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[82.0.78.162]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48711693a08sm3571665e9.2.2026.03.23.15.18.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 23 Mar 2026 15:18:06 -0700 (PDT) Message-ID: <4d8eae17-3b95-4fba-82e3-1da6b53c0a1d@gmail.com> Date: Mon, 23 Mar 2026 22:18:05 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v24 11/11] sfc: support pio mapping based on cxl To: alejandro.lucero-palau@amd.com, linux-cxl@vger.kernel.org, netdev@vger.kernel.org, dave.jiang@intel.com, dan.j.williams@intel.com, edward.cree@amd.com, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com Cc: Alejandro Lucero , Jonathan Cameron References: <20260323113117.2352709-1-alejandro.lucero-palau@amd.com> <20260323113117.2352709-12-alejandro.lucero-palau@amd.com> Content-Language: en-GB From: Edward Cree In-Reply-To: <20260323113117.2352709-12-alejandro.lucero-palau@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 23/03/2026 11:31, alejandro.lucero-palau@amd.com wrote: > From: Alejandro Lucero > > A PIO buffer is a region of device memory to which the driver can write a > packet for TX, with the device handling the transmit doorbell without > requiring a DMA for getting the packet data, which helps reducing latency > in certain exchanges. With CXL mem protocol this latency can be lowered > further. > > With a device supporting CXL and successfully initialised, use the cxl > region to map the memory range and use this mapping for PIO buffers. > > Add the disabling of those CXL-based PIO buffers if the callback for > potential cxl endpoint removal by the CXL code happens. > > Signed-off-by: Alejandro Lucero > Reviewed-by: Jonathan Cameron > Reviewed-by: Dave Jiang Acked-by: Edward Cree