end, int128_one());
> +    iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
> +            MEMTXATTRS_UNSPECIFIED);
> +
> +    iommu->iommu_mr = iommu_mr;
> +
> +    iommu_notifier_init(
> +        &iommu->n, vhost_vdpa_iommu_map_notify, IOMMU_NOTIFIER_IOTLB_EVENTS,
> +        section->offset_within_region, int128_get64(end), iommu_idx);
> +    iommu->iommu_offset =
> +        section->offset_within_address_space - section->offset_within_region;
> +    iommu->dev = v;
> +
> +    ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
> +    if (ret) {
> +        g_free(iommu);
> +        return;
> +    }
> +
> +    QLIST_INSERT_HEAD(&v->iommu_list, iommu, iommu_next);
> +    memory_region_iommu_replay(iommu->iommu_mr, &iommu->n);
> +
> +    return;
> +}
> +
> +static void vhost_vdpa_iommu_region_del(MemoryListener *listener,
> +                                        MemoryRegionSection *section)
> +{
> +    struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener);
> +
> +    struct vdpa_iommu *iommu;
> +
> +    QLIST_FOREACH(iommu, &v->iommu_list, iommu_next)
> +    {
> +        if (MEMORY_REGION(iommu->iommu_mr) == section->mr &&
> +            iommu->n.start == section->offset_within_region) {
> +            memory_region_unregister_iommu_notifier(section->mr, &iommu->n);
> +            QLIST_REMOVE(iommu, iommu_next);
> +            g_free(iommu);
> +            break;
> +        }
> +    }
> +}
> +
>  static void vhost_vdpa_listener_region_add(MemoryListener *listener,
>                                             MemoryRegionSection *section)
>  {
> @@ -186,6 +278,10 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener,
>                                              v->iova_range.last)) {
>          return;
>      }
> +    if (memory_region_is_iommu(section->mr)) {
> +        vhost_vdpa_iommu_region_add(listener, section);
> +        return;
> +    }
>  
>      if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
>                   (section->offset_within_region & ~TARGET_PAGE_MASK))) {
> @@ -260,6 +356,10 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener,
>                                              v->iova_range.last)) {
>          return;
>      }
> +    if (memory_region_is_iommu(section->mr)) {
> +        vhost_vdpa_iommu_region_del(listener, section);
> +        return;
> +    }
>  
>      if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
>                   (section->offset_within_region & ~TARGET_PAGE_MASK))) {
> @@ -312,6 +412,7 @@ static const MemoryListener vhost_vdpa_memory_listener = {
>      .region_del = vhost_vdpa_listener_region_del,
>  };
>  
> +
>  static int vhost_vdpa_call(struct vhost_dev *dev, unsigned long int request,
>                               void *arg)
>  {
> @@ -587,7 +688,6 @@ static int vhost_vdpa_cleanup(struct vhost_dev *dev)
>      v = dev->opaque;
>      trace_vhost_vdpa_cleanup(dev, v);
>      vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs);
> -    memory_listener_unregister(&v->listener);
>      vhost_vdpa_svq_cleanup(dev);
>  
>      dev->opaque = NULL;
> @@ -1127,7 +1227,8 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
>      }
>  
>      if (started) {
> -        memory_listener_register(&v->listener, &address_space_memory);
> +        memory_listener_register(&v->listener, dev->vdev->dma_as);
> +
>          return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
>      } else {
>          vhost_vdpa_reset_device(dev);
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index d10a89303e..64a46e37cb 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -41,8 +41,18 @@ typedef struct vhost_vdpa {
>      void *shadow_vq_ops_opaque;
>      struct vhost_dev *dev;
>      VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
> +    QLIST_HEAD(, vdpa_iommu) iommu_list;
> +    IOMMUNotifier n;
>  } VhostVDPA;
>  
> +struct vdpa_iommu {
> +    struct vhost_vdpa *dev;
> +    IOMMUMemoryRegion *iommu_mr;
> +    hwaddr iommu_offset;
> +    IOMMUNotifier n;
> +    QLIST_ENTRY(vdpa_iommu) iommu_next;
> +};
> +
>  int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr size,
>                         void *vaddr, bool readonly);
>  int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, hwaddr iova, hwaddr size);
> -- 
> 2.34.3