From: Christoph Hellwig <hch@infradead.org>
To: Kelly Devilliv <kelly.devilliv@outlook.com>
Cc: "Christian König" <christian.koenig@amd.com>,
"Robin Murphy" <robin.murphy@arm.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"will@kernel.org" <will@kernel.org>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: dma_map_resource() has a bad performance in pcie peer to peer transactions when iommu enabled in Linux
Date: Sun, 1 Oct 2023 23:30:12 -0700 [thread overview]
Message-ID: <ZRpjdPC4eSCA/jOk@infradead.org> (raw)
In-Reply-To: <TY2PR0101MB3136A7480B842E009BCBDA8384C3A@TY2PR0101MB3136.apcprd01.prod.exchangelabs.com>
FYI, dma_map_resources must never be used for PCIe P2P mappings, you
absolutely must use dma_map_sg as only that handles all the corner cases
correctly.
And we need to figure out a way to put a check into dma_map_resources
so that people stop abusing it.
next prev parent reply other threads:[~2023-10-02 6:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-26 15:30 dma_map_resource() has a bad performance in pcie peer to peer transactions when iommu enabled in Linux Kelly Devilliv
2023-10-02 6:30 ` Christoph Hellwig [this message]
2023-10-02 20:08 ` Robin Murphy
2023-10-04 6:26 ` Christian König
-- strict thread matches above, loose matches on Subject: below --
2023-09-25 14:17 Kelly Devilliv
2023-09-25 17:58 ` Christian König
2023-09-25 3:59 Kelly Devilliv
2023-09-25 11:15 ` Robin Murphy
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