RE: [PATCH v6 06/21] vfio/iommufd: Add support for iova_ranges and pgsizes

[Duan, Zhenzhong]

>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Sent: Tuesday, November 14, 2023 9:46 PM
>Subject: Re: [PATCH v6 06/21] vfio/iommufd: Add support for iova_ranges and
>pgsizes
>
>On 11/14/23 11:09, Zhenzhong Duan wrote:
>> Some vIOMMU such as virtio-iommu use IOVA ranges from host side to
>> setup reserved ranges for passthrough device, so that guest will not
>> use an IOVA range beyond host support.
>>
>> Use an uAPI of IOMMUFD to get IOVA ranges of host side and pass to
>> vIOMMU just like the legacy backend, if this fails, fallback to
>> 64bit IOVA range.
>>
>> Also use out_iova_alignment returned from uAPI as pgsizes instead of
>> qemu_real_host_page_size() as a fallback.
>>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>> v6: propagate iommufd_cdev_get_info_iova_range err and print as warning
>>
>>   hw/vfio/iommufd.c | 55
>++++++++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 54 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
>> index 06282d885c..e5bf528e89 100644
>> --- a/hw/vfio/iommufd.c
>> +++ b/hw/vfio/iommufd.c
>> @@ -267,6 +267,53 @@ static int
>iommufd_cdev_ram_block_discard_disable(bool state)
>>       return ram_block_uncoordinated_discard_disable(state);
>>   }
>>
>> +static int iommufd_cdev_get_info_iova_range(VFIOIOMMUFDContainer
>*container,
>> +                                            uint32_t ioas_id, Error **errp)
>> +{
>> +    VFIOContainerBase *bcontainer = &container->bcontainer;
>> +    struct iommu_ioas_iova_ranges *info;
>> +    struct iommu_iova_range *iova_ranges;
>> +    int ret, sz, fd = container->be->fd;
>> +
>> +    info = g_malloc0(sizeof(*info));
>> +    info->size = sizeof(*info);
>> +    info->ioas_id = ioas_id;
>> +
>> +    ret = ioctl(fd, IOMMU_IOAS_IOVA_RANGES, info);
>> +    if (ret && errno != EMSGSIZE) {
>> +        goto error;
>> +    }
>> +
>> +    sz = info->num_iovas * sizeof(struct iommu_iova_range);
>> +    info = g_realloc(info, sizeof(*info) + sz);
>> +    info->allowed_iovas = (uintptr_t)(info + 1);
>> +
>> +    ret = ioctl(fd, IOMMU_IOAS_IOVA_RANGES, info);
>> +    if (ret) {
>> +        goto error;
>> +    }
>> +
>> +    iova_ranges = (struct iommu_iova_range *)(uintptr_t)info->allowed_iovas;
>> +
>> +    for (int i = 0; i < info->num_iovas; i++) {
>> +        Range *range = g_new(Range, 1);
>> +
>> +        range_set_bounds(range, iova_ranges[i].start, iova_ranges[i].last);
>> +        bcontainer->iova_ranges =
>> +            range_list_insert(bcontainer->iova_ranges, range);
>> +    }
>> +    bcontainer->pgsizes = info->out_iova_alignment;
>> +
>> +    g_free(info);
>> +    return 0;
>> +
>> +error:
>> +    ret = -errno;
>> +    g_free(info);
>> +    error_setg_errno(errp, errno, "Cannot get IOVA ranges");
>> +    return ret;
>> +}
>> +
>>   static int iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,
>>                                  AddressSpace *as, Error **errp)
>>   {
>> @@ -341,7 +388,13 @@ static int iommufd_cdev_attach(const char *name,
>VFIODevice *vbasedev,
>>           goto err_discard_disable;
>>       }
>>
>> -    bcontainer->pgsizes = qemu_real_host_page_size();
>> +    ret = iommufd_cdev_get_info_iova_range(container, ioas_id, &err);
>> +    if (ret) {
>> +        warn_report_err(err);
>> +        err = NULL;
>> +        error_printf("Fallback to default 64bit IOVA range and 4K page 
>> size\n");
>
>This would be better :
>
>         error_append_hint(&err,
>                    "Fallback to default 64bit IOVA range and 4K page size\n");
>         warn_report_err(err);
>
>I will take care of it if you agree. With that,

Sure, thanks

BRs
Zhenzhong

>
>Reviewed-by: Cédric Le Goater <clg@redhat.com>
>
>Thanks,
>
>C.
>
>
>> +        bcontainer->pgsizes = qemu_real_host_page_size();
>> +    }
>>
>>       bcontainer->listener = vfio_memory_listener;
>>       memory_listener_register(&bcontainer->listener, bcontainer->space->as);