Re: [Qemu-devel] [RFC v2 07/28] hw/vfio/common: Refactor container initialization

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

Hi Greg,
On 10/22/18 4:39 PM, Greg Kurz wrote:
> On Fri, 21 Sep 2018 10:17:58 +0200
> Eric Auger <eric.auger@redhat.com> wrote:
> 
>> To prepare for testing yet another extension, let's
>> refactor the code. We introduce vfio_iommu_get_type()
>> helper which selects the richest API (v2 first). Then
>> vfio_init_container() does the SET_CONTAINER and
>> SET_IOMMU ioctl calls. So we end up with a switch/case
>> on the iommu_type which should be a little bit more readable
>> when introducing the NESTING extension check. Also ioctl's
>> get called once per iommu_type.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> ---
>>  hw/vfio/common.c | 102 ++++++++++++++++++++++++++++++-----------------
>>  1 file changed, 65 insertions(+), 37 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 7c185e5a2e..53b8f773cc 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -1036,12 +1036,58 @@ static void vfio_put_address_space(VFIOAddressSpace *space)
>>      }
>>  }
>>  
>> +/*
>> + * vfio_iommu_get_type - selects the richest iommu_type (v2 first)
>> + * nested only is selected if requested by @force_nested
> 
> It seems the second line belongs to patch 8.
Yes it does. thanks for spotting that.
> 
> Appart from that, this definitely makes the code more readable.
> 
> Reviewed-by: Greg Kurz <groug@kaod.org>

I will send this patch separately.

Thanks

Eric
> 
>> + */
>> +static int vfio_iommu_get_type(VFIOContainer *container,
>> +                               Error **errp)
>> +{
>> +    int fd = container->fd;
>> +
>> +    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) {
>> +        return VFIO_TYPE1v2_IOMMU;
>> +    } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
>> +        return VFIO_TYPE1_IOMMU;
>> +    } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU)) {
>> +        return VFIO_SPAPR_TCE_v2_IOMMU;
>> +    } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) {
>> +        return VFIO_SPAPR_TCE_IOMMU;
>> +    } else {
>> +        error_setg(errp, "No available IOMMU models");
>> +        return -EINVAL;
>> +    }
>> +}
>> +
>> +static int vfio_init_container(VFIOContainer *container, int group_fd,
>> +                               int iommu_type, Error **errp)
>> +{
>> +    int ret;
>> +
>> +    ret = ioctl(group_fd, VFIO_GROUP_SET_CONTAINER, &container->fd);
>> +    if (ret) {
>> +        error_setg_errno(errp, errno, "failed to set group container");
>> +        return -errno;
>> +    }
>> +
>> +    ret = ioctl(container->fd, VFIO_SET_IOMMU, iommu_type);
>> +    if (ret) {
>> +        error_setg_errno(errp, errno, "failed to set iommu for container");
>> +        return -errno;
>> +    }
>> +    container->iommu_type = iommu_type;
>> +    return 0;
>> +}
>> +
>>  static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
>>                                    Error **errp)
>>  {
>>      VFIOContainer *container;
>>      int ret, fd;
>>      VFIOAddressSpace *space;
>> +    int iommu_type;
>> +    bool v2 = false;
>> +
>>  
>>      space = vfio_get_address_space(as);
>>  
>> @@ -1101,23 +1147,20 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
>>      container->fd = fd;
>>      QLIST_INIT(&container->giommu_list);
>>      QLIST_INIT(&container->hostwin_list);
>> -    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU) ||
>> -        ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) {
>> -        bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU);
>> +
>> +    iommu_type = vfio_iommu_get_type(container, errp);
>> +    if (iommu_type < 0) {
>> +            goto free_container_exit;
>> +    }
>> +
>> +    switch (iommu_type) {
>> +    case VFIO_TYPE1v2_IOMMU:
>> +    case VFIO_TYPE1_IOMMU:
>> +    {
>>          struct vfio_iommu_type1_info info;
>>  
>> -        ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
>> +        ret = vfio_init_container(container, group->fd, iommu_type, errp);
>>          if (ret) {
>> -            error_setg_errno(errp, errno, "failed to set group container");
>> -            ret = -errno;
>> -            goto free_container_exit;
>> -        }
>> -
>> -        container->iommu_type = v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU;
>> -        ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
>> -        if (ret) {
>> -            error_setg_errno(errp, errno, "failed to set iommu for container");
>> -            ret = -errno;
>>              goto free_container_exit;
>>          }
>>  
>> @@ -1137,28 +1180,16 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
>>          }
>>          vfio_host_win_add(container, 0, (hwaddr)-1, info.iova_pgsizes);
>>          container->pgsizes = info.iova_pgsizes;
>> -    } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU) ||
>> -               ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU)) {
>> +        break;
>> +    }
>> +    case VFIO_SPAPR_TCE_v2_IOMMU:
>> +        v2 = true;
>> +    case VFIO_SPAPR_TCE_IOMMU:
>> +    {
>>          struct vfio_iommu_spapr_tce_info info;
>> -        bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU);
>>  
>> -        ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
>> +        ret = vfio_init_container(container, group->fd, iommu_type, errp);
>>          if (ret) {
>> -            error_setg_errno(errp, errno, "failed to set group container");
>> -            ret = -errno;
>> -            goto free_container_exit;
>> -        }
>> -        container->iommu_type =
>> -            v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU;
>> -        ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
>> -        if (ret) {
>> -            container->iommu_type = VFIO_SPAPR_TCE_IOMMU;
>> -            v2 = false;
>> -            ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
>> -        }
>> -        if (ret) {
>> -            error_setg_errno(errp, errno, "failed to set iommu for container");
>> -            ret = -errno;
>>              goto free_container_exit;
>>          }
>>  
>> @@ -1222,10 +1253,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
>>                                info.dma32_window_size - 1,
>>                                0x1000);
>>          }
>> -    } else {
>> -        error_setg(errp, "No available IOMMU models");
>> -        ret = -EINVAL;
>> -        goto free_container_exit;
>> +    }
>>      }
>>  
>>      vfio_kvm_device_add_group(group);
> 
>