From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH 2/2] iommu/dma: Respect IOMMU aperture when allocating Date: Tue, 9 Aug 2016 17:36:02 +0200 Message-ID: <20160809153602.GD29650@8bytes.org> References: <3feb8016c2def4aabc5513b548e17bbf57c27959.1470755555.git.robin.murphy@arm.com> <6d73ab5fb671089057b31beb73667c09147a0f0e.1470755555.git.robin.murphy@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <6d73ab5fb671089057b31beb73667c09147a0f0e.1470755555.git.robin.murphy-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Robin Murphy Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Tue, Aug 09, 2016 at 04:23:18PM +0100, Robin Murphy wrote: > Where a device driver has set a 64-bit DMA mask to indicate the absence > of addressing limitations, we still need to ensure that we don't > allocate IOVAs beyond the actual input size of the IOMMU. The reported > aperture is the most reliable way we have of inferring that input > address size, so use that to enforce a hard upper limit. > > Signed-off-by: Robin Murphy Also missing 'Fixes:' line. > --- > > This is the only other thing I currently have which could perhaps be > considered a fix; otherwise I'll pull it into the PCI/SMMU series. > > drivers/iommu/dma-iommu.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 7d991c81c4fa..092d781f5f35 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -158,6 +158,8 @@ static struct iova *__alloc_iova(struct iova_domain *iovad, size_t size, > unsigned long shift = iova_shift(iovad); > unsigned long length = iova_align(iovad, size) >> shift; > > + if (domain->geometry.force_aperture) > + dma_limit &= domain->geometry.aperture_end; This might work, but is misleading as limits and aperture_end are neither a mask nor a bitfield. It is more descriptive to use min() here: dma_limit = min(dma_limit, omain->geometry.aperture_end);