From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stanislaw Gruszka Subject: Re: [PATCH] iommu/amd: fix sg->dma_address for sg->offset bigger than PAGE_SIZE Date: Tue, 12 Mar 2019 08:08:33 +0100 Message-ID: <20190312070832.GA2483@redhat.com> References: <20190226112407.GB2989@redhat.com> <20190228090411.GA24938@redhat.com> <20190228104223.GA2749@redhat.com> <20190228121948.GD6072@redhat.com> <20190228134029.GC1594@8bytes.org> <20190304071037.GA2787@redhat.com> <20190311084319.GA3310@redhat.com> <20190311090314.GB3310@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Alexander Duyck Cc: Rosen Penev , Joerg Roedel , Lorenzo Bianconi , linux-wireless , Samuel Sieb , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, jan.viktorin@gmail.com List-Id: iommu@lists.linux-foundation.org On Mon, Mar 11, 2019 at 08:47:44AM -0700, Alexander Duyck wrote: > > drivers/iommu/amd_iommu.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c > > index 6b0760dafb3e..949621f33624 100644 > > --- a/drivers/iommu/amd_iommu.c > > +++ b/drivers/iommu/amd_iommu.c > > @@ -2604,7 +2604,7 @@ static int map_sg(struct device *dev, struct scatterlist *sglist, > > > > /* Everything is mapped - write the right values into s->dma_address */ > > for_each_sg(sglist, s, nelems, i) { > > - s->dma_address += address + s->offset; > > + s->dma_address += address + (s->offset & ~PAGE_MASK); > > s->dma_length = s->length; > > } > > > > You should add a comment calling out that this is needed because the > sg_phys(s) call above this is masked with PAGE_MASK. Then this makes > much more sense. Otherwise I would have assumed you needed either the > full offset or none. Would something like this /* * Everything is mapped - write the right values into s->dma_address. * Take into account s->offset can be bigger than page size and sg_phys(s) * address has to be aligned to page granularity. */ be appropriate ? Stanislaw From mboxrd@z Thu Jan 1 00:00:00 1970 From: sgruszka@redhat.com (Stanislaw Gruszka) Date: Tue, 12 Mar 2019 08:08:33 +0100 Subject: [PATCH] iommu/amd: fix sg->dma_address for sg->offset bigger than PAGE_SIZE In-Reply-To: References: <20190226112407.GB2989@redhat.com> <20190228090411.GA24938@redhat.com> <20190228104223.GA2749@redhat.com> <20190228121948.GD6072@redhat.com> <20190228134029.GC1594@8bytes.org> <20190304071037.GA2787@redhat.com> <20190311084319.GA3310@redhat.com> <20190311090314.GB3310@redhat.com> Message-ID: <20190312070832.GA2483@redhat.com> On Mon, Mar 11, 2019@08:47:44AM -0700, Alexander Duyck wrote: > > drivers/iommu/amd_iommu.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c > > index 6b0760dafb3e..949621f33624 100644 > > --- a/drivers/iommu/amd_iommu.c > > +++ b/drivers/iommu/amd_iommu.c > > @@ -2604,7 +2604,7 @@ static int map_sg(struct device *dev, struct scatterlist *sglist, > > > > /* Everything is mapped - write the right values into s->dma_address */ > > for_each_sg(sglist, s, nelems, i) { > > - s->dma_address += address + s->offset; > > + s->dma_address += address + (s->offset & ~PAGE_MASK); > > s->dma_length = s->length; > > } > > > > You should add a comment calling out that this is needed because the > sg_phys(s) call above this is masked with PAGE_MASK. Then this makes > much more sense. Otherwise I would have assumed you needed either the > full offset or none. Would something like this /* * Everything is mapped - write the right values into s->dma_address. * Take into account s->offset can be bigger than page size and sg_phys(s) * address has to be aligned to page granularity. */ be appropriate ? Stanislaw