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From: Jakub Kicinski <kuba@kernel.org>
To: Dragos Tatulea <dtatulea@nvidia.com>
Cc: <almasrymina@google.com>, <asml.silence@gmail.com>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
	Saeed Mahameed <saeedm@nvidia.com>, <tariqt@nvidia.com>,
	<cratiu@nvidia.com>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [RFC net-next 1/4] net: Allow non parent devices to be used for ZC DMA
Date: Wed, 2 Jul 2025 11:32:08 -0700	[thread overview]
Message-ID: <20250702113208.5adafe79@kernel.org> (raw)
In-Reply-To: <20250702172433.1738947-2-dtatulea@nvidia.com>

On Wed, 2 Jul 2025 20:24:23 +0300 Dragos Tatulea wrote:
> For zerocopy (io_uring, devmem), there is an assumption that the
> parent device can do DMA. However that is not always the case:
> for example mlx5 SF devices have an auxiliary device as a parent.

Noob question -- I thought that the point of SFs was that you can pass
them thru to a VM. How do they not have DMA support? Is it added on
demand by the mediated driver or some such?

  reply	other threads:[~2025-07-02 18:32 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-02 17:24 [RFC net-next 0/4] devmem/io_uring: Allow devices without parent PCI device Dragos Tatulea
2025-07-02 17:24 ` [RFC net-next 1/4] net: Allow non parent devices to be used for ZC DMA Dragos Tatulea
2025-07-02 18:32   ` Jakub Kicinski [this message]
2025-07-02 20:01     ` Dragos Tatulea
2025-07-02 20:53       ` Jakub Kicinski
2025-07-03 11:58         ` Parav Pandit
2025-07-04 13:11           ` Dragos Tatulea
2025-07-07 18:44             ` Mina Almasry
2025-07-07 21:35               ` Dragos Tatulea
2025-07-07 21:55                 ` Mina Almasry
2025-07-08  8:52                   ` Parav Pandit
2025-07-08 10:47                   ` Pavel Begunkov
2025-07-08 14:23                   ` Dragos Tatulea
2025-07-08 11:08             ` Pavel Begunkov
2025-07-08 14:26               ` Dragos Tatulea
2025-07-10 23:58           ` Jakub Kicinski
2025-07-11  2:52             ` Parav Pandit
2025-07-11 13:51               ` Jakub Kicinski
2025-07-08 11:06   ` Pavel Begunkov
2025-07-08 14:10     ` Mina Almasry
2025-07-08 15:25       ` Pavel Begunkov
2025-07-02 17:24 ` [RFC net-next 2/4] io_uring/zcrx: Use the new netdev_get_dma_dev() API Dragos Tatulea
2025-07-02 17:24 ` [RFC net-next 3/4] net: devmem: " Dragos Tatulea
2025-07-02 17:24 ` [RFC net-next 4/4] net/mlx5e: Enable HDS zerocopy flows for SFs Dragos Tatulea

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