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RE: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device
From: |
Duan, Zhenzhong |
Subject: |
RE: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device |
Date: |
Wed, 27 Sep 2023 09:58:48 +0000 |
>-----Original Message-----
>From: Eric Auger <eric.auger@redhat.com>
>Sent: Wednesday, September 27, 2023 3:36 PM
>Subject: Re: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device
>
>Hi Zhenzhong,
>
>On 9/26/23 13:32, Zhenzhong Duan wrote:
>> From: Eric Auger <eric.auger@redhat.com>
>>
>> We want the VFIO devices to be able to use two different
>> IOMMU backends, the legacy VFIO one and the new iommufd one.
>>
>> Introduce vfio_[attach/detach]_device which aim at hiding the
>> underlying IOMMU backend (IOCTLs, datatypes, ...).
>>
>> Once vfio_attach_device completes, the device is attached
>> to a security context and its fd can be used. Conversely
>> When vfio_detach_device completes, the device has been
>> detached from the security context.
>>
>> At the moment only the implementation based on the legacy
>> container/group exists. Let's use it from the vfio-pci device.
>> Subsequent patches will handle other devices.
>
>you may add: no functional change intended
Will do.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>> include/hw/vfio/vfio-common.h | 3 ++
>> hw/vfio/common.c | 68 +++++++++++++++++++++++++++++++++++
>> hw/vfio/pci.c | 50 +++-----------------------
>> hw/vfio/trace-events | 2 +-
>> 4 files changed, 77 insertions(+), 46 deletions(-)
>>
>> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
>> index c4e7c3b4a7..12fbfbc37d 100644
>> --- a/include/hw/vfio/vfio-common.h
>> +++ b/include/hw/vfio/vfio-common.h
>> @@ -225,6 +225,9 @@ void vfio_put_group(VFIOGroup *group);
>> struct vfio_device_info *vfio_get_device_info(int fd);
>> int vfio_get_device(VFIOGroup *group, const char *name,
>> VFIODevice *vbasedev, Error **errp);
>> +int vfio_attach_device(char *name, VFIODevice *vbasedev,
>> + AddressSpace *as, Error **errp);
>> +void vfio_detach_device(VFIODevice *vbasedev);
>>
>> int vfio_kvm_device_add_fd(int fd, Error **errp);
>> int vfio_kvm_device_del_fd(int fd, Error **errp);
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 959b1362bb..7f3798b152 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -2611,3 +2611,71 @@ int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
>> }
>> return vfio_eeh_container_op(container, op);
>> }
>> +
>> +static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp)
>> +{
>> + char *tmp, group_path[PATH_MAX], *group_name;
>> + int ret, groupid;
>> + ssize_t len;
>> +
>> + tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
>> + len = readlink(tmp, group_path, sizeof(group_path));
>> + g_free(tmp);
>> +
>> + if (len <= 0 || len >= sizeof(group_path)) {
>> + ret = len < 0 ? -errno : -ENAMETOOLONG;
>> + error_setg_errno(errp, -ret, "no iommu_group found");
>> + return ret;
>> + }
>> +
>> + group_path[len] = 0;
>> +
>> + group_name = basename(group_path);
>> + if (sscanf(group_name, "%d", &groupid) != 1) {
>> + error_setg_errno(errp, errno, "failed to read %s", group_path);
>> + return -errno;
>> + }
>> + return groupid;
>> +}
>> +
>> +int vfio_attach_device(char *name, VFIODevice *vbasedev,
>> + AddressSpace *as, Error **errp)
>> +{
>> + int groupid = vfio_device_groupid(vbasedev, errp);
>> + VFIODevice *vbasedev_iter;
>> + VFIOGroup *group;
>> + int ret;
>> +
>> + if (groupid < 0) {
>> + return groupid;
>> + }
>> +
>> + trace_vfio_attach_device(vbasedev->name, groupid);
>hum looking at that again, I was confused by the fact we passed the name
>arg in
>
>vfio_attach_device() whereas vbasedev->name was already filled. Looking at pci
>vfio_realize()
>both are sometimes different
>
> if (!qemu_uuid_is_null(&vdev->vf_token)) {
> qemu_uuid_unparse(&vdev->vf_token, uuid);
> name = g_strdup_printf("%s vf_token=%s", vbasedev->name, uuid);
> } else {
> name = g_strdup(vbasedev->name);
> }
>This may be worth a doc comment.
Yes, agree this is confusing. Just want to ask about the doc comment?
Should I create a vfio doc or just a small comment on call site of
vfio_attach_device()?
Thanks
Zhenzhong
- Re: [PATCH v2 02/12] linux-headers: Add iommufd.h, (continued)
- [PATCH v2 03/12] vfio/common: Move IOMMU agnostic helpers to a separate file, Zhenzhong Duan, 2023/09/26
- [PATCH v2 04/12] vfio/common: Introduce vfio_container_add|del_section_window(), Zhenzhong Duan, 2023/09/26
- [PATCH v2 05/12] vfio/common: Extract out vfio_kvm_device_[add/del]_fd, Zhenzhong Duan, 2023/09/26
- [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device, Zhenzhong Duan, 2023/09/26
- Re: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device, Eric Auger, 2023/09/27
- RE: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device, Duan, Zhenzhong, 2023/09/27
- Re: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device, Eric Auger, 2023/09/27
- RE: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device, Duan, Zhenzhong, 2023/09/27
- Re: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device, Eric Auger, 2023/09/27
Re: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device, Cédric Le Goater, 2023/09/27
[PATCH v2 08/12] vfio/ap: Use vfio_[attach/detach]_device, Zhenzhong Duan, 2023/09/26