From mboxrd@z Thu Jan 1 00:00:00 1970 From: robin.murphy@arm.com (Robin Murphy) Date: Tue, 6 Dec 2016 17:36:34 +0000 Subject: [RFC v3 05/10] iommu: Do not map reserved regions In-Reply-To: <1479215363-2898-6-git-send-email-eric.auger@redhat.com> References: <1479215363-2898-1-git-send-email-eric.auger@redhat.com> <1479215363-2898-6-git-send-email-eric.auger@redhat.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 15/11/16 13:09, Eric Auger wrote: > As we introduced IOMMU_RESV_NOMAP and IOMMU_RESV_MSI regions, > let's prevent those new regions from being mapped. > > Signed-off-by: Eric Auger > --- > drivers/iommu/iommu.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 6ee529f..a4530ad 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -343,6 +343,9 @@ static int iommu_group_create_direct_mappings(struct iommu_group *group, > start = ALIGN(entry->start, pg_size); > end = ALIGN(entry->start + entry->length, pg_size); > > + if (entry->prot & IOMMU_RESV_MASK) This seems to be the only place that this mask is used, and frankly I think it's less clear than simply "(IOMMU_RESV_NOMAP | IOMMU_RESV_MSI)" would be, at which point we may as well drop the mask and special value trickery altogether. Plus, per my previous comment, if it were to be "if (entry->type != )" instead, that's about as obvious as it can get. Robin. > + continue; > + > for (addr = start; addr < end; addr += pg_size) { > phys_addr_t phys_addr; > >