Re: [PATCH v6 18/19] intel_iommu: Implement [set|unset]_iommu_device() callbacks

[Eric Auger <eric.auger@redhat.com>]

On 6/3/24 08:10, Zhenzhong Duan wrote:
> From: Yi Liu <yi.l.liu@intel.com>
>
> Implement [set|unset]_iommu_device() callbacks in Intel vIOMMU.
> In set call, a new structure VTDHostIOMMUDevice which holds
> a reference to HostIOMMUDevice is stored in hash table
> indexed by PCI BDF.
>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  hw/i386/intel_iommu_internal.h |  9 ++++
>  include/hw/i386/intel_iommu.h  |  2 +
>  hw/i386/intel_iommu.c          | 76 ++++++++++++++++++++++++++++++++++
>  3 files changed, 87 insertions(+)
>
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index f8cf99bddf..b800d62ca0 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -28,6 +28,7 @@
>  #ifndef HW_I386_INTEL_IOMMU_INTERNAL_H
>  #define HW_I386_INTEL_IOMMU_INTERNAL_H
>  #include "hw/i386/intel_iommu.h"
> +#include "sysemu/host_iommu_device.h"
>  
>  /*
>   * Intel IOMMU register specification
> @@ -537,4 +538,12 @@ typedef struct VTDRootEntry VTDRootEntry;
>  #define VTD_SL_IGN_COM              0xbff0000000000000ULL
>  #define VTD_SL_TM                   (1ULL << 62)
>  
> +
> +typedef struct VTDHostIOMMUDevice {
> +    IntelIOMMUState *iommu_state;
> +    PCIBus *bus;
> +    uint8_t devfn;
> +    HostIOMMUDevice *dev;
> +    QLIST_ENTRY(VTDHostIOMMUDevice) next;
> +} VTDHostIOMMUDevice;
>  #endif
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index 7d694b0813..2bbde41e45 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -293,6 +293,8 @@ struct IntelIOMMUState {
>      /* list of registered notifiers */
>      QLIST_HEAD(, VTDAddressSpace) vtd_as_with_notifiers;
>  
> +    GHashTable *vtd_host_iommu_dev;             /* VTDHostIOMMUDevice */
> +
>      /* interrupt remapping */
>      bool intr_enabled;              /* Whether guest enabled IR */
>      dma_addr_t intr_root;           /* Interrupt remapping table pointer */
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 519063c8f8..747c988bc4 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -237,6 +237,13 @@ static gboolean vtd_as_equal(gconstpointer v1, gconstpointer v2)
>             (key1->pasid == key2->pasid);
>  }
>  
> +static gboolean vtd_as_idev_equal(gconstpointer v1, gconstpointer v2)
> +{
> +    const struct vtd_as_key *key1 = v1;
> +    const struct vtd_as_key *key2 = v2;
> +
> +    return (key1->bus == key2->bus) && (key1->devfn == key2->devfn);
> +}
>  /*
>   * Note that we use pointer to PCIBus as the key, so hashing/shifting
>   * based on the pointer value is intended. Note that we deal with
> @@ -3812,6 +3819,70 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
>      return vtd_dev_as;
>  }
>  
> +static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
> +                                     HostIOMMUDevice *hiod, Error **errp)
> +{
> +    IntelIOMMUState *s = opaque;
> +    VTDHostIOMMUDevice *vtd_hdev;
> +    struct vtd_as_key key = {
> +        .bus = bus,
> +        .devfn = devfn,
> +    };
> +    struct vtd_as_key *new_key;
> +
> +    assert(hiod);
> +
> +    vtd_iommu_lock(s);
> +
> +    vtd_hdev = g_hash_table_lookup(s->vtd_host_iommu_dev, &key);
> +
> +    if (vtd_hdev) {
> +        error_setg(errp, "IOMMUFD device already exist");
> +        vtd_iommu_unlock(s);
> +        return false;
> +    }
> +
> +    vtd_hdev = g_malloc0(sizeof(VTDHostIOMMUDevice));
> +    vtd_hdev->bus = bus;
> +    vtd_hdev->devfn = (uint8_t)devfn;
> +    vtd_hdev->iommu_state = s;
> +    vtd_hdev->dev = hiod;
I am still not totally clear about why we couldn't reuse VTDAddressSpace
instance for this bus/devid. Is it a matter of aliased versus non
aliased bus/devfn, or a matter of pasid diff. An AddressSpace could back
an assigned device in which case a HostIOMMUDevice could be added to
this latter. I think this should be explained in the commit msg

Eric
> +
> +    new_key = g_malloc(sizeof(*new_key));
> +    new_key->bus = bus;
> +    new_key->devfn = devfn;
> +
> +    object_ref(hiod);
> +    g_hash_table_insert(s->vtd_host_iommu_dev, new_key, vtd_hdev);
> +
> +    vtd_iommu_unlock(s);
> +
> +    return true;
> +}
> +
> +static void vtd_dev_unset_iommu_device(PCIBus *bus, void *opaque, int devfn)
> +{
> +    IntelIOMMUState *s = opaque;
> +    VTDHostIOMMUDevice *vtd_hdev;
> +    struct vtd_as_key key = {
> +        .bus = bus,
> +        .devfn = devfn,
> +    };
> +
> +    vtd_iommu_lock(s);
> +
> +    vtd_hdev = g_hash_table_lookup(s->vtd_host_iommu_dev, &key);
> +    if (!vtd_hdev) {
> +        vtd_iommu_unlock(s);
> +        return;
> +    }
> +
> +    g_hash_table_remove(s->vtd_host_iommu_dev, &key);
> +    object_unref(vtd_hdev->dev);
> +
> +    vtd_iommu_unlock(s);
> +}
> +
>  /* Unmap the whole range in the notifier's scope. */
>  static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
>  {
> @@ -4116,6 +4187,8 @@ static AddressSpace *vtd_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
>  
>  static PCIIOMMUOps vtd_iommu_ops = {
>      .get_address_space = vtd_host_dma_iommu,
> +    .set_iommu_device = vtd_dev_set_iommu_device,
> +    .unset_iommu_device = vtd_dev_unset_iommu_device,
>  };
>  
>  static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
> @@ -4235,6 +4308,9 @@ static void vtd_realize(DeviceState *dev, Error **errp)
>                                       g_free, g_free);
>      s->vtd_address_spaces = g_hash_table_new_full(vtd_as_hash, vtd_as_equal,
>                                        g_free, g_free);
> +    s->vtd_host_iommu_dev = g_hash_table_new_full(vtd_as_hash,
> +                                                  vtd_as_idev_equal,
> +                                                  g_free, g_free);
>      vtd_init(s);
>      pci_setup_iommu(bus, &vtd_iommu_ops, dev);
>      /* Pseudo address space under root PCI bus. */