2022-10-07 13:04:58

by Michael S. Tsirkin

[permalink] [raw]
Subject: Re: [PATCH] virtio_bt: Fix alignment in configuration struct

On Mon, Aug 08, 2022 at 02:04:43PM +0200, Igor Skalkin wrote:
> On 8/8/22 01:00, Michael S. Tsirkin wrote:
>
> On Mon, Aug 08, 2022 at 12:11:52AM +0200, Igor Skalkin wrote:
>
> According to specification [1], "For the device-specific configuration
> space, the driver MUST use 8 bit wide accesses for 8 bit wide fields,
> 16 bit wide and aligned accesses for 16 bit wide fields and 32 bit wide
> and aligned accesses for 32 and 64 bit wide fields.".
>
> Current version of the configuration structure:
>
> struct virtio_bt_config {
> __u8 type;
> __u16 vendor;
> __u16 msft_opcode;
> } __attribute__((packed));
>
> has both 16bit fields non-aligned.
>
> This commit fixes it.
>
> [1] https://ddec1-0-en-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fdocs.oasis%2dopen.org%2fvirtio%2fvirtio%2fv1.1%2fvirtio%2dv1.1.pdf&umid=d1786ace-e8ea-40e8-9665-96c0949174e5&auth=53c7c7de28b92dfd96e93d9dd61a23e634d2fbec-39b15885ceebe9fda9357320aec1ccbac416a470
>
> Signed-off-by: Igor Skalkin <[email protected]>
>
> This is all true enough, but the problem is
> 1. changing uapi like this can't be done, will break userspace
> 2. the driver has more issues and no one seems to want to
> maintain it.
> I posted a patch "Bluetooth: virtio_bt: mark broken" and intend
> to merge it for this release.
>
> This is very sad. We already use this driver in our projects.

Ping. If we still have no maintainer I'm marking it broken, users
should at least be warned.


> Our virtio bluetooth device has two backends - HCI_USER socket backend for one
> platform and uart backend for the other, and works well (after applying your
> "[PATCH] Bluetooth: virtio_bt: fix device remove") patch, so this "device
> removal" problem can probably be considered solved .
> We could help with the rest of the problems you listed that can be solved
> (specification, QEMU support).
> And the only problem that is difficult to solve (because of the need to change
> UAPI header files) is just this one with unaligned configuration fields.
> At the moment, it does not reproduce, because without VIRTIO_BT_F_VND_HCI
> (Indicates vendor command support) feature negotiated, the driver does not
> read the non-aligned configuration fields.
>
> So, what would you advise us to do? Continuing to use the "marked broken"
> driver, start writing a specification for a new from scratch, better one?
> Or is there any way to bring this one back to life?
>
>
>
> ---
> include/uapi/linux/virtio_bt.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/virtio_bt.h b/include/uapi/linux/virtio_bt.h
> index a7bd48daa9a9..adc03709cc4f 100644
> --- a/include/uapi/linux/virtio_bt.h
> +++ b/include/uapi/linux/virtio_bt.h
> @@ -23,9 +23,9 @@ enum virtio_bt_config_vendor {
> };
>
> struct virtio_bt_config {
> - __u8 type;
> __u16 vendor;
> __u16 msft_opcode;
> + __u8 type;
> } __attribute__((packed));
>
> #endif /* _UAPI_LINUX_VIRTIO_BT_H */
> --
> 2.34.1
>
> --
>
> Best regards,
>
> Igor Skalkin
> Software Engineer
>
> OpenSynergy GmbH
> Rotherstr. 20, 10245 Berlin
>
> [email protected]
> http://www.opensynergy.com
>
> registered: Amtsgericht Charlottenburg, HRB 108616B
> General Management: Rolf Morich, Stefaan Sonck Thiebaut
>
>
> Please mind our privacy notice pursuant to Art. 13 GDPR. // Unsere Hinweise zum
> Datenschutz gem. Art. 13 DSGVO finden Sie hier.


2022-10-07 19:37:22

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: Re: [PATCH] virtio_bt: Fix alignment in configuration struct

Hi Michael,

On Fri, Oct 7, 2022 at 6:03 AM Michael S. Tsirkin <[email protected]> wrote:
>
> On Mon, Aug 08, 2022 at 02:04:43PM +0200, Igor Skalkin wrote:
> > On 8/8/22 01:00, Michael S. Tsirkin wrote:
> >
> > On Mon, Aug 08, 2022 at 12:11:52AM +0200, Igor Skalkin wrote:
> >
> > According to specification [1], "For the device-specific configuration
> > space, the driver MUST use 8 bit wide accesses for 8 bit wide fields,
> > 16 bit wide and aligned accesses for 16 bit wide fields and 32 bit wide
> > and aligned accesses for 32 and 64 bit wide fields.".
> >
> > Current version of the configuration structure:
> >
> > struct virtio_bt_config {
> > __u8 type;
> > __u16 vendor;
> > __u16 msft_opcode;
> > } __attribute__((packed));
> >
> > has both 16bit fields non-aligned.
> >
> > This commit fixes it.
> >
> > [1] https://ddec1-0-en-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fdocs.oasis%2dopen.org%2fvirtio%2fvirtio%2fv1.1%2fvirtio%2dv1.1.pdf&umid=d1786ace-e8ea-40e8-9665-96c0949174e5&auth=53c7c7de28b92dfd96e93d9dd61a23e634d2fbec-39b15885ceebe9fda9357320aec1ccbac416a470
> >
> > Signed-off-by: Igor Skalkin <[email protected]>
> >
> > This is all true enough, but the problem is
> > 1. changing uapi like this can't be done, will break userspace
> > 2. the driver has more issues and no one seems to want to
> > maintain it.
> > I posted a patch "Bluetooth: virtio_bt: mark broken" and intend
> > to merge it for this release.
> >
> > This is very sad. We already use this driver in our projects.
>
> Ping. If we still have no maintainer I'm marking it broken, users
> should at least be warned.

Please resend.

>
> > Our virtio bluetooth device has two backends - HCI_USER socket backend for one
> > platform and uart backend for the other, and works well (after applying your
> > "[PATCH] Bluetooth: virtio_bt: fix device remove") patch, so this "device
> > removal" problem can probably be considered solved .
> > We could help with the rest of the problems you listed that can be solved
> > (specification, QEMU support).
> > And the only problem that is difficult to solve (because of the need to change
> > UAPI header files) is just this one with unaligned configuration fields.
> > At the moment, it does not reproduce, because without VIRTIO_BT_F_VND_HCI
> > (Indicates vendor command support) feature negotiated, the driver does not
> > read the non-aligned configuration fields.
> >
> > So, what would you advise us to do? Continuing to use the "marked broken"
> > driver, start writing a specification for a new from scratch, better one?
> > Or is there any way to bring this one back to life?
> >
> >
> >
> > ---
> > include/uapi/linux/virtio_bt.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/virtio_bt.h b/include/uapi/linux/virtio_bt.h
> > index a7bd48daa9a9..adc03709cc4f 100644
> > --- a/include/uapi/linux/virtio_bt.h
> > +++ b/include/uapi/linux/virtio_bt.h
> > @@ -23,9 +23,9 @@ enum virtio_bt_config_vendor {
> > };
> >
> > struct virtio_bt_config {
> > - __u8 type;
> > __u16 vendor;
> > __u16 msft_opcode;
> > + __u8 type;
> > } __attribute__((packed));
> >
> > #endif /* _UAPI_LINUX_VIRTIO_BT_H */
> > --
> > 2.34.1
> >
> > --
> >
> > Best regards,
> >
> > Igor Skalkin
> > Software Engineer
> >
> > OpenSynergy GmbH
> > Rotherstr. 20, 10245 Berlin
> >
> > [email protected]
> > http://www.opensynergy.com
> >
> > registered: Amtsgericht Charlottenburg, HRB 108616B
> > General Management: Rolf Morich, Stefaan Sonck Thiebaut
> >
> >
> > Please mind our privacy notice pursuant to Art. 13 GDPR. // Unsere Hinweise zum
> > Datenschutz gem. Art. 13 DSGVO finden Sie hier.
>


--
Luiz Augusto von Dentz

2022-10-11 12:25:44

by Igor Skalkin

[permalink] [raw]
Subject: Re: [PATCH] virtio_bt: Fix alignment in configuration struct

Hi Luiz,

Current version of this patch is wrong [q]changing uapi like this can't
be done, will break userspace[/q], next version is in process, will be
sent in few days.
Best regards,
Igor
On 10/7/22 21:33, Luiz Augusto von Dentz wrote:
> Hi Michael,
>
> On Fri, Oct 7, 2022 at 6:03 AM Michael S. Tsirkin <[email protected]> wrote:
>>
>> On Mon, Aug 08, 2022 at 02:04:43PM +0200, Igor Skalkin wrote:
>>> On 8/8/22 01:00, Michael S. Tsirkin wrote:
>>>
>>> On Mon, Aug 08, 2022 at 12:11:52AM +0200, Igor Skalkin wrote:
>>>
>>> According to specification [1], "For the device-specific configuration
>>> space, the driver MUST use 8 bit wide accesses for 8 bit wide fields,
>>> 16 bit wide and aligned accesses for 16 bit wide fields and 32 bit wide
>>> and aligned accesses for 32 and 64 bit wide fields.".
>>>
>>> Current version of the configuration structure:
>>>
>>> struct virtio_bt_config {
>>> __u8 type;
>>> __u16 vendor;
>>> __u16 msft_opcode;
>>> } __attribute__((packed));
>>>
>>> has both 16bit fields non-aligned.
>>>
>>> This commit fixes it.
>>>
>>> [1] https://ddec1-0-en-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fdocs.oasis%2dopen.org%2fvirtio%2fvirtio%2fv1.1%2fvirtio%2dv1.1.pdf&umid=b1110db2-819d-4f27-b35e-18ac23ce0ab4&auth=53c7c7de28b92dfd96e93d9dd61a23e634d2fbec-2c53002097633a932e7d67b899e6bf6999cdc899
>>>
>>> Signed-off-by: Igor Skalkin <[email protected]>
>>>
>>> This is all true enough, but the problem is
>>> 1. changing uapi like this can't be done, will break userspace
>>> 2. the driver has more issues and no one seems to want to
>>> maintain it.
>>> I posted a patch "Bluetooth: virtio_bt: mark broken" and intend
>>> to merge it for this release.
>>>
>>> This is very sad. We already use this driver in our projects.
>>
>> Ping. If we still have no maintainer I'm marking it broken, users
>> should at least be warned.
>
> Please resend.
>
>>
>>> Our virtio bluetooth device has two backends - HCI_USER socket backend for one
>>> platform and uart backend for the other, and works well (after applying your
>>> "[PATCH] Bluetooth: virtio_bt: fix device remove") patch, so this "device
>>> removal" problem can probably be considered solved .
>>> We could help with the rest of the problems you listed that can be solved
>>> (specification, QEMU support).
>>> And the only problem that is difficult to solve (because of the need to change
>>> UAPI header files) is just this one with unaligned configuration fields.
>>> At the moment, it does not reproduce, because without VIRTIO_BT_F_VND_HCI
>>> (Indicates vendor command support) feature negotiated, the driver does not
>>> read the non-aligned configuration fields.
>>>
>>> So, what would you advise us to do? Continuing to use the "marked broken"
>>> driver, start writing a specification for a new from scratch, better one?
>>> Or is there any way to bring this one back to life?
>>>
>>>
>>>
>>> ---
>>> include/uapi/linux/virtio_bt.h | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/include/uapi/linux/virtio_bt.h b/include/uapi/linux/virtio_bt.h
>>> index a7bd48daa9a9..adc03709cc4f 100644
>>> --- a/include/uapi/linux/virtio_bt.h
>>> +++ b/include/uapi/linux/virtio_bt.h
>>> @@ -23,9 +23,9 @@ enum virtio_bt_config_vendor {
>>> };
>>>
>>> struct virtio_bt_config {
>>> - __u8 type;
>>> __u16 vendor;
>>> __u16 msft_opcode;
>>> + __u8 type;
>>> } __attribute__((packed));
>>>
>>> #endif /* _UAPI_LINUX_VIRTIO_BT_H */
>>> --
>>> 2.34.1
>>>
>>> --
>>>
>>> Best regards,
>>>
>>> Igor Skalkin
>>> Software Engineer
>>>
>>> OpenSynergy GmbH
>>> Rotherstr. 20, 10245 Berlin
>>>
>>> [email protected]
>>> http://www.opensynergy.com
>>>
>>> registered: Amtsgericht Charlottenburg, HRB 108616B
>>> General Management: Rolf Morich, Stefaan Sonck Thiebaut
>>>
>>>
>>> Please mind our privacy notice pursuant to Art. 13 GDPR. // Unsere Hinweise zum
>>> Datenschutz gem. Art. 13 DSGVO finden Sie hier.
>>
>
>

Please mind our privacy notice<https://www.opensynergy.com/datenschutzerklaerung/privacy-notice-for-business-partners-pursuant-to-article-13-of-the-general-data-protection-regulation-gdpr/> pursuant to Art. 13 GDPR. // Unsere Hinweise zum Datenschutz gem. Art. 13 DSGVO finden Sie hier.<https://www.opensynergy.com/de/datenschutzerklaerung/datenschutzhinweise-fuer-geschaeftspartner-gem-art-13-dsgvo/>

2022-10-11 19:51:23

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: Re: [PATCH] virtio_bt: Fix alignment in configuration struct

Hi Igor,

On Tue, Oct 11, 2022 at 5:23 AM Igor Skalkin
<[email protected]> wrote:
>
> Hi Luiz,
>
> Current version of this patch is wrong [q]changing uapi like this can't
> be done, will break userspace[/q], next version is in process, will be
> sent in few days.

Thanks for the update, I will wait for the next version then.

> Best regards,
> Igor
> On 10/7/22 21:33, Luiz Augusto von Dentz wrote:
> > Hi Michael,
> >
> > On Fri, Oct 7, 2022 at 6:03 AM Michael S. Tsirkin <[email protected]> wrote:
> >>
> >> On Mon, Aug 08, 2022 at 02:04:43PM +0200, Igor Skalkin wrote:
> >>> On 8/8/22 01:00, Michael S. Tsirkin wrote:
> >>>
> >>> On Mon, Aug 08, 2022 at 12:11:52AM +0200, Igor Skalkin wrote:
> >>>
> >>> According to specification [1], "For the device-specific configuration
> >>> space, the driver MUST use 8 bit wide accesses for 8 bit wide fields,
> >>> 16 bit wide and aligned accesses for 16 bit wide fields and 32 bit wide
> >>> and aligned accesses for 32 and 64 bit wide fields.".
> >>>
> >>> Current version of the configuration structure:
> >>>
> >>> struct virtio_bt_config {
> >>> __u8 type;
> >>> __u16 vendor;
> >>> __u16 msft_opcode;
> >>> } __attribute__((packed));
> >>>
> >>> has both 16bit fields non-aligned.
> >>>
> >>> This commit fixes it.
> >>>
> >>> [1] https://ddec1-0-en-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fdocs.oasis%2dopen.org%2fvirtio%2fvirtio%2fv1.1%2fvirtio%2dv1.1.pdf&umid=b1110db2-819d-4f27-b35e-18ac23ce0ab4&auth=53c7c7de28b92dfd96e93d9dd61a23e634d2fbec-2c53002097633a932e7d67b899e6bf6999cdc899
> >>>
> >>> Signed-off-by: Igor Skalkin <[email protected]>
> >>>
> >>> This is all true enough, but the problem is
> >>> 1. changing uapi like this can't be done, will break userspace
> >>> 2. the driver has more issues and no one seems to want to
> >>> maintain it.
> >>> I posted a patch "Bluetooth: virtio_bt: mark broken" and intend
> >>> to merge it for this release.
> >>>
> >>> This is very sad. We already use this driver in our projects.
> >>
> >> Ping. If we still have no maintainer I'm marking it broken, users
> >> should at least be warned.
> >
> > Please resend.
> >
> >>
> >>> Our virtio bluetooth device has two backends - HCI_USER socket backend for one
> >>> platform and uart backend for the other, and works well (after applying your
> >>> "[PATCH] Bluetooth: virtio_bt: fix device remove") patch, so this "device
> >>> removal" problem can probably be considered solved .
> >>> We could help with the rest of the problems you listed that can be solved
> >>> (specification, QEMU support).
> >>> And the only problem that is difficult to solve (because of the need to change
> >>> UAPI header files) is just this one with unaligned configuration fields.
> >>> At the moment, it does not reproduce, because without VIRTIO_BT_F_VND_HCI
> >>> (Indicates vendor command support) feature negotiated, the driver does not
> >>> read the non-aligned configuration fields.
> >>>
> >>> So, what would you advise us to do? Continuing to use the "marked broken"
> >>> driver, start writing a specification for a new from scratch, better one?
> >>> Or is there any way to bring this one back to life?
> >>>
> >>>
> >>>
> >>> ---
> >>> include/uapi/linux/virtio_bt.h | 2 +-
> >>> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/include/uapi/linux/virtio_bt.h b/include/uapi/linux/virtio_bt.h
> >>> index a7bd48daa9a9..adc03709cc4f 100644
> >>> --- a/include/uapi/linux/virtio_bt.h
> >>> +++ b/include/uapi/linux/virtio_bt.h
> >>> @@ -23,9 +23,9 @@ enum virtio_bt_config_vendor {
> >>> };
> >>>
> >>> struct virtio_bt_config {
> >>> - __u8 type;
> >>> __u16 vendor;
> >>> __u16 msft_opcode;
> >>> + __u8 type;
> >>> } __attribute__((packed));
> >>>
> >>> #endif /* _UAPI_LINUX_VIRTIO_BT_H */
> >>> --
> >>> 2.34.1
> >>>
> >>> --
> >>>
> >>> Best regards,
> >>>
> >>> Igor Skalkin
> >>> Software Engineer
> >>>
> >>> OpenSynergy GmbH
> >>> Rotherstr. 20, 10245 Berlin
> >>>
> >>> [email protected]
> >>> http://www.opensynergy.com
> >>>
> >>> registered: Amtsgericht Charlottenburg, HRB 108616B
> >>> General Management: Rolf Morich, Stefaan Sonck Thiebaut
> >>>
> >>>
> >>> Please mind our privacy notice pursuant to Art. 13 GDPR. // Unsere Hinweise zum
> >>> Datenschutz gem. Art. 13 DSGVO finden Sie hier.
> >>
> >
> >
>
> Please mind our privacy notice<https://www.opensynergy.com/datenschutzerklaerung/privacy-notice-for-business-partners-pursuant-to-article-13-of-the-general-data-protection-regulation-gdpr/> pursuant to Art. 13 GDPR. // Unsere Hinweise zum Datenschutz gem. Art. 13 DSGVO finden Sie hier.<https://www.opensynergy.com/de/datenschutzerklaerung/datenschutzhinweise-fuer-geschaeftspartner-gem-art-13-dsgvo/>



--
Luiz Augusto von Dentz