Re: [PATCH v3 2/7] virtio-iommu: Implement set|unset]_iommu_device() callbacks

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

Hi Zhenzhong,

On 6/13/24 11:57, Duan, Zhenzhong wrote:
>
>> -----Original Message-----
>> From: Eric Auger <eric.auger@redhat.com>
>> Subject: [PATCH v3 2/7] virtio-iommu: Implement
>> set|unset]_iommu_device() callbacks
>>
>> Implement PCIIOMMUOPs [set|unset]_iommu_device() callbacks.
>> In set(), a VirtioHostIOMMUDevice is allocated which holds
>> a reference to the HostIOMMUDevice. This object is stored in a hash
>> table indexed by PCI BDF. The handle to the Host IOMMU device
>> will allow to retrieve information related to the physical IOMMU.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>
>> ---
>>
>> v2 -> v3:
>> - include host_iommu_device.h in virtio-iommu.h header
>> - introduce hiod_destroy() and fix UAF in
>>  virtio_iommu_unset_iommu_device()	
>> ---
>> include/hw/virtio/virtio-iommu.h | 10 ++++
>> hw/virtio/virtio-iommu.c         | 90
>> ++++++++++++++++++++++++++++++++
>> 2 files changed, 100 insertions(+)
>>
>> diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-
>> iommu.h
>> index 83a52cc446..a5926de947 100644
>> --- a/include/hw/virtio/virtio-iommu.h
>> +++ b/include/hw/virtio/virtio-iommu.h
>> @@ -25,6 +25,7 @@
>> #include "hw/pci/pci.h"
>> #include "qom/object.h"
>> #include "qapi/qapi-types-virtio.h"
>> +#include "sysemu/host_iommu_device.h"
>>
>> #define TYPE_VIRTIO_IOMMU "virtio-iommu-device"
>> #define TYPE_VIRTIO_IOMMU_PCI "virtio-iommu-pci"
>> @@ -45,6 +46,14 @@ typedef struct IOMMUDevice {
>>     bool probe_done;
>> } IOMMUDevice;
>>
>> +typedef struct VirtioHostIOMMUDevice {
>> +    void *viommu;
>> +    PCIBus *bus;
>> +    uint8_t devfn;
>> +    HostIOMMUDevice *dev;
>> +    QLIST_ENTRY(VirtioHostIOMMUDevice) next;
>> +} VirtioHostIOMMUDevice;
> Do you have plan to use the elements in VirtioHostIOMMUDevice?
As of now I get rid of this derived object and do something similar as
what you did on vtd.
>
>> +
>> typedef struct IOMMUPciBus {
>>     PCIBus       *bus;
>>     IOMMUDevice  *pbdev[]; /* Parent array is sparse, so dynamically alloc
>> */
>> @@ -57,6 +66,7 @@ struct VirtIOIOMMU {
>>     struct virtio_iommu_config config;
>>     uint64_t features;
>>     GHashTable *as_by_busptr;
>> +    GHashTable *host_iommu_devices;
>>     IOMMUPciBus *iommu_pcibus_by_bus_num[PCI_BUS_MAX];
>>     PCIBus *primary_bus;
>>     ReservedRegion *prop_resv_regions;
>> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
>> index 1326c6ec41..db842555c8 100644
>> --- a/hw/virtio/virtio-iommu.c
>> +++ b/hw/virtio/virtio-iommu.c
>> @@ -69,6 +69,11 @@ typedef struct VirtIOIOMMUMapping {
>>     uint32_t flags;
>> } VirtIOIOMMUMapping;
>>
>> +struct hiod_key {
>> +    PCIBus *bus;
>> +    uint8_t devfn;
>> +};
>> +
>> static inline uint16_t virtio_iommu_get_bdf(IOMMUDevice *dev)
>> {
>>     return PCI_BUILD_BDF(pci_bus_num(dev->bus), dev->devfn);
>> @@ -462,8 +467,90 @@ static AddressSpace
>> *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
>>     return &sdev->as;
>> }
>>
>> +static gboolean hiod_equal(gconstpointer v1, gconstpointer v2)
>> +{
>> +    const struct hiod_key *key1 = v1;
>> +    const struct hiod_key *key2 = v2;
>> +
>> +    return (key1->bus == key2->bus) && (key1->devfn == key2->devfn);
>> +}
>> +
>> +static guint hiod_hash(gconstpointer v)
>> +{
>> +    const struct hiod_key *key = v;
>> +    guint value = (guint)(uintptr_t)key->bus;
>> +
>> +    return (guint)(value << 8 | key->devfn);
>> +}
>> +
>> +static void hiod_destroy(gpointer v)
>> +{
>> +    object_unref(v);
> This is a bit different from intel_iommu, here v represents VirtioHostIOMMUDevice *.
damned, you are totally right.

Fixed in next version.

Thank you very much!

Eric
>
> Thanks
> Zhenzhong
>
>> +}
>> +
>> +static VirtioHostIOMMUDevice *
>> +get_host_iommu_device(VirtIOIOMMU *viommu, PCIBus *bus, int devfn) {
>> +    struct hiod_key key = {
>> +        .bus = bus,
>> +        .devfn = devfn,
>> +    };
>> +
>> +    return g_hash_table_lookup(viommu->host_iommu_devices, &key);
>> +}
>> +
>> +static bool virtio_iommu_set_iommu_device(PCIBus *bus, void *opaque,
>> int devfn,
>> +                                          HostIOMMUDevice *hiod, Error **errp)
>> +{
>> +    VirtIOIOMMU *viommu = opaque;
>> +    VirtioHostIOMMUDevice *vhiod;
>> +    struct hiod_key *new_key;
>> +
>> +    assert(hiod);
>> +
>> +    vhiod = get_host_iommu_device(viommu, bus, devfn);
>> +    if (vhiod) {
>> +        error_setg(errp, "VirtioHostIOMMUDevice already exists");
>> +        return false;
>> +    }
>> +
>> +    vhiod = g_malloc0(sizeof(VirtioHostIOMMUDevice));
>> +    vhiod->bus = bus;
>> +    vhiod->devfn = (uint8_t)devfn;
>> +    vhiod->viommu = viommu;
>> +    vhiod->dev = hiod;
>> +
>> +    new_key = g_malloc(sizeof(*new_key));
>> +    new_key->bus = bus;
>> +    new_key->devfn = devfn;
>> +
>> +    object_ref(hiod);
>> +    g_hash_table_insert(viommu->host_iommu_devices, new_key, vhiod);
>> +
>> +    return true;
>> +}
>> +
>> +static void
>> +virtio_iommu_unset_iommu_device(PCIBus *bus, void *opaque, int devfn)
>> +{
>> +    VirtIOIOMMU *viommu = opaque;
>> +    VirtioHostIOMMUDevice *vhiod;
>> +    struct hiod_key key = {
>> +        .bus = bus,
>> +        .devfn = devfn,
>> +    };
>> +
>> +    vhiod = g_hash_table_lookup(viommu->host_iommu_devices, &key);
>> +    if (!vhiod) {
>> +        return;
>> +    }
>> +
>> +    g_hash_table_remove(viommu->host_iommu_devices, &key);
>> +}
>> +
>> static const PCIIOMMUOps virtio_iommu_ops = {
>>     .get_address_space = virtio_iommu_find_add_as,
>> +    .set_iommu_device = virtio_iommu_set_iommu_device,
>> +    .unset_iommu_device = virtio_iommu_unset_iommu_device,
>> };
>>
>> static int virtio_iommu_attach(VirtIOIOMMU *s,
>> @@ -1357,6 +1444,9 @@ static void
>> virtio_iommu_device_realize(DeviceState *dev, Error **errp)
>>
>>     s->as_by_busptr = g_hash_table_new_full(NULL, NULL, NULL, g_free);
>>
>> +    s->host_iommu_devices = g_hash_table_new_full(hiod_hash,
>> hiod_equal,
>> +                                                  g_free, hiod_destroy);
>> +
>>     if (s->primary_bus) {
>>         pci_setup_iommu(s->primary_bus, &virtio_iommu_ops, s);
>>     } else {
>> --
>> 2.41.0