Re: [RFC v2 4/7] virtio-iommu: Compute host reserved regions

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

Hi Zhenzhong,

On 6/11/24 05:25, Duan, Zhenzhong wrote:
>
>> -----Original Message-----
>> From: Eric Auger <eric.auger@redhat.com>
>> Subject: [RFC v2 4/7] virtio-iommu: Compute host reserved regions
>>
>> Compute the host reserved regions in virtio_iommu_set_iommu_device().
>> The usable IOVA regions are retrieved from the HOSTIOMMUDevice.
>> The virtio_iommu_set_host_iova_ranges() helper turns usable regions
>> into complementary reserved regions while testing the inclusion
>> into existing ones. virtio_iommu_set_host_iova_ranges() reuse the
>> implementation of virtio_iommu_set_iova_ranges() which will be	
>> removed in subsequent patches. rebuild_resv_regions() is just moved.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> ---
>> hw/virtio/virtio-iommu.c | 151 ++++++++++++++++++++++++++++++--------
>> -
>> 1 file changed, 117 insertions(+), 34 deletions(-)
>>
>> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
>> index 0680a357f0..33e9682b83 100644
>> --- a/hw/virtio/virtio-iommu.c
>> +++ b/hw/virtio/virtio-iommu.c
>> @@ -494,12 +494,114 @@ get_host_iommu_device(VirtIOIOMMU
>> *viommu, PCIBus *bus, int devfn) {
>>     return g_hash_table_lookup(viommu->host_iommu_devices, &key);
>> }
>>
>> +/**
>> + * rebuild_resv_regions: rebuild resv regions with both the
>> + * info of host resv ranges and property set resv ranges
>> + */
>> +static int rebuild_resv_regions(IOMMUDevice *sdev)
>> +{
>> +    GList *l;
>> +    int i = 0;
>> +
>> +    /* free the existing list and rebuild it from scratch */
>> +    g_list_free_full(sdev->resv_regions, g_free);
>> +    sdev->resv_regions = NULL;
>> +
>> +    /* First add host reserved regions if any, all tagged as RESERVED */
>> +    for (l = sdev->host_resv_ranges; l; l = l->next) {
>> +        ReservedRegion *reg = g_new0(ReservedRegion, 1);
>> +        Range *r = (Range *)l->data;
>> +
>> +        reg->type = VIRTIO_IOMMU_RESV_MEM_T_RESERVED;
>> +        range_set_bounds(&reg->range, range_lob(r), range_upb(r));
>> +        sdev->resv_regions = resv_region_list_insert(sdev->resv_regions, reg);
>> +        trace_virtio_iommu_host_resv_regions(sdev-
>>> iommu_mr.parent_obj.name, i,
>> +                                             range_lob(&reg->range),
>> +                                             range_upb(&reg->range));
>> +        i++;
>> +    }
>> +    /*
>> +     * then add higher priority reserved regions set by the machine
>> +     * through properties
>> +     */
>> +    add_prop_resv_regions(sdev);
>> +    return 0;
>> +}
>> +
>> +static int virtio_iommu_set_host_iova_ranges(VirtIOIOMMU *s, PCIBus
>> *bus,
>> +                                             int devfn, GList *iova_ranges,
>> +                                             Error **errp)
>> +{
>> +    IOMMUPciBus *sbus = g_hash_table_lookup(s->as_by_busptr, bus);
>> +    IOMMUDevice *sdev;
>> +    GList *current_ranges;
>> +    GList *l, *tmp, *new_ranges = NULL;
>> +    int ret = -EINVAL;
>> +
>> +    if (!sbus) {
>> +        error_report("%s no sbus", __func__);
>> +    }
>> +
>> +    sdev = sbus->pbdev[devfn];
>> +
>> +    current_ranges = sdev->host_resv_ranges;
>> +
>> +    if (sdev->probe_done) {
> Will this still happen with new interface?
no this shouldn't. Replaced by a g_assert(!sdev->probe_done) to make
sure the i/f is used properly.
>
>> +        error_setg(errp,
>> +                   "%s: Notified about new host reserved regions after probe",
>> +                   __func__);
>> +        goto out;
>> +    }
>> +
>> +    /* check that each new resv region is included in an existing one */
>> +    if (sdev->host_resv_ranges) {
> Same here.
To me this one can still happen in case several devices belong to the
same group.
>
>> +        range_inverse_array(iova_ranges,
>> +                            &new_ranges,
>> +                            0, UINT64_MAX);
>> +
>> +        for (tmp = new_ranges; tmp; tmp = tmp->next) {
>> +            Range *newr = (Range *)tmp->data;
>> +            bool included = false;
>> +
>> +            for (l = current_ranges; l; l = l->next) {
>> +                Range * r = (Range *)l->data;
>> +
>> +                if (range_contains_range(r, newr)) {
>> +                    included = true;
>> +                    break;
>> +                }
>> +            }
>> +            if (!included) {
>> +                goto error;
>> +            }
>> +        }
>> +        /* all new reserved ranges are included in existing ones */
>> +        ret = 0;
>> +        goto out;
>> +    }
>> +
>> +    range_inverse_array(iova_ranges,
>> +                        &sdev->host_resv_ranges,
>> +                        0, UINT64_MAX);
>> +    rebuild_resv_regions(sdev);
>> +
>> +    return 0;
>> +error:
>> +    error_setg(errp, "%s Conflicting host reserved ranges set!",
>> +               __func__);
>> +out:
>> +    g_list_free_full(new_ranges, g_free);
>> +    return ret;
>> +}
>> +
>> static bool virtio_iommu_set_iommu_device(PCIBus *bus, void *opaque,
>> int devfn,
>>                                           HostIOMMUDevice *hiod, Error **errp)
>> {
>>     VirtIOIOMMU *viommu = opaque;
>>     VirtioHostIOMMUDevice *vhiod;
>> +    HostIOMMUDeviceClass *hiodc =
>> HOST_IOMMU_DEVICE_GET_CLASS(hiod);
>>     struct hiod_key *new_key;
>> +    GList *host_iova_ranges = NULL;
> g_autoptr(GList)?
are you sure this frees all the elements of the list? As of now I would
be tempted to leave the code as is.

Thanks

Eric
>
> Thanks
> Zhenzhong
>
>>     assert(hiod);
>>
>> @@ -509,6 +611,20 @@ static bool
>> virtio_iommu_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
>>         return false;
>>     }
>>
>> +    if (hiodc->get_iova_ranges) {
>> +        int ret;
>> +        host_iova_ranges = hiodc->get_iova_ranges(hiod, errp);
>> +        if (!host_iova_ranges) {
>> +            return true; /* some old kernels may not support that capability */
>> +        }
>> +        ret = virtio_iommu_set_host_iova_ranges(viommu, bus, devfn,
>> +                                                host_iova_ranges, errp);
>> +        if (ret) {
>> +            g_list_free_full(host_iova_ranges, g_free);
>> +            return false;
>> +        }
>> +    }
>> +
>>     vhiod = g_malloc0(sizeof(VirtioHostIOMMUDevice));
>>     vhiod->bus = bus;
>>     vhiod->devfn = (uint8_t)devfn;
>> @@ -521,6 +637,7 @@ static bool
>> virtio_iommu_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
>>
>>     object_ref(hiod);
>>     g_hash_table_insert(viommu->host_iommu_devices, new_key, vhiod);
>> +    g_list_free_full(host_iova_ranges, g_free);
>>
>>     return true;
>> }
>> @@ -1243,40 +1360,6 @@ static int
>> virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr,
>>     return 0;
>> }
>>
>> -/**
>> - * rebuild_resv_regions: rebuild resv regions with both the
>> - * info of host resv ranges and property set resv ranges
>> - */
>> -static int rebuild_resv_regions(IOMMUDevice *sdev)
>> -{
>> -    GList *l;
>> -    int i = 0;
>> -
>> -    /* free the existing list and rebuild it from scratch */
>> -    g_list_free_full(sdev->resv_regions, g_free);
>> -    sdev->resv_regions = NULL;
>> -
>> -    /* First add host reserved regions if any, all tagged as RESERVED */
>> -    for (l = sdev->host_resv_ranges; l; l = l->next) {
>> -        ReservedRegion *reg = g_new0(ReservedRegion, 1);
>> -        Range *r = (Range *)l->data;
>> -
>> -        reg->type = VIRTIO_IOMMU_RESV_MEM_T_RESERVED;
>> -        range_set_bounds(&reg->range, range_lob(r), range_upb(r));
>> -        sdev->resv_regions = resv_region_list_insert(sdev->resv_regions, reg);
>> -        trace_virtio_iommu_host_resv_regions(sdev-
>>> iommu_mr.parent_obj.name, i,
>> -                                             range_lob(&reg->range),
>> -                                             range_upb(&reg->range));
>> -        i++;
>> -    }
>> -    /*
>> -     * then add higher priority reserved regions set by the machine
>> -     * through properties
>> -     */
>> -    add_prop_resv_regions(sdev);
>> -    return 0;
>> -}
>> -
>> /**
>>  * virtio_iommu_set_iova_ranges: Conveys the usable IOVA ranges
>>  *
>> --
>> 2.41.0