RE: [EXT] Re: [PATCH] cxl/mbox: Add Get Log Capabilities, Clear Log and Get Supported Logs Sub-List commands

[Srinivasulu Opensrc <sthanneeru.opensrc@micron.com>]

> -----Original Message-----
> From: Srinivasulu Opensrc <sthanneeru.opensrc@micron.com>
> Sent: Wednesday, February 14, 2024 9:39 PM
> To: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
> Cc: linux-cxl@vger.kernel.org; linux-mm@kvack.org;
> 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>; shiju.jose@huawei.com
> Subject: RE: [EXT] Re: [PATCH] cxl/mbox: Add Get Log Capabilities, Clear Log
> and Get Supported Logs Sub-List commands
> 
> 
> 
> > -----Original Message-----
> > From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
> > Sent: Thursday, February 8, 2024 6:27 PM
> > To: Srinivasulu Opensrc <sthanneeru.opensrc@micron.com>
> > Cc: linux-cxl@vger.kernel.org; linux-mm@kvack.org;
> > 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>; shiju.jose@huawei.com
> > Subject: [EXT] Re: [PATCH] cxl/mbox: Add Get Log Capabilities, Clear Log and
> > Get Supported Logs Sub-List commands
> >
> > CAUTION: EXTERNAL EMAIL. Do not click links or open attachments unless
> > you recognize the sender and were expecting this message.
> >
> >
> > On Wed, 7 Feb 2024 16:06:34 +0530
> > <sthanneeru.opensrc@micron.com> wrote:
> >
> > > From: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
> > >
> > > Adding UAPI support for
> > > 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.
> > >
> > > Signed-off-by: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
> >
> > Hi Srinivasulu,
> >
> > Whilst I can conjecture some valid reasons to expose these to
> > userspace, can you add some examples to this patch description?
> >
> > We might want to filter the clear in particular to avoid a clash
> > with the driver log handling. That is only allow it for vendor
> > logs.
> 
> Are you suggesting that I should restrict the "Vendor Debug Log" functionality
> to
> only apply to Vendor logs.? Why not include Component State Dumps logs
> that
> support the clear log feature?

Sorry for the typo.

Are you suggesting that I should restrict the "Clear log command" functionality from user space
to only apply to "Vendor Debug Log".? 
Why not include Component State Dumps logs that support the clear log feature?

> 
> I might be overlooking something; please enlighten me.
> 
> For example, following both supports Clear log in our setups.
> * 5e1819d9-11a9-400c-811f-d60719403d86 - Vendor Debug Log
> * b3fab4cf-01b6-4332-943e-5e9962f23567 - Component State Dump Log
> 
> >
> > Perhaps split the patch into 2 parts. The less controversial
> > GET_LOG_CAPS and GET_LOG_SUBLIST, followed by a patch for the
> > destructive clear log.
> >
> > The memory scrub handling might well
> > access the ECS log for example (I don't think the current proposal
> > yet does this).
> >
> > Jonathan
> >
> >
> > > ---
> > >  drivers/cxl/core/mbox.c      | 3 +++
> > >  drivers/cxl/cxlmem.h         | 3 +++
> > >  include/uapi/linux/cxl_mem.h | 3 +++
> > >  3 files changed, 9 insertions(+)
> > >
> > > diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> > > index 27166a411705..64a44e286488 100644
> > > --- a/drivers/cxl/core/mbox.c
> > > +++ b/drivers/cxl/core/mbox.c
> > > @@ -64,6 +64,9 @@ static struct cxl_mem_command
> > cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
> > >       CXL_CMD(SET_SHUTDOWN_STATE, 0x1, 0, 0),
> > >       CXL_CMD(GET_SCAN_MEDIA_CAPS, 0x10, 0x4, 0),
> > >       CXL_CMD(GET_TIMESTAMP, 0, 0x8, 0),
> > > +     CXL_CMD(GET_LOG_CAPS, 0x10, 0x4, 0),
> > > +     CXL_CMD(CLEAR_LOG, 0x10, 0, 0),
> > > +     CXL_CMD(GET_LOG_SUBLIST, 0x2, CXL_VARIABLE_PAYLOAD, 0),
> > >  };
> > >
> > >  /*
> > > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> > > index 5303d6942b88..4128c810051c 100644
> > > --- a/drivers/cxl/cxlmem.h
> > > +++ b/drivers/cxl/cxlmem.h
> > > @@ -529,6 +529,9 @@ enum cxl_opcode {
> > >       CXL_MBOX_OP_SET_TIMESTAMP       = 0x0301,
> > >       CXL_MBOX_OP_GET_SUPPORTED_LOGS  = 0x0400,
> > >       CXL_MBOX_OP_GET_LOG             = 0x0401,
> > > +     CXL_MBOX_OP_GET_LOG_CAPS        = 0x0402,
> > > +     CXL_MBOX_OP_CLEAR_LOG           = 0x0403,
> > > +     CXL_MBOX_OP_GET_LOG_SUBLIST     = 0x0405,
> >
> > Name should include something to make it clear this is getting
> > sublist of 'supported' logs.  Not the log.
> >
> > >       CXL_MBOX_OP_IDENTIFY            = 0x4000,
> > >       CXL_MBOX_OP_GET_PARTITION_INFO  = 0x4100,
> > >       CXL_MBOX_OP_SET_PARTITION_INFO  = 0x4101,
> > > diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
> > > index 42066f4eb890..d2df9782a5ef 100644
> > > --- a/include/uapi/linux/cxl_mem.h
> > > +++ b/include/uapi/linux/cxl_mem.h
> > > @@ -47,6 +47,9 @@
> > >       ___DEPRECATED(SCAN_MEDIA, "Scan Media"),                          \
> > >       ___DEPRECATED(GET_SCAN_MEDIA, "Get Scan Media Results"),          \
> > >       ___C(GET_TIMESTAMP, "Get Timestamp"),                             \
> > > +     ___C(GET_LOG_CAPS, "Get Log Capabilities"),                       \
> > > +     ___C(CLEAR_LOG, "Clear Log"),                                     \
> > > +     ___C(GET_LOG_SUBLIST, "Get Log Sublist"),                         \
> >
> > Likewise, mention it's list of supported logs.
> >
> > >       ___C(MAX, "invalid / last command")
> > >
> > >  #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
>