netdev - Re: [PATCH v14 02/22] sfc: add cxl support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aBzmCjCStxiQRJkK@aschofie-mobl2.lan>
Date: Thu, 8 May 2025 10:12:42 -0700
From: Alison Schofield <alison.schofield@...el.com>
To: Alejandro Lucero Palau <alucerop@....com>
CC: <alejandro.lucero-palau@....com>, <linux-cxl@...r.kernel.org>,
	<netdev@...r.kernel.org>, <dan.j.williams@...el.com>, <edward.cree@....com>,
	<davem@...emloft.net>, <kuba@...nel.org>, <pabeni@...hat.com>,
	<edumazet@...gle.com>, <dave.jiang@...el.com>, Jonathan Cameron
	<Jonathan.Cameron@...wei.com>
Subject: Re: [PATCH v14 02/22] sfc: add cxl support

On Thu, May 08, 2025 at 01:41:15PM +0100, Alejandro Lucero Palau wrote:
> 
> On 5/8/25 01:33, Alison Schofield wrote:
> > On Thu, Apr 17, 2025 at 10:29:05PM +0100, alejandro.lucero-palau@....com wrote:
> > > From: Alejandro Lucero <alucerop@....com>
> > > 
> > > Add CXL initialization based on new CXL API for accel drivers and make
> > > it dependent on kernel CXL configuration.
> > > 
> > > Signed-off-by: Alejandro Lucero <alucerop@....com>
> > > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> > > ---
> > >   drivers/net/ethernet/sfc/Kconfig      |  9 +++++
> > >   drivers/net/ethernet/sfc/Makefile     |  1 +
> > >   drivers/net/ethernet/sfc/efx.c        | 15 +++++++-
> > >   drivers/net/ethernet/sfc/efx_cxl.c    | 55 +++++++++++++++++++++++++++
> > >   drivers/net/ethernet/sfc/efx_cxl.h    | 40 +++++++++++++++++++
> > >   drivers/net/ethernet/sfc/net_driver.h | 10 +++++
> > >   6 files changed, 129 insertions(+), 1 deletion(-)
> > >   create mode 100644 drivers/net/ethernet/sfc/efx_cxl.c
> > >   create mode 100644 drivers/net/ethernet/sfc/efx_cxl.h
> > > 
> > > diff --git a/drivers/net/ethernet/sfc/Kconfig b/drivers/net/ethernet/sfc/Kconfig
> > > index c4c43434f314..979f2801e2a8 100644
> > > --- a/drivers/net/ethernet/sfc/Kconfig
> > > +++ b/drivers/net/ethernet/sfc/Kconfig
> > > @@ -66,6 +66,15 @@ config SFC_MCDI_LOGGING
> > >   	  Driver-Interface) commands and responses, allowing debugging of
> > >   	  driver/firmware interaction.  The tracing is actually enabled by
> > >   	  a sysfs file 'mcdi_logging' under the PCI device.
> > > +config SFC_CXL
> > > +	bool "Solarflare SFC9100-family CXL support"
> > > +	depends on SFC && CXL_BUS >= SFC
> > > +	default SFC
> > > +	help
> > > +	  This enables SFC CXL support if the kernel is configuring CXL for
> > > +	  using CTPIO with CXL.mem. The SFC device with CXL support and
> > > +	  with a CXL-aware firmware can be used for minimizing latencies
> > > +	  when sending through CTPIO.
> > SFC is a tristate, and this new bool SFC_CXL defaults to it.
> > default y seems more obvious and follows convention in this Kconfig
> > file.
> > 
> > CXL_BUS >= SFC tripped me up in my testing where I had CXL_BUS M
> > and SFC Y. Why is that not allowable?
> > 
> > 
> 
> Not sure what you mean here. This means that if SFC can only be a module if
> CXL_BUS is a module and you want CXL with SFC.
> 
> You can have SFC as built-in in that case but without CXL support.

OK - get the desired constraint.

Why use >= with the tristates and why default to the tristate instead of
'y' - like this:

	depends on CXL_BUS
	depends on (SFC = m) || (SFC = y && CXL_BUS = y)
	default y