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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Christoph Hellwig <hch@lst.de>,
	Christoph Hellwig <hch@infradead.org>,
	linux-kernel@vger.kernel.org
Subject: Re: ehci-pci breakage with dma-mapping changes in 5.4-rc2
Date: Mon, 7 Oct 2019 19:54:02 -0400	[thread overview]
Message-ID: <20191007235401.GA608824@rani.riverdale.lan> (raw)
In-Reply-To: <20191007221054.GA409402@rani.riverdale.lan>

On Mon, Oct 07, 2019 at 06:10:55PM -0400, Arvind Sankar wrote:
> On Mon, Oct 07, 2019 at 08:47:54PM +0200, Christoph Hellwig wrote:
> > On Mon, Oct 07, 2019 at 02:32:07PM -0400, Arvind Sankar wrote:
> > > On Mon, Oct 07, 2019 at 01:58:57PM -0400, Arvind Sankar wrote:
> > > > On Mon, Oct 07, 2019 at 10:56:30AM -0700, Christoph Hellwig wrote:
> > > > > On Mon, Oct 07, 2019 at 07:55:28PM +0200, Christoph Hellwig wrote:
> > > > > > On Mon, Oct 07, 2019 at 01:54:32PM -0400, Arvind Sankar wrote:
> > > > > > > It doesn't boot with the patch. Won't it go
> > > > > > > 	dma_get_required_mask
> > > > > > > 	-> intel_get_required_mask
> > > > > > > 	-> iommu_need_mapping
> > > > > > > 	-> dma_get_required_mask
> > > > > > > ?
> > > > > > > 
> > > > > > > Should the call to dma_get_required_mask in iommu_need_mapping be
> > > > > > > replaced with dma_direct_get_required_mask on top of your patch?
> > > > > > 
> > > > > > Yes, sorry.
> > > > > 
> > > > > Actually my patch already calls dma_direct_get_required_mask.
> > > > > How did you get the loop?
> > > > 
> > > > The function iommu_need_mapping (not changed by your patch) calls
> > > > dma_get_required_mask internally, to check whether the device's dma_mask
> > > > is big enough or not. That's the call I was asking whether it needs to
> > > > be changed.
> > > 
> > > Yeah the attached patch seems to fix it.
> > 
> > That looks fine to me:
> > 
> > Acked-by: Christoph Hellwig <hch@lst.de>
> 
> Do you want me to resend the patch as its own mail, or do you just take
> it with a Tested-by: from me? If the former, I assume you're ok with me
> adding your Signed-off-by?
> 
> Thanks

A question on the original change though -- what happens if a single
device (or a single IOMMU domain really) does want >4G DMA address
space? Was that not previously allowed either?

  reply	other threads:[~2019-10-07 23:54 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-07  2:24 ehci-pci breakage with dma-mapping changes in 5.4-rc2 Arvind Sankar
2019-10-07  7:34 ` Christoph Hellwig
2019-10-07 17:54   ` Arvind Sankar
2019-10-07 17:55     ` Christoph Hellwig
2019-10-07 17:56       ` Christoph Hellwig
2019-10-07 17:58         ` Arvind Sankar
2019-10-07 18:32           ` Arvind Sankar
2019-10-07 18:47             ` Christoph Hellwig
2019-10-07 22:10               ` Arvind Sankar
2019-10-07 23:54                 ` Arvind Sankar [this message]
2019-10-08  7:32                   ` Christoph Hellwig
2019-10-08 11:51                     ` Arvind Sankar
2019-10-08 12:50                       ` Christoph Hellwig
2019-10-08 15:47                       ` Arvind Sankar
2019-10-09  6:50                         ` Christoph Hellwig
2019-10-09 13:48                           ` Arvind Sankar
2019-10-08  7:29                 ` Christoph Hellwig
2019-10-08 14:33                   ` [PATCH] iommu/vt-d: Return the correct dma mask when we are bypassing the IOMMU Arvind Sankar
2019-10-09  2:45                     ` Lu Baolu
2019-10-09  6:51                       ` Christoph Hellwig
2019-10-10  1:24                         ` Lu Baolu
2019-10-10  1:26                     ` Lu Baolu
2019-10-16 19:15                       ` Arvind Sankar
2019-10-17  7:08                         ` Christoph Hellwig
2019-10-17 15:55                           ` Arvind Sankar
2019-10-18  9:50                           ` Joerg Roedel
2019-10-18 15:14                             ` Christoph Hellwig
2019-10-18 15:21                               ` Joerg Roedel
2019-10-18 15:22                                 ` Christoph Hellwig

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