diff mbox series

[v1,05/22] vfio/common: Extract out vfio_kvm_device_[add/del]_fd

Message ID 20230830103754.36461-6-zhenzhong.duan@intel.com
State New
Headers show
Series vfio: Adopt iommufd | expand

Commit Message

Duan, Zhenzhong Aug. 30, 2023, 10:37 a.m. UTC
...which will be used by both legacy and iommufd backend.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 hw/vfio/common.c              | 44 +++++++++++++++++++++++------------
 include/hw/vfio/vfio-common.h |  3 +++
 2 files changed, 32 insertions(+), 15 deletions(-)

Comments

Eric Auger Sept. 20, 2023, 11:49 a.m. UTC | #1
Hi Zhenzhong,

On 8/30/23 12:37, Zhenzhong Duan wrote:
> ...which will be used by both legacy and iommufd backend.
I prefer genuine sentences in the commit msg. Also you explain what you
do but not why.

suggestion: Introduce two new helpers, vfio_kvm_device_[add/del]_fd
which take as input a file descriptor which can be either a group fd or
a cdev fd. This uses the new KVM_DEV_VFIO_FILE VFIO KVM device group,
which aliases to the legacy KVM_DEV_VFIO_GROUP.

vfio_kvm_device_add/del_group then call those new helpers.



>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  hw/vfio/common.c              | 44 +++++++++++++++++++++++------------
>  include/hw/vfio/vfio-common.h |  3 +++
>  2 files changed, 32 insertions(+), 15 deletions(-)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 67150e4575..949ad6714a 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -1759,17 +1759,17 @@ void vfio_reset_handler(void *opaque)
>      }
>  }
>  
> -static void vfio_kvm_device_add_group(VFIOGroup *group)
> +int vfio_kvm_device_add_fd(int fd)
>  {
>  #ifdef CONFIG_KVM
>      struct kvm_device_attr attr = {
> -        .group = KVM_DEV_VFIO_GROUP,
> -        .attr = KVM_DEV_VFIO_GROUP_ADD,
> -        .addr = (uint64_t)(unsigned long)&group->fd,
> +        .group = KVM_DEV_VFIO_FILE,
> +        .attr = KVM_DEV_VFIO_FILE_ADD,
> +        .addr = (uint64_t)(unsigned long)&fd,
>      };
>  
>      if (!kvm_enabled()) {
> -        return;
> +        return 0;
>      }
>  
>      if (vfio_kvm_device_fd < 0) {
> @@ -1779,37 +1779,51 @@ static void vfio_kvm_device_add_group(VFIOGroup *group)
>  
>          if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
>              error_report("Failed to create KVM VFIO device: %m");
> -            return;
> +            return -ENODEV;
can't you return -errno?
>          }
>  
>          vfio_kvm_device_fd = cd.fd;
>      }
>  
>      if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
> -        error_report("Failed to add group %d to KVM VFIO device: %m",
> -                     group->groupid);
> +        error_report("Failed to add fd %d to KVM VFIO device: %m",
> +                     fd);
> +        return -errno;
>      }
>  #endif
> +    return 0;
>  }
>  
> -static void vfio_kvm_device_del_group(VFIOGroup *group)
> +static void vfio_kvm_device_add_group(VFIOGroup *group)
> +{
> +    vfio_kvm_device_add_fd(group->fd);
Since vfio_kvm_device_add_fd now returns an error value, it's a pity not
to use it and propagate it. Also you could fill an errp with the error
msg and use it in vfio_connect_container(). But this is a new error
handling there.
> +}
> +
> +int vfio_kvm_device_del_fd(int fd)
not sure we want this to return an error. But if we do, I think it would
be nicer to propagate the error up.
>  {
>  #ifdef CONFIG_KVM
>      struct kvm_device_attr attr = {
> -        .group = KVM_DEV_VFIO_GROUP,
> -        .attr = KVM_DEV_VFIO_GROUP_DEL,
> -        .addr = (uint64_t)(unsigned long)&group->fd,
> +        .group = KVM_DEV_VFIO_FILE,
> +        .attr = KVM_DEV_VFIO_FILE_DEL,
> +        .addr = (uint64_t)(unsigned long)&fd,
>      };
>  
>      if (vfio_kvm_device_fd < 0) {
> -        return;
> +        return -EINVAL;
>      }
>  
>      if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
> -        error_report("Failed to remove group %d from KVM VFIO device: %m",
> -                     group->groupid);
> +        error_report("Failed to remove fd %d from KVM VFIO device: %m",
> +                     fd);
> +        return -EBADF;
-errno?
>      }
>  #endif
> +    return 0;
> +}
> +
> +static void vfio_kvm_device_del_group(VFIOGroup *group)
> +{
> +    vfio_kvm_device_del_fd(group->fd);
>  }
>  
>  static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 5e376c436e..598c3ce079 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -220,6 +220,9 @@ 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_kvm_device_add_fd(int fd);
> +int vfio_kvm_device_del_fd(int fd);
> +
>  extern const MemoryRegionOps vfio_region_ops;
>  typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;
>  extern VFIOGroupList vfio_group_list;
Thanks

Eric
Alex Williamson Sept. 20, 2023, 9:39 p.m. UTC | #2
On Wed, 30 Aug 2023 18:37:37 +0800
Zhenzhong Duan <zhenzhong.duan@intel.com> wrote:

> ...which will be used by both legacy and iommufd backend.

+1 to Eric's comments regarding complete sentences in the commit log
and suggested description.

> 
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  hw/vfio/common.c              | 44 +++++++++++++++++++++++------------
>  include/hw/vfio/vfio-common.h |  3 +++
>  2 files changed, 32 insertions(+), 15 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 67150e4575..949ad6714a 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -1759,17 +1759,17 @@ void vfio_reset_handler(void *opaque)
>      }
>  }
>  
> -static void vfio_kvm_device_add_group(VFIOGroup *group)
> +int vfio_kvm_device_add_fd(int fd)

Returning int vs void looks gratuitous, nothing uses the return value
in this series.

>  {
>  #ifdef CONFIG_KVM
>      struct kvm_device_attr attr = {
> -        .group = KVM_DEV_VFIO_GROUP,
> -        .attr = KVM_DEV_VFIO_GROUP_ADD,
> -        .addr = (uint64_t)(unsigned long)&group->fd,
> +        .group = KVM_DEV_VFIO_FILE,
> +        .attr = KVM_DEV_VFIO_FILE_ADD,
> +        .addr = (uint64_t)(unsigned long)&fd,
>      };
>  
>      if (!kvm_enabled()) {
> -        return;
> +        return 0;
>      }
>  
>      if (vfio_kvm_device_fd < 0) {
> @@ -1779,37 +1779,51 @@ static void vfio_kvm_device_add_group(VFIOGroup *group)
>  
>          if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
>              error_report("Failed to create KVM VFIO device: %m");
> -            return;
> +            return -ENODEV;
>          }
>  
>          vfio_kvm_device_fd = cd.fd;
>      }
>  
>      if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
> -        error_report("Failed to add group %d to KVM VFIO device: %m",
> -                     group->groupid);
> +        error_report("Failed to add fd %d to KVM VFIO device: %m",
> +                     fd);

It's not nearly as useful to report an fd# in the error log vs the
group#.  Thanks,

Alex

> +        return -errno;
>      }
>  #endif
> +    return 0;
>  }
>  
> -static void vfio_kvm_device_del_group(VFIOGroup *group)
> +static void vfio_kvm_device_add_group(VFIOGroup *group)
> +{
> +    vfio_kvm_device_add_fd(group->fd);
> +}
> +
> +int vfio_kvm_device_del_fd(int fd)
>  {
>  #ifdef CONFIG_KVM
>      struct kvm_device_attr attr = {
> -        .group = KVM_DEV_VFIO_GROUP,
> -        .attr = KVM_DEV_VFIO_GROUP_DEL,
> -        .addr = (uint64_t)(unsigned long)&group->fd,
> +        .group = KVM_DEV_VFIO_FILE,
> +        .attr = KVM_DEV_VFIO_FILE_DEL,
> +        .addr = (uint64_t)(unsigned long)&fd,
>      };
>  
>      if (vfio_kvm_device_fd < 0) {
> -        return;
> +        return -EINVAL;
>      }
>  
>      if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
> -        error_report("Failed to remove group %d from KVM VFIO device: %m",
> -                     group->groupid);
> +        error_report("Failed to remove fd %d from KVM VFIO device: %m",
> +                     fd);
> +        return -EBADF;
>      }
>  #endif
> +    return 0;
> +}
> +
> +static void vfio_kvm_device_del_group(VFIOGroup *group)
> +{
> +    vfio_kvm_device_del_fd(group->fd);
>  }
>  
>  static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 5e376c436e..598c3ce079 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -220,6 +220,9 @@ 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_kvm_device_add_fd(int fd);
> +int vfio_kvm_device_del_fd(int fd);
> +
>  extern const MemoryRegionOps vfio_region_ops;
>  typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;
>  extern VFIOGroupList vfio_group_list;
Duan, Zhenzhong Sept. 21, 2023, 2:04 a.m. UTC | #3
>-----Original Message-----
>From: Eric Auger <eric.auger@redhat.com>
>Sent: Wednesday, September 20, 2023 7:49 PM
>Subject: Re: [PATCH v1 05/22] vfio/common: Extract out
>vfio_kvm_device_[add/del]_fd
>
>Hi Zhenzhong,
>
>On 8/30/23 12:37, Zhenzhong Duan wrote:
>> ...which will be used by both legacy and iommufd backend.
>I prefer genuine sentences in the commit msg. Also you explain what you
>do but not why.
>
>suggestion: Introduce two new helpers, vfio_kvm_device_[add/del]_fd
>which take as input a file descriptor which can be either a group fd or
>a cdev fd. This uses the new KVM_DEV_VFIO_FILE VFIO KVM device group,
>which aliases to the legacy KVM_DEV_VFIO_GROUP.
>
>vfio_kvm_device_add/del_group then call those new helpers.

Thanks, will update in v2.

>
>
>
>>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>  hw/vfio/common.c              | 44 +++++++++++++++++++++++------------
>>  include/hw/vfio/vfio-common.h |  3 +++
>>  2 files changed, 32 insertions(+), 15 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 67150e4575..949ad6714a 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -1759,17 +1759,17 @@ void vfio_reset_handler(void *opaque)
>>      }
>>  }
>>
>> -static void vfio_kvm_device_add_group(VFIOGroup *group)
>> +int vfio_kvm_device_add_fd(int fd)
>>  {
>>  #ifdef CONFIG_KVM
>>      struct kvm_device_attr attr = {
>> -        .group = KVM_DEV_VFIO_GROUP,
>> -        .attr = KVM_DEV_VFIO_GROUP_ADD,
>> -        .addr = (uint64_t)(unsigned long)&group->fd,
>> +        .group = KVM_DEV_VFIO_FILE,
>> +        .attr = KVM_DEV_VFIO_FILE_ADD,
>> +        .addr = (uint64_t)(unsigned long)&fd,
>>      };
>>
>>      if (!kvm_enabled()) {
>> -        return;
>> +        return 0;
>>      }
>>
>>      if (vfio_kvm_device_fd < 0) {
>> @@ -1779,37 +1779,51 @@ static void
>vfio_kvm_device_add_group(VFIOGroup *group)
>>
>>          if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
>>              error_report("Failed to create KVM VFIO device: %m");
>> -            return;
>> +            return -ENODEV;
>can't you return -errno?
Will fix.

>>          }
>>
>>          vfio_kvm_device_fd = cd.fd;
>>      }
>>
>>      if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
>> -        error_report("Failed to add group %d to KVM VFIO device: %m",
>> -                     group->groupid);
>> +        error_report("Failed to add fd %d to KVM VFIO device: %m",
>> +                     fd);
>> +        return -errno;
>>      }
>>  #endif
>> +    return 0;
>>  }
>>
>> -static void vfio_kvm_device_del_group(VFIOGroup *group)
>> +static void vfio_kvm_device_add_group(VFIOGroup *group)
>> +{
>> +    vfio_kvm_device_add_fd(group->fd);
>Since vfio_kvm_device_add_fd now returns an error value, it's a pity not
>to use it and propagate it. Also you could fill an errp with the error
>msg and use it in vfio_connect_container(). But this is a new error
>handling there.

What about having vfio_kvm_device_add_fd return void as
vfio_kvm_device_add_group. I just realize vfio_connect_container()
doesn't get any failure of vfio_kvm_device_add_group, propagating
err to vfio_connect_container() is just to print it out there which I have
done in vfio_kvm_device_add_fd.

>> +}
>> +
>> +int vfio_kvm_device_del_fd(int fd)
>not sure we want this to return an error. But if we do, I think it would
>be nicer to propagate the error up.

Same question as above.

>>  {
>>  #ifdef CONFIG_KVM
>>      struct kvm_device_attr attr = {
>> -        .group = KVM_DEV_VFIO_GROUP,
>> -        .attr = KVM_DEV_VFIO_GROUP_DEL,
>> -        .addr = (uint64_t)(unsigned long)&group->fd,
>> +        .group = KVM_DEV_VFIO_FILE,
>> +        .attr = KVM_DEV_VFIO_FILE_DEL,
>> +        .addr = (uint64_t)(unsigned long)&fd,
>>      };
>>
>>      if (vfio_kvm_device_fd < 0) {
>> -        return;
>> +        return -EINVAL;
>>      }
>>
>>      if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
>> -        error_report("Failed to remove group %d from KVM VFIO device: %m",
>> -                     group->groupid);
>> +        error_report("Failed to remove fd %d from KVM VFIO device: %m",
>> +                     fd);
>> +        return -EBADF;
>-errno?
Sure.

Thanks
Zhenzhong
Duan, Zhenzhong Sept. 21, 2023, 6:03 a.m. UTC | #4
>-----Original Message-----
>From: Alex Williamson <alex.williamson@redhat.com>
>Sent: Thursday, September 21, 2023 5:40 AM
>Subject: Re: [PATCH v1 05/22] vfio/common: Extract out
>vfio_kvm_device_[add/del]_fd
>
>On Wed, 30 Aug 2023 18:37:37 +0800
>Zhenzhong Duan <zhenzhong.duan@intel.com> wrote:
>
>> ...which will be used by both legacy and iommufd backend.
>
>+1 to Eric's comments regarding complete sentences in the commit log
>and suggested description.

Will fix.

>
>>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>  hw/vfio/common.c              | 44 +++++++++++++++++++++++------------
>>  include/hw/vfio/vfio-common.h |  3 +++
>>  2 files changed, 32 insertions(+), 15 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 67150e4575..949ad6714a 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -1759,17 +1759,17 @@ void vfio_reset_handler(void *opaque)
>>      }
>>  }
>>
>> -static void vfio_kvm_device_add_group(VFIOGroup *group)
>> +int vfio_kvm_device_add_fd(int fd)
>
>Returning int vs void looks gratuitous, nothing uses the return value
>in this series.

Will return void.

>
>>  {
>>  #ifdef CONFIG_KVM
>>      struct kvm_device_attr attr = {
>> -        .group = KVM_DEV_VFIO_GROUP,
>> -        .attr = KVM_DEV_VFIO_GROUP_ADD,
>> -        .addr = (uint64_t)(unsigned long)&group->fd,
>> +        .group = KVM_DEV_VFIO_FILE,
>> +        .attr = KVM_DEV_VFIO_FILE_ADD,
>> +        .addr = (uint64_t)(unsigned long)&fd,
>>      };
>>
>>      if (!kvm_enabled()) {
>> -        return;
>> +        return 0;
>>      }
>>
>>      if (vfio_kvm_device_fd < 0) {
>> @@ -1779,37 +1779,51 @@ static void
>vfio_kvm_device_add_group(VFIOGroup *group)
>>
>>          if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
>>              error_report("Failed to create KVM VFIO device: %m");
>> -            return;
>> +            return -ENODEV;
>>          }
>>
>>          vfio_kvm_device_fd = cd.fd;
>>      }
>>
>>      if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
>> -        error_report("Failed to add group %d to KVM VFIO device: %m",
>> -                     group->groupid);
>> +        error_report("Failed to add fd %d to KVM VFIO device: %m",
>> +                     fd);
>
>It's not nearly as useful to report an fd# in the error log vs the
>group#.  Thanks,

What about checking the return value of vfio_kvm_device_add_fd and
error_report in vfio_kvm_device_add_group. But that will be duplicate
error report. Is that acceptable?

Thanks
Zhenzhong
Cédric Le Goater Sept. 21, 2023, 8:42 a.m. UTC | #5
On 9/20/23 13:49, Eric Auger wrote:
> Hi Zhenzhong,
> 
> On 8/30/23 12:37, Zhenzhong Duan wrote:
>> ...which will be used by both legacy and iommufd backend.
> I prefer genuine sentences in the commit msg. Also you explain what you
> do but not why.
> 
> suggestion: Introduce two new helpers, vfio_kvm_device_[add/del]_fd
> which take as input a file descriptor which can be either a group fd or
> a cdev fd. This uses the new KVM_DEV_VFIO_FILE VFIO KVM device group,
> which aliases to the legacy KVM_DEV_VFIO_GROUP.

Ah yes. I didn't understand why the 's/GROUP/FILE/' change in the
VFIO KVM device ioctls. Thanks for clarifying.

What about pre-6.6 kernels without KVM_DEV_VFIO_FILE support ?

C.


> 
> vfio_kvm_device_add/del_group then call those new helpers.
> 
> 
> 
>>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>   hw/vfio/common.c              | 44 +++++++++++++++++++++++------------
>>   include/hw/vfio/vfio-common.h |  3 +++
>>   2 files changed, 32 insertions(+), 15 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 67150e4575..949ad6714a 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -1759,17 +1759,17 @@ void vfio_reset_handler(void *opaque)
>>       }
>>   }
>>   
>> -static void vfio_kvm_device_add_group(VFIOGroup *group)
>> +int vfio_kvm_device_add_fd(int fd)
>>   {
>>   #ifdef CONFIG_KVM
>>       struct kvm_device_attr attr = {
>> -        .group = KVM_DEV_VFIO_GROUP,
>> -        .attr = KVM_DEV_VFIO_GROUP_ADD,
>> -        .addr = (uint64_t)(unsigned long)&group->fd,
>> +        .group = KVM_DEV_VFIO_FILE,
>> +        .attr = KVM_DEV_VFIO_FILE_ADD,
>> +        .addr = (uint64_t)(unsigned long)&fd,
>>       };
>>   
>>       if (!kvm_enabled()) {
>> -        return;
>> +        return 0;
>>       }
>>   
>>       if (vfio_kvm_device_fd < 0) {
>> @@ -1779,37 +1779,51 @@ static void vfio_kvm_device_add_group(VFIOGroup *group)
>>   
>>           if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
>>               error_report("Failed to create KVM VFIO device: %m");
>> -            return;
>> +            return -ENODEV;
> can't you return -errno?
>>           }
>>   
>>           vfio_kvm_device_fd = cd.fd;
>>       }
>>   
>>       if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
>> -        error_report("Failed to add group %d to KVM VFIO device: %m",
>> -                     group->groupid);
>> +        error_report("Failed to add fd %d to KVM VFIO device: %m",
>> +                     fd);
>> +        return -errno;
>>       }
>>   #endif
>> +    return 0;
>>   }
>>   
>> -static void vfio_kvm_device_del_group(VFIOGroup *group)
>> +static void vfio_kvm_device_add_group(VFIOGroup *group)
>> +{
>> +    vfio_kvm_device_add_fd(group->fd);
> Since vfio_kvm_device_add_fd now returns an error value, it's a pity not
> to use it and propagate it. Also you could fill an errp with the error
> msg and use it in vfio_connect_container(). But this is a new error
> handling there.
>> +}
>> +
>> +int vfio_kvm_device_del_fd(int fd)
> not sure we want this to return an error. But if we do, I think it would
> be nicer to propagate the error up.
>>   {
>>   #ifdef CONFIG_KVM
>>       struct kvm_device_attr attr = {
>> -        .group = KVM_DEV_VFIO_GROUP,
>> -        .attr = KVM_DEV_VFIO_GROUP_DEL,
>> -        .addr = (uint64_t)(unsigned long)&group->fd,
>> +        .group = KVM_DEV_VFIO_FILE,
>> +        .attr = KVM_DEV_VFIO_FILE_DEL,
>> +        .addr = (uint64_t)(unsigned long)&fd,
>>       };
>>   
>>       if (vfio_kvm_device_fd < 0) {
>> -        return;
>> +        return -EINVAL;
>>       }
>>   
>>       if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
>> -        error_report("Failed to remove group %d from KVM VFIO device: %m",
>> -                     group->groupid);
>> +        error_report("Failed to remove fd %d from KVM VFIO device: %m",
>> +                     fd);
>> +        return -EBADF;
> -errno?
>>       }
>>   #endif
>> +    return 0;
>> +}
>> +
>> +static void vfio_kvm_device_del_group(VFIOGroup *group)
>> +{
>> +    vfio_kvm_device_del_fd(group->fd);
>>   }
>>   
>>   static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)
>> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
>> index 5e376c436e..598c3ce079 100644
>> --- a/include/hw/vfio/vfio-common.h
>> +++ b/include/hw/vfio/vfio-common.h
>> @@ -220,6 +220,9 @@ 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_kvm_device_add_fd(int fd);
>> +int vfio_kvm_device_del_fd(int fd);
>> +
>>   extern const MemoryRegionOps vfio_region_ops;
>>   typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;
>>   extern VFIOGroupList vfio_group_list;
> Thanks
> 
> Eric
>
Duan, Zhenzhong Sept. 21, 2023, 10:22 a.m. UTC | #6
>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Sent: Thursday, September 21, 2023 4:42 PM
>Subject: Re: [PATCH v1 05/22] vfio/common: Extract out
>vfio_kvm_device_[add/del]_fd
>
>On 9/20/23 13:49, Eric Auger wrote:
>> Hi Zhenzhong,
>>
>> On 8/30/23 12:37, Zhenzhong Duan wrote:
>>> ...which will be used by both legacy and iommufd backend.
>> I prefer genuine sentences in the commit msg. Also you explain what you
>> do but not why.
>>
>> suggestion: Introduce two new helpers, vfio_kvm_device_[add/del]_fd
>> which take as input a file descriptor which can be either a group fd or
>> a cdev fd. This uses the new KVM_DEV_VFIO_FILE VFIO KVM device group,
>> which aliases to the legacy KVM_DEV_VFIO_GROUP.
>
>Ah yes. I didn't understand why the 's/GROUP/FILE/' change in the
>VFIO KVM device ioctls. Thanks for clarifying.
>
>What about pre-6.6 kernels without KVM_DEV_VFIO_FILE support ?
They are purely alias. See below commit:

commit da3c22c74a3c6cbd26df40b2f6798a2d41be80ac
Author: Thomas Huth <thuth@redhat.com>
Date:   Tue Sep 12 11:24:40 2023 +0200

    linux-headers: Update to Linux v6.6-rc1

    This update contains the required header changes for the
    "target/s390x: AP-passthrough for PV guests" patch from
    Steffen Eiden.

    Message-ID: <20230912093432.180041-1-thuth@redhat.com>
    Signed-off-by: Thomas Huth <thuth@redhat.com>

diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index 1f3f3333a4..0d74ee999a 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -1414,9 +1414,16 @@ struct kvm_device_attr {
        __u64   addr;           /* userspace address of attr data */
 };

-#define  KVM_DEV_VFIO_GROUP                    1
-#define   KVM_DEV_VFIO_GROUP_ADD                       1
-#define   KVM_DEV_VFIO_GROUP_DEL                       2
+#define  KVM_DEV_VFIO_FILE                     1
+
+#define   KVM_DEV_VFIO_FILE_ADD                        1
+#define   KVM_DEV_VFIO_FILE_DEL                        2
+
+/* KVM_DEV_VFIO_GROUP aliases are for compile time uapi compatibility */
+#define  KVM_DEV_VFIO_GROUP    KVM_DEV_VFIO_FILE
+
+#define   KVM_DEV_VFIO_GROUP_ADD       KVM_DEV_VFIO_FILE_ADD
+#define   KVM_DEV_VFIO_GROUP_DEL       KVM_DEV_VFIO_FILE_DEL
 #define   KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE             3

Pre-6.6 kernel not supporting KVM_DEV_VFIO_FILE also not support IOMMUFD.
So I think that's fine.

Thanks
Zhenzhong
Cédric Le Goater Sept. 21, 2023, 10:53 a.m. UTC | #7
On 9/21/23 12:22, Duan, Zhenzhong wrote:
> 
> 
>> -----Original Message-----
>> From: Cédric Le Goater <clg@redhat.com>
>> Sent: Thursday, September 21, 2023 4:42 PM
>> Subject: Re: [PATCH v1 05/22] vfio/common: Extract out
>> vfio_kvm_device_[add/del]_fd
>>
>> On 9/20/23 13:49, Eric Auger wrote:
>>> Hi Zhenzhong,
>>>
>>> On 8/30/23 12:37, Zhenzhong Duan wrote:
>>>> ...which will be used by both legacy and iommufd backend.
>>> I prefer genuine sentences in the commit msg. Also you explain what you
>>> do but not why.
>>>
>>> suggestion: Introduce two new helpers, vfio_kvm_device_[add/del]_fd
>>> which take as input a file descriptor which can be either a group fd or
>>> a cdev fd. This uses the new KVM_DEV_VFIO_FILE VFIO KVM device group,
>>> which aliases to the legacy KVM_DEV_VFIO_GROUP.
>>
>> Ah yes. I didn't understand why the 's/GROUP/FILE/' change in the
>> VFIO KVM device ioctls. Thanks for clarifying.
>>
>> What about pre-6.6 kernels without KVM_DEV_VFIO_FILE support ?
> They are purely alias. See below commit:

Ah. I missed that. thanks again.

C.
diff mbox series

Patch

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 67150e4575..949ad6714a 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1759,17 +1759,17 @@  void vfio_reset_handler(void *opaque)
     }
 }
 
-static void vfio_kvm_device_add_group(VFIOGroup *group)
+int vfio_kvm_device_add_fd(int fd)
 {
 #ifdef CONFIG_KVM
     struct kvm_device_attr attr = {
-        .group = KVM_DEV_VFIO_GROUP,
-        .attr = KVM_DEV_VFIO_GROUP_ADD,
-        .addr = (uint64_t)(unsigned long)&group->fd,
+        .group = KVM_DEV_VFIO_FILE,
+        .attr = KVM_DEV_VFIO_FILE_ADD,
+        .addr = (uint64_t)(unsigned long)&fd,
     };
 
     if (!kvm_enabled()) {
-        return;
+        return 0;
     }
 
     if (vfio_kvm_device_fd < 0) {
@@ -1779,37 +1779,51 @@  static void vfio_kvm_device_add_group(VFIOGroup *group)
 
         if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
             error_report("Failed to create KVM VFIO device: %m");
-            return;
+            return -ENODEV;
         }
 
         vfio_kvm_device_fd = cd.fd;
     }
 
     if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
-        error_report("Failed to add group %d to KVM VFIO device: %m",
-                     group->groupid);
+        error_report("Failed to add fd %d to KVM VFIO device: %m",
+                     fd);
+        return -errno;
     }
 #endif
+    return 0;
 }
 
-static void vfio_kvm_device_del_group(VFIOGroup *group)
+static void vfio_kvm_device_add_group(VFIOGroup *group)
+{
+    vfio_kvm_device_add_fd(group->fd);
+}
+
+int vfio_kvm_device_del_fd(int fd)
 {
 #ifdef CONFIG_KVM
     struct kvm_device_attr attr = {
-        .group = KVM_DEV_VFIO_GROUP,
-        .attr = KVM_DEV_VFIO_GROUP_DEL,
-        .addr = (uint64_t)(unsigned long)&group->fd,
+        .group = KVM_DEV_VFIO_FILE,
+        .attr = KVM_DEV_VFIO_FILE_DEL,
+        .addr = (uint64_t)(unsigned long)&fd,
     };
 
     if (vfio_kvm_device_fd < 0) {
-        return;
+        return -EINVAL;
     }
 
     if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
-        error_report("Failed to remove group %d from KVM VFIO device: %m",
-                     group->groupid);
+        error_report("Failed to remove fd %d from KVM VFIO device: %m",
+                     fd);
+        return -EBADF;
     }
 #endif
+    return 0;
+}
+
+static void vfio_kvm_device_del_group(VFIOGroup *group)
+{
+    vfio_kvm_device_del_fd(group->fd);
 }
 
 static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 5e376c436e..598c3ce079 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -220,6 +220,9 @@  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_kvm_device_add_fd(int fd);
+int vfio_kvm_device_del_fd(int fd);
+
 extern const MemoryRegionOps vfio_region_ops;
 typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;
 extern VFIOGroupList vfio_group_list;