2024-01-24 17:28:40

by Suzuki K Poulose

[permalink] [raw]
Subject: [PATCH] virtio: uapi: Drop __packed attribute in linux/virtio_pci.h:

Commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
added "__packed" structures to UAPI header linux/virtio_pci.h. This triggers
build failures in the consumer userspace applications without proper "definition"
of __packed (e.g., kvmtool build fails).

Moreover, the structures are already packed well, and doesn't need explicit
packing, similar to the rest of the structures in all virtio_* headers. Remove
the __packed attribute.

Fixes: commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
Cc: Feng Liu <[email protected]>
Cc: Michael S. Tsirkin <[email protected]>
Cc: Yishai Hadas <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Jean-Philippe Brucker <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
---
include/uapi/linux/virtio_pci.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index ef3810dee7ef..a8208492e822 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -240,7 +240,7 @@ struct virtio_pci_cfg_cap {
#define VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ 0x5
#define VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO 0x6

-struct __packed virtio_admin_cmd_hdr {
+struct virtio_admin_cmd_hdr {
__le16 opcode;
/*
* 1 - SR-IOV
@@ -252,20 +252,20 @@ struct __packed virtio_admin_cmd_hdr {
__le64 group_member_id;
};

-struct __packed virtio_admin_cmd_status {
+struct virtio_admin_cmd_status {
__le16 status;
__le16 status_qualifier;
/* Unused, reserved for future extensions. */
__u8 reserved2[4];
};

-struct __packed virtio_admin_cmd_legacy_wr_data {
+struct virtio_admin_cmd_legacy_wr_data {
__u8 offset; /* Starting offset of the register(s) to write. */
__u8 reserved[7];
__u8 registers[];
};

-struct __packed virtio_admin_cmd_legacy_rd_data {
+struct virtio_admin_cmd_legacy_rd_data {
__u8 offset; /* Starting offset of the register(s) to read. */
};

@@ -275,7 +275,7 @@ struct __packed virtio_admin_cmd_legacy_rd_data {

#define VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO 4

-struct __packed virtio_admin_cmd_notify_info_data {
+struct virtio_admin_cmd_notify_info_data {
__u8 flags; /* 0 = end of list, 1 = owner device, 2 = member device */
__u8 bar; /* BAR of the member or the owner device */
__u8 padding[6];
--
2.34.1



2024-01-24 18:22:29

by Jean-Philippe Brucker

[permalink] [raw]
Subject: Re: [PATCH] virtio: uapi: Drop __packed attribute in linux/virtio_pci.h:

On Wed, Jan 24, 2024 at 05:23:45PM +0000, Suzuki K Poulose wrote:
> Commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
> added "__packed" structures to UAPI header linux/virtio_pci.h. This triggers
> build failures in the consumer userspace applications without proper "definition"
> of __packed (e.g., kvmtool build fails).
>
> Moreover, the structures are already packed well, and doesn't need explicit
> packing, similar to the rest of the structures in all virtio_* headers. Remove
> the __packed attribute.
>
> Fixes: commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
> Cc: Feng Liu <[email protected]>
> Cc: Michael S. Tsirkin <[email protected]>
> Cc: Yishai Hadas <[email protected]>
> Cc: Alex Williamson <[email protected]>
> Cc: Jean-Philippe Brucker <[email protected]>
> Signed-off-by: Suzuki K Poulose <[email protected]>

Reviewed-by: Jean-Philippe Brucker <[email protected]>

> ---
> include/uapi/linux/virtio_pci.h | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index ef3810dee7ef..a8208492e822 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -240,7 +240,7 @@ struct virtio_pci_cfg_cap {
> #define VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ 0x5
> #define VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO 0x6
>
> -struct __packed virtio_admin_cmd_hdr {
> +struct virtio_admin_cmd_hdr {
> __le16 opcode;
> /*
> * 1 - SR-IOV
> @@ -252,20 +252,20 @@ struct __packed virtio_admin_cmd_hdr {
> __le64 group_member_id;
> };
>
> -struct __packed virtio_admin_cmd_status {
> +struct virtio_admin_cmd_status {
> __le16 status;
> __le16 status_qualifier;
> /* Unused, reserved for future extensions. */
> __u8 reserved2[4];
> };
>
> -struct __packed virtio_admin_cmd_legacy_wr_data {
> +struct virtio_admin_cmd_legacy_wr_data {
> __u8 offset; /* Starting offset of the register(s) to write. */
> __u8 reserved[7];
> __u8 registers[];
> };
>
> -struct __packed virtio_admin_cmd_legacy_rd_data {
> +struct virtio_admin_cmd_legacy_rd_data {
> __u8 offset; /* Starting offset of the register(s) to read. */
> };
>
> @@ -275,7 +275,7 @@ struct __packed virtio_admin_cmd_legacy_rd_data {
>
> #define VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO 4
>
> -struct __packed virtio_admin_cmd_notify_info_data {
> +struct virtio_admin_cmd_notify_info_data {
> __u8 flags; /* 0 = end of list, 1 = owner device, 2 = member device */
> __u8 bar; /* BAR of the member or the owner device */
> __u8 padding[6];
> --
> 2.34.1
>

2024-01-25 22:58:47

by Michael S. Tsirkin

[permalink] [raw]
Subject: Re: [PATCH] virtio: uapi: Drop __packed attribute in linux/virtio_pci.h:

On Wed, Jan 24, 2024 at 05:23:45PM +0000, Suzuki K Poulose wrote:
> Commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
> added "__packed" structures to UAPI header linux/virtio_pci.h. This triggers
> build failures in the consumer userspace applications without proper "definition"
> of __packed (e.g., kvmtool build fails).
>
> Moreover, the structures are already packed well, and doesn't need explicit
> packing, similar to the rest of the structures in all virtio_* headers. Remove
> the __packed attribute.
>
> Fixes: commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")


Proper form is:

Fixes: 92792ac752aa ("virtio-pci: Introduce admin command sending function")

> Cc: Feng Liu <[email protected]>
> Cc: Michael S. Tsirkin <[email protected]>
> Cc: Yishai Hadas <[email protected]>
> Cc: Alex Williamson <[email protected]>
> Cc: Jean-Philippe Brucker <[email protected]>
> Signed-off-by: Suzuki K Poulose <[email protected]>
> ---
> include/uapi/linux/virtio_pci.h | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index ef3810dee7ef..a8208492e822 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -240,7 +240,7 @@ struct virtio_pci_cfg_cap {
> #define VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ 0x5
> #define VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO 0x6
>
> -struct __packed virtio_admin_cmd_hdr {
> +struct virtio_admin_cmd_hdr {
> __le16 opcode;
> /*
> * 1 - SR-IOV
> @@ -252,20 +252,20 @@ struct __packed virtio_admin_cmd_hdr {
> __le64 group_member_id;
> };
>
> -struct __packed virtio_admin_cmd_status {
> +struct virtio_admin_cmd_status {
> __le16 status;
> __le16 status_qualifier;
> /* Unused, reserved for future extensions. */
> __u8 reserved2[4];
> };
>
> -struct __packed virtio_admin_cmd_legacy_wr_data {
> +struct virtio_admin_cmd_legacy_wr_data {
> __u8 offset; /* Starting offset of the register(s) to write. */
> __u8 reserved[7];
> __u8 registers[];
> };
>
> -struct __packed virtio_admin_cmd_legacy_rd_data {
> +struct virtio_admin_cmd_legacy_rd_data {
> __u8 offset; /* Starting offset of the register(s) to read. */
> };
>
> @@ -275,7 +275,7 @@ struct __packed virtio_admin_cmd_legacy_rd_data {
>
> #define VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO 4
>
> -struct __packed virtio_admin_cmd_notify_info_data {
> +struct virtio_admin_cmd_notify_info_data {
> __u8 flags; /* 0 = end of list, 1 = owner device, 2 = member device */
> __u8 bar; /* BAR of the member or the owner device */
> __u8 padding[6];


Acked-by: Michael S. Tsirkin <[email protected]>

I will queue this.

> --
> 2.34.1


2024-01-25 23:17:44

by Suzuki K Poulose

[permalink] [raw]
Subject: Re: [PATCH] virtio: uapi: Drop __packed attribute in linux/virtio_pci.h:

On 25/01/2024 22:48, Michael S. Tsirkin wrote:
> On Wed, Jan 24, 2024 at 05:23:45PM +0000, Suzuki K Poulose wrote:
>> Commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
>> added "__packed" structures to UAPI header linux/virtio_pci.h. This triggers
>> build failures in the consumer userspace applications without proper "definition"
>> of __packed (e.g., kvmtool build fails).
>>
>> Moreover, the structures are already packed well, and doesn't need explicit
>> packing, similar to the rest of the structures in all virtio_* headers. Remove
>> the __packed attribute.
>>
>> Fixes: commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
>
>
> Proper form is:
>
> Fixes: 92792ac752aa ("virtio-pci: Introduce admin command sending function")

Apologies, for messing that up.

>
>> Cc: Feng Liu <[email protected]>
>> Cc: Michael S. Tsirkin <[email protected]>
>> Cc: Yishai Hadas <[email protected]>
>> Cc: Alex Williamson <[email protected]>
>> Cc: Jean-Philippe Brucker <[email protected]>
>> Signed-off-by: Suzuki K Poulose <[email protected]>
>> ---
>> include/uapi/linux/virtio_pci.h | 10 +++++-----
>> 1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
>> index ef3810dee7ef..a8208492e822 100644
>> --- a/include/uapi/linux/virtio_pci.h
>> +++ b/include/uapi/linux/virtio_pci.h
>> @@ -240,7 +240,7 @@ struct virtio_pci_cfg_cap {
>> #define VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ 0x5
>> #define VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO 0x6
>>
>> -struct __packed virtio_admin_cmd_hdr {
>> +struct virtio_admin_cmd_hdr {
>> __le16 opcode;
>> /*
>> * 1 - SR-IOV
>> @@ -252,20 +252,20 @@ struct __packed virtio_admin_cmd_hdr {
>> __le64 group_member_id;
>> };
>>
>> -struct __packed virtio_admin_cmd_status {
>> +struct virtio_admin_cmd_status {
>> __le16 status;
>> __le16 status_qualifier;
>> /* Unused, reserved for future extensions. */
>> __u8 reserved2[4];
>> };
>>
>> -struct __packed virtio_admin_cmd_legacy_wr_data {
>> +struct virtio_admin_cmd_legacy_wr_data {
>> __u8 offset; /* Starting offset of the register(s) to write. */
>> __u8 reserved[7];
>> __u8 registers[];
>> };
>>
>> -struct __packed virtio_admin_cmd_legacy_rd_data {
>> +struct virtio_admin_cmd_legacy_rd_data {
>> __u8 offset; /* Starting offset of the register(s) to read. */
>> };
>>
>> @@ -275,7 +275,7 @@ struct __packed virtio_admin_cmd_legacy_rd_data {
>>
>> #define VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO 4
>>
>> -struct __packed virtio_admin_cmd_notify_info_data {
>> +struct virtio_admin_cmd_notify_info_data {
>> __u8 flags; /* 0 = end of list, 1 = owner device, 2 = member device */
>> __u8 bar; /* BAR of the member or the owner device */
>> __u8 padding[6];
>
>
> Acked-by: Michael S. Tsirkin <[email protected]>
>
> I will queue this.

Thanks
Suzuki

>
>> --
>> 2.34.1
>


2024-01-25 23:18:37

by Michael S. Tsirkin

[permalink] [raw]
Subject: Re: [PATCH] virtio: uapi: Drop __packed attribute in linux/virtio_pci.h:

On Thu, Jan 25, 2024 at 11:10:16PM +0000, Suzuki K Poulose wrote:
> On 25/01/2024 22:48, Michael S. Tsirkin wrote:
> > On Wed, Jan 24, 2024 at 05:23:45PM +0000, Suzuki K Poulose wrote:
> > > Commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
> > > added "__packed" structures to UAPI header linux/virtio_pci.h. This triggers
> > > build failures in the consumer userspace applications without proper "definition"
> > > of __packed (e.g., kvmtool build fails).
> > >
> > > Moreover, the structures are already packed well, and doesn't need explicit
> > > packing, similar to the rest of the structures in all virtio_* headers. Remove
> > > the __packed attribute.
> > >
> > > Fixes: commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
> >
> >
> > Proper form is:
> >
> > Fixes: 92792ac752aa ("virtio-pci: Introduce admin command sending function")
>
> Apologies, for messing that up.


Pls repost a fixed one.

> >
> > > Cc: Feng Liu <[email protected]>
> > > Cc: Michael S. Tsirkin <[email protected]>
> > > Cc: Yishai Hadas <[email protected]>
> > > Cc: Alex Williamson <[email protected]>
> > > Cc: Jean-Philippe Brucker <[email protected]>
> > > Signed-off-by: Suzuki K Poulose <[email protected]>
> > > ---
> > > include/uapi/linux/virtio_pci.h | 10 +++++-----
> > > 1 file changed, 5 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> > > index ef3810dee7ef..a8208492e822 100644
> > > --- a/include/uapi/linux/virtio_pci.h
> > > +++ b/include/uapi/linux/virtio_pci.h
> > > @@ -240,7 +240,7 @@ struct virtio_pci_cfg_cap {
> > > #define VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ 0x5
> > > #define VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO 0x6
> > > -struct __packed virtio_admin_cmd_hdr {
> > > +struct virtio_admin_cmd_hdr {
> > > __le16 opcode;
> > > /*
> > > * 1 - SR-IOV
> > > @@ -252,20 +252,20 @@ struct __packed virtio_admin_cmd_hdr {
> > > __le64 group_member_id;
> > > };
> > > -struct __packed virtio_admin_cmd_status {
> > > +struct virtio_admin_cmd_status {
> > > __le16 status;
> > > __le16 status_qualifier;
> > > /* Unused, reserved for future extensions. */
> > > __u8 reserved2[4];
> > > };
> > > -struct __packed virtio_admin_cmd_legacy_wr_data {
> > > +struct virtio_admin_cmd_legacy_wr_data {
> > > __u8 offset; /* Starting offset of the register(s) to write. */
> > > __u8 reserved[7];
> > > __u8 registers[];
> > > };
> > > -struct __packed virtio_admin_cmd_legacy_rd_data {
> > > +struct virtio_admin_cmd_legacy_rd_data {
> > > __u8 offset; /* Starting offset of the register(s) to read. */
> > > };
> > > @@ -275,7 +275,7 @@ struct __packed virtio_admin_cmd_legacy_rd_data {
> > > #define VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO 4
> > > -struct __packed virtio_admin_cmd_notify_info_data {
> > > +struct virtio_admin_cmd_notify_info_data {
> > > __u8 flags; /* 0 = end of list, 1 = owner device, 2 = member device */
> > > __u8 bar; /* BAR of the member or the owner device */
> > > __u8 padding[6];
> >
> >
> > Acked-by: Michael S. Tsirkin <[email protected]>
> >
> > I will queue this.
>
> Thanks
> Suzuki
>
> >
> > > --
> > > 2.34.1
> >


2024-01-25 23:22:08

by Suzuki K Poulose

[permalink] [raw]
Subject: [PATCH v2] virtio: uapi: Drop __packed attribute in linux/virtio_pci.h

Commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
added "__packed" structures to UAPI header linux/virtio_pci.h. This triggers
build failures in the consumer userspace applications without proper "definition"
of __packed (e.g., kvmtool build fails).

Moreover, the structures are already packed well, and doesn't need explicit
packing, similar to the rest of the structures in all virtio_* headers. Remove
the __packed attribute.

Fixes: 92792ac752aa ("virtio-pci: Introduce admin command sending function")
Cc: Feng Liu <[email protected]>
Cc: Michael S. Tsirkin <[email protected]>
Cc: Yishai Hadas <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Jean-Philippe Brucker <[email protected]>
Reviewed-by: Jean-Philippe Brucker <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
---

Changes since v1:
- Fix description for the "Fixes" tag format
- Collect Tags from Jean-Philippe and Michael

---
include/uapi/linux/virtio_pci.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index ef3810dee7ef..a8208492e822 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -240,7 +240,7 @@ struct virtio_pci_cfg_cap {
#define VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ 0x5
#define VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO 0x6

-struct __packed virtio_admin_cmd_hdr {
+struct virtio_admin_cmd_hdr {
__le16 opcode;
/*
* 1 - SR-IOV
@@ -252,20 +252,20 @@ struct __packed virtio_admin_cmd_hdr {
__le64 group_member_id;
};

-struct __packed virtio_admin_cmd_status {
+struct virtio_admin_cmd_status {
__le16 status;
__le16 status_qualifier;
/* Unused, reserved for future extensions. */
__u8 reserved2[4];
};

-struct __packed virtio_admin_cmd_legacy_wr_data {
+struct virtio_admin_cmd_legacy_wr_data {
__u8 offset; /* Starting offset of the register(s) to write. */
__u8 reserved[7];
__u8 registers[];
};

-struct __packed virtio_admin_cmd_legacy_rd_data {
+struct virtio_admin_cmd_legacy_rd_data {
__u8 offset; /* Starting offset of the register(s) to read. */
};

@@ -275,7 +275,7 @@ struct __packed virtio_admin_cmd_legacy_rd_data {

#define VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO 4

-struct __packed virtio_admin_cmd_notify_info_data {
+struct virtio_admin_cmd_notify_info_data {
__u8 flags; /* 0 = end of list, 1 = owner device, 2 = member device */
__u8 bar; /* BAR of the member or the owner device */
__u8 padding[6];
--
2.34.1


2024-02-01 16:06:18

by Suzuki K Poulose

[permalink] [raw]
Subject: Re: [PATCH v2] virtio: uapi: Drop __packed attribute in linux/virtio_pci.h

On 25/01/2024 23:20, Suzuki K Poulose wrote:
> Commit 92792ac752aa ("virtio-pci: Introduce admin command sending function")
> added "__packed" structures to UAPI header linux/virtio_pci.h. This triggers
> build failures in the consumer userspace applications without proper "definition"
> of __packed (e.g., kvmtool build fails).
>
> Moreover, the structures are already packed well, and doesn't need explicit
> packing, similar to the rest of the structures in all virtio_* headers. Remove
> the __packed attribute.
>
> Fixes: 92792ac752aa ("virtio-pci: Introduce admin command sending function")
> Cc: Feng Liu <[email protected]>
> Cc: Michael S. Tsirkin <[email protected]>
> Cc: Yishai Hadas <[email protected]>
> Cc: Alex Williamson <[email protected]>
> Cc: Jean-Philippe Brucker <[email protected]>
> Reviewed-by: Jean-Philippe Brucker <[email protected]>
> Acked-by: Michael S. Tsirkin <[email protected]>
> Signed-off-by: Suzuki K Poulose <[email protected]>
> ---

Gentle ping.

Suzuki


>
> Changes since v1:
> - Fix description for the "Fixes" tag format
> - Collect Tags from Jean-Philippe and Michael
>
> ---
> include/uapi/linux/virtio_pci.h | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index ef3810dee7ef..a8208492e822 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -240,7 +240,7 @@ struct virtio_pci_cfg_cap {
> #define VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ 0x5
> #define VIRTIO_ADMIN_CMD_LEGACY_NOTIFY_INFO 0x6
>
> -struct __packed virtio_admin_cmd_hdr {
> +struct virtio_admin_cmd_hdr {
> __le16 opcode;
> /*
> * 1 - SR-IOV
> @@ -252,20 +252,20 @@ struct __packed virtio_admin_cmd_hdr {
> __le64 group_member_id;
> };
>
> -struct __packed virtio_admin_cmd_status {
> +struct virtio_admin_cmd_status {
> __le16 status;
> __le16 status_qualifier;
> /* Unused, reserved for future extensions. */
> __u8 reserved2[4];
> };
>
> -struct __packed virtio_admin_cmd_legacy_wr_data {
> +struct virtio_admin_cmd_legacy_wr_data {
> __u8 offset; /* Starting offset of the register(s) to write. */
> __u8 reserved[7];
> __u8 registers[];
> };
>
> -struct __packed virtio_admin_cmd_legacy_rd_data {
> +struct virtio_admin_cmd_legacy_rd_data {
> __u8 offset; /* Starting offset of the register(s) to read. */
> };
>
> @@ -275,7 +275,7 @@ struct __packed virtio_admin_cmd_legacy_rd_data {
>
> #define VIRTIO_ADMIN_CMD_MAX_NOTIFY_INFO 4
>
> -struct __packed virtio_admin_cmd_notify_info_data {
> +struct virtio_admin_cmd_notify_info_data {
> __u8 flags; /* 0 = end of list, 1 = owner device, 2 = member device */
> __u8 bar; /* BAR of the member or the owner device */
> __u8 padding[6];