From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
"Derrick, Jonathan" <jonathan.derrick@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"joro@8bytes.org" <joro@8bytes.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"bhelgaas@google.com" <bhelgaas@google.com>,
"dwmw2@infradead.org" <dwmw2@infradead.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/5] PCI/vmd: Stop overriding dma_map_ops
Date: Thu, 29 Aug 2019 16:14:53 +0200 [thread overview]
Message-ID: <20190829141453.GC18677@lst.de> (raw)
In-Reply-To: <20190828150106.GD23412@localhost.localdomain>
On Wed, Aug 28, 2019 at 09:01:06AM -0600, Keith Busch wrote:
> On Wed, Aug 28, 2019 at 07:14:42AM -0700, Christoph Hellwig wrote:
> > With a little tweak to the intel-iommu code we should be able to work
> > around the VMD mess for the requester IDs without having to create giant
> > amounts of boilerplate DMA ops wrapping code. The other advantage of
> > this scheme is that we can respect the real DMA masks for the actual
> > devices, and I bet it will only be a matter of time until we'll see the
> > first DMA challeneged NVMe devices.
>
> This tests out fine on VMD hardware, but it's quite different than the
> previous patch. In v1, the original dev was used in iommu_need_mapping(),
> but this time it's the vmd device. Is this still using the actual device's
> DMA mask then?
True. But then again I think the old one was broken as well, as it
will pass the wrong dev to identity_mapping() or
iommu_request_dma_domain_for_dev. So I guess I'll need to respin it
a bit to do the work in iommu_need_mapping again, and then factor
that one to make it obvious what device we deal with.
next prev parent reply other threads:[~2019-08-29 14:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-28 14:14 stop overriding dma_ops in vmd v2 Christoph Hellwig
2019-08-28 14:14 ` [PATCH 1/5] x86/pci: Remove an ifdef __KERNEL__ from pci.h Christoph Hellwig
2019-08-28 14:14 ` [PATCH 2/5] x86/pci: Add a to_pci_sysdata helper Christoph Hellwig
2019-08-28 16:41 ` Derrick, Jonathan
2019-08-29 14:13 ` hch
2019-08-28 14:14 ` [PATCH 3/5] x86/pci: Replace the vmd_domain field with a vmd_dev pointer Christoph Hellwig
2019-08-28 14:14 ` [PATCH 4/5] PCI/vmd: Stop overriding dma_map_ops Christoph Hellwig
2019-08-28 15:01 ` Keith Busch
2019-08-29 14:14 ` Christoph Hellwig [this message]
2019-08-28 14:14 ` [PATCH 5/5] x86/pci: Remove X86_DEV_DMA_OPS Christoph Hellwig
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