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Re: [PATCH v15 4/4] vhost-vdpa: Add support for vIOMMU.


From: Jason Wang
Subject: Re: [PATCH v15 4/4] vhost-vdpa: Add support for vIOMMU.
Date: Thu, 23 Mar 2023 11:47:13 +0800

On Tue, Mar 21, 2023 at 10:24 PM Cindy Lu <lulu@redhat.com> wrote:
>
> 1. The vIOMMU support will make vDPA can work in IOMMU mode. This
> will fix security issues while using the no-IOMMU mode.
> To support this feature we need to add new functions for IOMMU MR adds and
> deletes.
>
> Also since the SVQ does not support vIOMMU yet, add the check for IOMMU
> in vhost_vdpa_dev_start, if the SVQ and IOMMU enable at the same time
> the function will return fail.
>
> 2. Skip the iova_max check vhost_vdpa_listener_skipped_section(). While
> MR is IOMMU, move this check to vhost_vdpa_iommu_map_notify()
>
> Verified in vp_vdpa and vdpa_sim_net driver
>
> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---
>  hw/virtio/trace-events         |   2 +-
>  hw/virtio/vhost-vdpa.c         | 159 ++++++++++++++++++++++++++++++---
>  include/hw/virtio/vhost-vdpa.h |  11 +++
>  3 files changed, 161 insertions(+), 11 deletions(-)
>
> diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
> index 8f8d05cf9b..de4da2c65c 100644
> --- a/hw/virtio/trace-events
> +++ b/hw/virtio/trace-events
> @@ -33,7 +33,7 @@ vhost_user_create_notifier(int idx, void *n) "idx:%d n:%p"
>  vhost_vdpa_dma_map(void *vdpa, int fd, uint32_t msg_type, uint32_t asid, 
> uint64_t iova, uint64_t size, uint64_t uaddr, uint8_t perm, uint8_t type) 
> "vdpa:%p fd: %d msg_type: %"PRIu32" asid: %"PRIu32" iova: 0x%"PRIx64" size: 
> 0x%"PRIx64" uaddr: 0x%"PRIx64" perm: 0x%"PRIx8" type: %"PRIu8
>  vhost_vdpa_dma_unmap(void *vdpa, int fd, uint32_t msg_type, uint32_t asid, 
> uint64_t iova, uint64_t size, uint8_t type) "vdpa:%p fd: %d msg_type: 
> %"PRIu32" asid: %"PRIu32" iova: 0x%"PRIx64" size: 0x%"PRIx64" type: %"PRIu8
>  vhost_vdpa_listener_begin_batch(void *v, int fd, uint32_t msg_type, uint8_t 
> type)  "vdpa:%p fd: %d msg_type: %"PRIu32" type: %"PRIu8
> -vhost_vdpa_listener_commit(void *v, int fd, uint32_t msg_type, uint8_t type) 
>  "vdpa:%p fd: %d msg_type: %"PRIu32" type: %"PRIu8
> +vhost_vdpa_iotlb_batch_end_once(void *v, int fd, uint32_t msg_type, uint8_t 
> type)  "vdpa:%p fd: %d msg_type: %"PRIu32" type: %"PRIu8
>  vhost_vdpa_listener_region_add(void *vdpa, uint64_t iova, uint64_t llend, 
> void *vaddr, bool readonly) "vdpa: %p iova 0x%"PRIx64" llend 0x%"PRIx64" 
> vaddr: %p read-only: %d"
>  vhost_vdpa_listener_region_del(void *vdpa, uint64_t iova, uint64_t llend) 
> "vdpa: %p iova 0x%"PRIx64" llend 0x%"PRIx64
>  vhost_vdpa_add_status(void *dev, uint8_t status) "dev: %p status: 0x%"PRIx8
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 0c8c37e786..39720d12a6 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
> @@ -60,13 +61,21 @@ static bool 
> vhost_vdpa_listener_skipped_section(MemoryRegionSection *section,
>                       iova_min, section->offset_within_address_space);
>          return true;
>      }
> +    /*
> +     * While using vIOMMU, sometimes the section will be larger than 
> iova_max,
> +     * but the memory that actually maps is smaller, so move the check to
> +     * function vhost_vdpa_iommu_map_notify(). That function will use the 
> actual
> +     * size that maps to the kernel
> +     */
>
> -    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;
> +    if (!memory_region_is_iommu(section->mr)) {
> +        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;
> @@ -158,9 +167,8 @@ static void vhost_vdpa_iotlb_batch_begin_once(struct 
> vhost_vdpa *v)
>      v->iotlb_batch_begin_sent = true;
>  }
>
> -static void vhost_vdpa_listener_commit(MemoryListener *listener)
> +static void vhost_vdpa_iotlb_batch_end_once(struct vhost_vdpa *v)
>  {
> -    struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, 
> listener);
>      struct vhost_dev *dev = v->dev;
>      struct vhost_msg_v2 msg = {};
>      int fd = v->device_fd;
> @@ -176,7 +184,7 @@ static void vhost_vdpa_listener_commit(MemoryListener 
> *listener)
>      msg.type = v->msg_type;
>      msg.iotlb.type = VHOST_IOTLB_BATCH_END;
>
> -    trace_vhost_vdpa_listener_commit(v, fd, msg.type, msg.iotlb.type);
> +    trace_vhost_vdpa_iotlb_batch_end_once(v, fd, msg.type, msg.iotlb.type);

I suggest to keep the commit trace. The commit and batch are different
things. If you want to trace the batch begin/end you should do it in
vhost_vdpa_iotlb_batch_begin_once() etc.

>      if (write(fd, &msg, sizeof(msg)) != sizeof(msg)) {
>          error_report("failed to write, fd=%d, errno=%d (%s)",
>                       fd, errno, strerror(errno));
> @@ -185,6 +193,124 @@ static void vhost_vdpa_listener_commit(MemoryListener 
> *listener)
>      v->iotlb_batch_begin_sent = false;
>  }
>
> +static void vhost_vdpa_listener_commit(MemoryListener *listener)
> +{
> +    struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, 
> listener);
> +    vhost_vdpa_iotlb_batch_end_once(v);
> +}
> +
> +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;
> +    Int128 llend;
> +
> +    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();
> +    /* check if RAM section out of device range */
> +    llend = int128_add(int128_makes64(iotlb->addr_mask), 
> int128_makes64(iova));
> +    if (int128_gt(llend, int128_make64(v->iova_range.last))) {
> +        error_report("RAM section out of device range (max=0x%" PRIx64
> +                     ", end addr=0x%" PRIx64 ")",
> +                     v->iova_range.last, int128_get64(llend));
> +        return;
> +    }
> +
> +    if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> +        bool read_only;
> +
> +        if (!memory_get_xlat_addr(iotlb, &vaddr, NULL, &read_only, NULL)) {
> +            return;
> +        }
> +        vhost_vdpa_iotlb_batch_begin_once(v);

I think at most 2 ioctls for this, is this still worth to batch them?

Other looks good.

Thanks

> +        ret = vhost_vdpa_dma_map(v, VHOST_VDPA_GUEST_PA_ASID, 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 {
> +        vhost_vdpa_iotlb_batch_begin_once(v);
> +        ret = vhost_vdpa_dma_unmap(v, VHOST_VDPA_GUEST_PA_ASID, 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);
> +        }
> +    }
> +    vhost_vdpa_iotlb_batch_end_once(v);
> +}
> +
> +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)
>  {
> @@ -199,6 +325,10 @@ 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))) {
> @@ -278,6 +408,9 @@ 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);
> +    }
>
>      if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) 
> !=
>                   (section->offset_within_region & ~TARGET_PAGE_MASK))) {
> @@ -1182,7 +1315,13 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, 
> bool started)
>      }
>
>      if (started) {
> -        memory_listener_register(&v->listener, &address_space_memory);
> +        if (vhost_dev_has_iommu(dev) && (v->shadow_vqs_enabled)) {
> +            error_report("SVQ can not work while IOMMU enable, please 
> disable"
> +                         "IOMMU and try again");
> +            return -1;
> +        }
> +        memory_listener_register(&v->listener, dev->vdev->dma_as);
> +
>          return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
>      }
>
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index c278a2a8de..e64bfc7f98 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -52,6 +52,8 @@ typedef struct vhost_vdpa {
>      struct vhost_dev *dev;
>      Error *migration_blocker;
>      VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
> +    QLIST_HEAD(, vdpa_iommu) iommu_list;
> +    IOMMUNotifier n;
>  } VhostVDPA;
>
>  int vhost_vdpa_get_iova_range(int fd, struct vhost_vdpa_iova_range 
> *iova_range);
> @@ -61,4 +63,13 @@ int vhost_vdpa_dma_map(struct vhost_vdpa *v, uint32_t 
> asid, hwaddr iova,
>  int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, uint32_t asid, hwaddr iova,
>                           hwaddr size);
>
> +typedef struct vdpa_iommu {
> +    struct vhost_vdpa *dev;
> +    IOMMUMemoryRegion *iommu_mr;
> +    hwaddr iommu_offset;
> +    IOMMUNotifier n;
> +    QLIST_ENTRY(vdpa_iommu) iommu_next;
> +} VDPAIOMMUState;
> +
> +
>  #endif
> --
> 2.34.3
>




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