From: Jakub Kicinski <kuba@kernel•org>
To: Ratheesh Kannoth <rkannoth@marvell•com>
Cc: <linux-kernel@vger•kernel.org>, <netdev@vger•kernel.org>,
<andrew+netdev@lunn•ch>, <davem@davemloft•net>,
<donald.hunter@gmail•com>, <edumazet@google•com>,
<horms@kernel•org>, <jiri@resnulli•us>, <pabeni@redhat•com>,
<sgoutham@marvell•com>
Subject: Re: [PATCH v19 net-next 1/9] octeontx2-af: Enforce single RVU AF probe
Date: Mon, 8 Jun 2026 19:41:51 -0700 [thread overview]
Message-ID: <20260608194151.7535b2f7@kernel.org> (raw)
In-Reply-To: <aid55liiG7bcuZ3f@rkannoth-OptiPlex-7090>
On Tue, 9 Jun 2026 07:56:46 +0530 Ratheesh Kannoth wrote:
> > > The comparison to a generic PCI networking driver isn't quite applicable
> > > here. The RVU AF (Administrative Function) is not a standard NIC PF —
> > > it is a system-level resource manager that owns a single, shared set of
> > > AF registers across the entire RVU subsystem. The hardware spec is
> > > explicit on this: "RVU has a single, common set of AF registers.
> > >
> > > This is fundamentally different from a multi-port NIC where each PF is
> > > an independent, symmetric instance. In the RVU model, there is exactly
> > > one AF device per SoC, and all other PFs communicate with it
> > > via mailboxes rather than accessing AF registers directly. Allowing a
> > > second AF probe would mean two driver instances racing to manage the
> > > same global hardware state — provisioning LFs, configuring
> > > NPC/NIX/NPA — with no hardware arbitration between them.
> >
> > I asked you before - is this a driver for a PCIe devices?
> > You said "yes". If so what prevents the user from plugging two such
> > devices into one system?
>
> The RVU AF (PCI device ID 0xA065) is not a pluggable add-in card. It
> is an integrated function inside the Marvell OcteonTX2/CN10K/CN20K SoC.
> On-chip firmware programs the PCI configuration space for all RVU
> functions at boot time — setting device ID, class code, and BAR layout
> via RVU_PRIV_PF()_ID_CFG — and the Linux PCI subsystem then discovers
> what firmware has configured. There is no slot, no connector, and no
> mechanism by which a second instance of this device could appear on the
> same system. The hardware exposes exactly one AF PCI device per SoC,
> and that is the only device this driver (rvu af driver) binds to.
SMH, I asked you if it is a PCIe **card** or a SoC device.
You answered "This is PCIe." Now you're saying it's a function within
the SoC. I can see the driver is operating on struct pci_device...
Just say this is an integrated device within the SoC then in the commit
message.
next prev parent reply other threads:[~2026-06-09 2:41 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-05 6:32 [PATCH v19 net-next 0/9] octeontx2-af: npc: Enhancements Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 1/9] octeontx2-af: Enforce single RVU AF probe Ratheesh Kannoth
2026-06-08 2:17 ` Ratheesh Kannoth
2026-06-08 2:25 ` Ratheesh Kannoth
2026-06-08 22:40 ` Jakub Kicinski
2026-06-09 1:43 ` Ratheesh Kannoth
2026-06-09 2:02 ` Jakub Kicinski
2026-06-09 2:26 ` Ratheesh Kannoth
2026-06-09 2:41 ` Jakub Kicinski [this message]
2026-06-05 6:32 ` [PATCH v19 net-next 2/9] octeontx2-af: npc: cn20k: debugfs enhancements Ratheesh Kannoth
2026-06-08 2:20 ` Ratheesh Kannoth
2026-06-08 2:26 ` Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 3/9] devlink: heap-allocate param fill buffers in devlink_nl_param_fill Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 4/9] devlink: Implement devlink param multi attribute nested data values Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 5/9] octeontx2-af: npc: cn20k: add subbank search order control Ratheesh Kannoth
2026-06-08 2:22 ` Ratheesh Kannoth
2026-06-08 2:28 ` Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 6/9] octeontx2: cn20k: Coordinate default rules with NIX LF lifecycle Ratheesh Kannoth
2026-06-08 2:29 ` Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 7/9] octeontx2-af: npc: Support for custom KPU profile from filesystem Ratheesh Kannoth
2026-06-08 2:23 ` Ratheesh Kannoth
2026-06-08 2:30 ` Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 8/9] octeontx2: cn20k: Respect NPC MCAM X2/X4 profile in flows and DFT alloc Ratheesh Kannoth
2026-06-08 2:24 ` Ratheesh Kannoth
2026-06-08 2:31 ` Ratheesh Kannoth
2026-06-05 6:32 ` [PATCH v19 net-next 9/9] octeontx2-af: npc: cn20k: Allocate npc_priv and dstats dynamically Ratheesh Kannoth
2026-06-08 2:25 ` Ratheesh Kannoth
2026-06-08 2:32 ` Ratheesh Kannoth
-- strict thread matches above, loose matches on Subject: below --
2026-06-05 3:50 [PATCH v19 net-next 0/9] octeontx2-af: npc: Enhancements Ratheesh Kannoth
2026-06-05 3:50 ` [PATCH v19 net-next 1/9] octeontx2-af: Enforce single RVU AF probe Ratheesh Kannoth
2026-06-05 7:47 ` Ratheesh Kannoth
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