diff mbox

[v4,2/3] pci: add QEMU-specific PCI capability structure

Message ID 1501964994-5257-3-git-send-email-zuban32s@gmail.com
State New
Headers show

Commit Message

Aleksandr Bezzubikov Aug. 5, 2017, 8:29 p.m. UTC
On PCI init PCI bridge devices may need some
extra info about bus number to reserve, IO, memory and
prefetchable memory limits. QEMU can provide this
with special vendor-specific PCI capability.

This capability is intended to be used only
for Red Hat PCI bridges, i.e. QEMU cooperation.

Signed-off-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
---
 src/fw/dev-pci.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 src/fw/dev-pci.h

Comments

Marcel Apfelbaum Aug. 7, 2017, 3:52 p.m. UTC | #1
On 05/08/2017 23:29, Aleksandr Bezzubikov wrote:
> On PCI init PCI bridge devices may need some
> extra info about bus number to reserve, IO, memory and
> prefetchable memory limits. QEMU can provide this
> with special vendor-specific PCI capability.
> 
> This capability is intended to be used only
> for Red Hat PCI bridges, i.e. QEMU cooperation.
> 
> Signed-off-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
> ---
>   src/fw/dev-pci.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 50 insertions(+)
>   create mode 100644 src/fw/dev-pci.h
> 
> diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
> new file mode 100644
> index 0000000..2c8ddb0

Hi Aleksandr,

> --- /dev/null
> +++ b/src/fw/dev-pci.h
> @@ -0,0 +1,50 @@
> +#ifndef _PCI_CAP_H
> +#define _PCI_CAP_H
> +
> +#include "types.h"
> +
> +/*
> +

Please use the standard comment:

/*
  *
  *
  */


> +QEMU-specific vendor(Red Hat)-specific capability.
> +It's intended to provide some hints for firmware to init PCI devices.
> +
> +Its structure is shown below:
> +
> +Header:
> +
> +u8 id;       Standard PCI Capability Header field
> +u8 next;     Standard PCI Capability Header field
> +u8 len;      Standard PCI Capability Header field
> +u8 type;     Red Hat vendor-specific capability type:
> +               now only REDHAT_CAP_TYP_QEMU=1 exists

Typo o the line before, but I think you don't need it there.

> +Data:
> +
> +u32 bus_res;            minimum bus number to reserve;
> +                        this is necessary for PCI Express Root Ports
> +                        to support PCIE-to-PCI bridge hotplug

I would add a broader class of usage:
      necessary for nesting PCI bridges hotplug.

> +u64 io;                 IO space to reserve
> +u64 mem;                non-prefetchable memory space to reserve
> +u64 prefetchable_mem;   prefetchable memory space to reserve
> +

Layout looks good to me.

> +If any field value in Data section is -1,
> +it means that such kind of reservation
> +is not needed and must be ignored.
> +

-1 is not a valid value for unsigned fields, you may
want to say 0xff..f or some other way.

> +*/
> +
> +/* Offset of vendor-specific capability type field */
> +#define PCI_CAP_REDHAT_TYPE  3

May I ask why why '3'? I am not against it, I just
want to understand the number.

> +
> +/* List of valid Red Hat vendor-specific capability types */
> +#define REDHAT_CAP_TYPE_QEMU    1

I think I pointed this in another thread, the name is
too vague, please change it to something like:
    REDHAT_CAP_RES_RESERVE_QEMU
that narrows down the intend.

> +
> +
> +/* Offsets of QEMU capability fields */
> +#define QEMU_PCI_CAP_BUS_RES        4
> +#define QEMU_PCI_CAP_LIMITS_OFFSET  8
> +#define QEMU_PCI_CAP_IO             8
> +#define QEMU_PCI_CAP_MEM            16
> +#define QEMU_PCI_CAP_PREF_MEM       24
> +#define QEMU_PCI_CAP_SIZE           32
> +
> +#endif /* _PCI_CAP_H */
> 

The layout looks good to me.

Thanks,
Marcel
Aleksandr Bezzubikov Aug. 7, 2017, 4:02 p.m. UTC | #2
2017-08-07 18:52 GMT+03:00 Marcel Apfelbaum <marcel@redhat.com>:
> On 05/08/2017 23:29, Aleksandr Bezzubikov wrote:
>>
>> On PCI init PCI bridge devices may need some
>> extra info about bus number to reserve, IO, memory and
>> prefetchable memory limits. QEMU can provide this
>> with special vendor-specific PCI capability.
>>
>> This capability is intended to be used only
>> for Red Hat PCI bridges, i.e. QEMU cooperation.
>>
>> Signed-off-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
>> ---
>>   src/fw/dev-pci.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 50 insertions(+)
>>   create mode 100644 src/fw/dev-pci.h
>>
>> diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
>> new file mode 100644
>> index 0000000..2c8ddb0
>
>
> Hi Aleksandr,
>

Hi Marcel,

>> --- /dev/null
>> +++ b/src/fw/dev-pci.h
>> @@ -0,0 +1,50 @@
>> +#ifndef _PCI_CAP_H
>> +#define _PCI_CAP_H
>> +
>> +#include "types.h"
>> +
>> +/*
>> +
>
>
> Please use the standard comment:
>
> /*
>  *
>  *
>  */
>
>
>> +QEMU-specific vendor(Red Hat)-specific capability.
>> +It's intended to provide some hints for firmware to init PCI devices.
>> +
>> +Its structure is shown below:
>> +
>> +Header:
>> +
>> +u8 id;       Standard PCI Capability Header field
>> +u8 next;     Standard PCI Capability Header field
>> +u8 len;      Standard PCI Capability Header field
>> +u8 type;     Red Hat vendor-specific capability type:
>> +               now only REDHAT_CAP_TYP_QEMU=1 exists
>
>
> Typo o the line before, but I think you don't need it there.
>
>> +Data:
>> +
>> +u32 bus_res;            minimum bus number to reserve;
>> +                        this is necessary for PCI Express Root Ports
>> +                        to support PCIE-to-PCI bridge hotplug
>
>
> I would add a broader class of usage:
>      necessary for nesting PCI bridges hotplug.
>
>> +u64 io;                 IO space to reserve
>> +u64 mem;                non-prefetchable memory space to reserve
>> +u64 prefetchable_mem;   prefetchable memory space to reserve
>> +
>
>
> Layout looks good to me.
>
>> +If any field value in Data section is -1,
>> +it means that such kind of reservation
>> +is not needed and must be ignored.
>> +
>
>
> -1 is not a valid value for unsigned fields, you may
> want to say 0xff..f or some other way.

I meant cast to unsigned here (because we still use unsigned types),
but if it can mislead someone I will change this.

>
>> +*/
>> +
>> +/* Offset of vendor-specific capability type field */
>> +#define PCI_CAP_REDHAT_TYPE  3
>
>
> May I ask why why '3'? I am not against it, I just
> want to understand the number.
>

This is actually an offset to this field

>> +
>> +/* List of valid Red Hat vendor-specific capability types */
>> +#define REDHAT_CAP_TYPE_QEMU    1
>
>
> I think I pointed this in another thread, the name is
> too vague, please change it to something like:
>    REDHAT_CAP_RES_RESERVE_QEMU
> that narrows down the intend.
>

What does the first 'RES' mean?

>> +
>> +
>> +/* Offsets of QEMU capability fields */
>> +#define QEMU_PCI_CAP_BUS_RES        4
>> +#define QEMU_PCI_CAP_LIMITS_OFFSET  8
>> +#define QEMU_PCI_CAP_IO             8
>> +#define QEMU_PCI_CAP_MEM            16
>> +#define QEMU_PCI_CAP_PREF_MEM       24
>> +#define QEMU_PCI_CAP_SIZE           32
>> +
>> +#endif /* _PCI_CAP_H */
>>
>
> The layout looks good to me.
>
> Thanks,
> Marcel
Marcel Apfelbaum Aug. 7, 2017, 4:33 p.m. UTC | #3
On 07/08/2017 19:02, Alexander Bezzubikov wrote:
> 2017-08-07 18:52 GMT+03:00 Marcel Apfelbaum <marcel@redhat.com>:
>> On 05/08/2017 23:29, Aleksandr Bezzubikov wrote:
>>>
>>> On PCI init PCI bridge devices may need some
>>> extra info about bus number to reserve, IO, memory and
>>> prefetchable memory limits. QEMU can provide this
>>> with special vendor-specific PCI capability.
>>>
>>> This capability is intended to be used only
>>> for Red Hat PCI bridges, i.e. QEMU cooperation.
>>>
>>> Signed-off-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
>>> ---
>>>    src/fw/dev-pci.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>>    1 file changed, 50 insertions(+)
>>>    create mode 100644 src/fw/dev-pci.h
>>>
>>> diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
>>> new file mode 100644
>>> index 0000000..2c8ddb0
>>
>>
>> Hi Aleksandr,
>>
> 
> Hi Marcel,
> 
>>> --- /dev/null
>>> +++ b/src/fw/dev-pci.h
>>> @@ -0,0 +1,50 @@
>>> +#ifndef _PCI_CAP_H
>>> +#define _PCI_CAP_H
>>> +
>>> +#include "types.h"
>>> +
>>> +/*
>>> +
>>
>>
>> Please use the standard comment:
>>
>> /*
>>   *
>>   *
>>   */
>>
>>
>>> +QEMU-specific vendor(Red Hat)-specific capability.
>>> +It's intended to provide some hints for firmware to init PCI devices.
>>> +
>>> +Its structure is shown below:
>>> +
>>> +Header:
>>> +
>>> +u8 id;       Standard PCI Capability Header field
>>> +u8 next;     Standard PCI Capability Header field
>>> +u8 len;      Standard PCI Capability Header field
>>> +u8 type;     Red Hat vendor-specific capability type:
>>> +               now only REDHAT_CAP_TYP_QEMU=1 exists
>>
>>
>> Typo o the line before, but I think you don't need it there.
>>
>>> +Data:
>>> +
>>> +u32 bus_res;            minimum bus number to reserve;
>>> +                        this is necessary for PCI Express Root Ports
>>> +                        to support PCIE-to-PCI bridge hotplug
>>
>>
>> I would add a broader class of usage:
>>       necessary for nesting PCI bridges hotplug.
>>
>>> +u64 io;                 IO space to reserve
>>> +u64 mem;                non-prefetchable memory space to reserve
>>> +u64 prefetchable_mem;   prefetchable memory space to reserve
>>> +
>>
>>
>> Layout looks good to me.
>>
>>> +If any field value in Data section is -1,
>>> +it means that such kind of reservation
>>> +is not needed and must be ignored.
>>> +
>>
>>
>> -1 is not a valid value for unsigned fields, you may
>> want to say 0xff..f or some other way.
> 
> I meant cast to unsigned here (because we still use unsigned types),
> but if it can mislead someone I will change this.
> 
We should not document signed values for unsigned fields,
even if the reason is "best practices."

>>
>>> +*/
>>> +
>>> +/* Offset of vendor-specific capability type field */
>>> +#define PCI_CAP_REDHAT_TYPE  3
>>
>>
>> May I ask why why '3'? I am not against it, I just
>> want to understand the number.
>>
> 
> This is actually an offset to this field
> 

OK, so it should end with 'offset' to be clear.
I was mislead.

>>> +
>>> +/* List of valid Red Hat vendor-specific capability types */
>>> +#define REDHAT_CAP_TYPE_QEMU    1
>>
>>
>> I think I pointed this in another thread, the name is
>> too vague, please change it to something like:
>>     REDHAT_CAP_RES_RESERVE_QEMU
>> that narrows down the intend.
>>
> 
> What does the first 'RES' mean?

Resource.

I don't mind you change it how you seem fit,
just make it clear what it does. Is about
resource reserving, not a general capability.


Thanks,
Marcel

> 
>>> +
>>> +
>>> +/* Offsets of QEMU capability fields */
>>> +#define QEMU_PCI_CAP_BUS_RES        4
>>> +#define QEMU_PCI_CAP_LIMITS_OFFSET  8
>>> +#define QEMU_PCI_CAP_IO             8
>>> +#define QEMU_PCI_CAP_MEM            16
>>> +#define QEMU_PCI_CAP_PREF_MEM       24
>>> +#define QEMU_PCI_CAP_SIZE           32
>>> +
>>> +#endif /* _PCI_CAP_H */
>>>
>>
>> The layout looks good to me.
>>
>> Thanks,
>> Marcel
> 
> 
>
diff mbox

Patch

diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
new file mode 100644
index 0000000..2c8ddb0
--- /dev/null
+++ b/src/fw/dev-pci.h
@@ -0,0 +1,50 @@ 
+#ifndef _PCI_CAP_H
+#define _PCI_CAP_H
+
+#include "types.h"
+
+/*
+
+QEMU-specific vendor(Red Hat)-specific capability.
+It's intended to provide some hints for firmware to init PCI devices.
+
+Its structure is shown below:
+
+Header:
+
+u8 id;       Standard PCI Capability Header field
+u8 next;     Standard PCI Capability Header field
+u8 len;      Standard PCI Capability Header field
+u8 type;     Red Hat vendor-specific capability type:
+               now only REDHAT_CAP_TYP_QEMU=1 exists
+Data:
+
+u32 bus_res;            minimum bus number to reserve;
+                        this is necessary for PCI Express Root Ports
+                        to support PCIE-to-PCI bridge hotplug
+u64 io;                 IO space to reserve
+u64 mem;                non-prefetchable memory space to reserve
+u64 prefetchable_mem;   prefetchable memory space to reserve
+
+If any field value in Data section is -1,
+it means that such kind of reservation
+is not needed and must be ignored.
+
+*/
+
+/* Offset of vendor-specific capability type field */
+#define PCI_CAP_REDHAT_TYPE  3
+
+/* List of valid Red Hat vendor-specific capability types */
+#define REDHAT_CAP_TYPE_QEMU    1
+
+
+/* Offsets of QEMU capability fields */
+#define QEMU_PCI_CAP_BUS_RES        4
+#define QEMU_PCI_CAP_LIMITS_OFFSET  8
+#define QEMU_PCI_CAP_IO             8
+#define QEMU_PCI_CAP_MEM            16
+#define QEMU_PCI_CAP_PREF_MEM       24
+#define QEMU_PCI_CAP_SIZE           32
+
+#endif /* _PCI_CAP_H */