Re: [EXT] RE: [PATCH v3 0/2] Add log related mailbox commands

[ajay.opensrc <ajay.opensrc@micron.com>]

 
> Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote:
> > Srinivasulu Opensrc <sthanneeru.opensrc@micron.com> wrote:
> >
> 
> > > >-----Original Message-----
> > > >From: Dan Williams <dan.j.williams@intel.com>
> > > >Sent: Wednesday, March 27, 2024 5:07 AM
> > > >To: Srinivasulu Opensrc <sthanneeru.opensrc@micron.com>; linux-
> > > >cxl@vger.kernel.org
> > > >Cc: Jonathan.Cameron@huawei.com; dan.j.williams@intel.com;
> > > >john@jagalactic.com; Eishan Mirakhur <emirakhur@micron.com>; Ajay
> > > >Joshi <ajayjoshi@micron.com>; Ravis OpenSrc
> > > ><Ravis.OpenSrc@micron.com>; Srinivasulu Thanneeru
> > > ><sthanneeru@micron.com>
> > > >Subject: [EXT] RE: [PATCH v3 0/2] Add log related mailbox commands
> > > >
> > > >CAUTION: EXTERNAL EMAIL. Do not click links or open attachments
> > > >unless you recognize the sender and were expecting this message.
> > > >
> > > >
> > > >sthanneeru.opensrc@ wrote:
> > > >> From: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
> > > >>
> > > >> Add support to expose following mailbox commands to userspace for
> > > >> clearing and populating the Vendor debug log in certain
> > > >> scenarios, allowing for the aggregation of results over time.
> > > >>
> > > >> 1. CXL r3.1 8.2.9.5.3 Get Log Capabilities.
> > > >> 2. CXL r3.1 8.2.9.5.4 Clear Log commands.
> > > >> 3. CXL r3.1 8.2.9.5.6 Get Supported Logs Sub-List.
> > > >>
> > > >> ---
> > > >> Changes in v3:
> > > >> - 'Component State Dump log' has several caveats for ioctl()
> > > >>    not being a suitable ABI as pointed in v2.(Dan Williams)
> > > >> - Remove Component State Dump from Clear log filter.
> > > >> - Implement a seperate patch(yet to do) to address issues as
> > > >> pointed in
> > v2.
> > > >
> > > >Circling back to this question... I had overlooked the fact that in
> > > >v3.1 the "Request Abort Background Operation" command was added
> > (8.2.9.1.5).
> > > >With that the kernel can safely support background commands with
> > > >indefinite residency. So as long as the device supports that
> > > >command and advertises that Log populate requests can be cancelled
> > > >then we can build a facility to cancel any user-submitted
> > > >background commands when a kernel internal need for the background
> command slot arises.
> > >
> > > I don't have the access to test "Request Abort Background Operation."
> > > Previously, we posted RFC for default time for background operations.
> > >
> > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> >
> %2F&data=05%7C02%7Cajayjoshi%40micron.com%7Cf8029f5d498b4f0e64fb
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> >
> 387ed0%7Cf38a5ecd28134862b11bac1d563c806f%7C0%7C0%7C6384822468
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> %7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL
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> k1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=Lv366Ff7nRD9zI6F0AQC
> e%2F9f%2F
> > QwNiL%2FCpND2cpfX6E0%3D&reserved=0
> > > .kernel.org%2Flinux-mm%2F20240207105349.301-1-
> > sthanneeru.opensrc%40mic
> > >
> > ron.com%2F&data=05%7C02%7Cajayjoshi%40micron.com%7Cabe61f69d40
> > 2460e2f2
> > >
> > b08dc55964860%7Cf38a5ecd28134862b11bac1d563c806f%7C0%7C0%7C
> > 63847935119
> > >
> > 7749869%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoi
> > V2luMzIiLC
> > >
> > JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=QyxjJi2iLMTSTl
> > R46rv9k5
> > > U%2FDZVrKruaaunew8HMR9E%3D&reserved=0
> > >
> > >  Could you please guide me on how to proceed with this current patch
> > series?
> >
> > Whilst QEMU emulation doesn't yet support background command
> aborting,
> > it wouldn't be that hard to add and would provide a route to test this
> > functionality.
> > We've done similar in a few other cases where no one had any hardware
> yet.
> >
> > Of course that might not help you if you have silicon that doesn't
> > implement it but I agree with Dan that it is a lot less problematic to
> > allow for unbounded background ops if we can stop them for other urgent
> activity.
> >
> 
> Thanks Jonathan and Dan. Agree with you on the background command
> handling.
> The series which Srini (sthanneeru.opensrc) has submitted has 2 patches:
> cxl/mbox: Add Get Log Capabilities and Get Supported Logs Sub-List
>     commands
> cxl/mbox: Add Clear Log mailbox command
> The commands in these patches(opcodes: 0402h, 0403h, 0405h) don't seem
> to have any background handling as of 3.1.
> Do you think these patches seem ok or do you feel something is missing
> here?
>
 
Any input or review comment here would be highly appreciated.
  
> 
> Ajay
> 
> > Jonathan