From: Robin Murphy <robin.murphy@arm.com> To: Nadav Amit <nadav.amit@gmail.com>, Joerg Roedel <joro@8bytes.org> Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Nadav Amit <namit@vmware.com>, Jiajun Cao <caojiajun@vmware.com>, Will Deacon <will@kernel.org> Subject: Re: [PATCH v3 6/6] iommu/amd: Sync once for scatter-gather operations Date: Tue, 15 Jun 2021 12:25:11 +0100 [thread overview] Message-ID: <99671205-134d-7563-63e2-b65c13d5d074@arm.com> (raw) In-Reply-To: <20210607182541.119756-7-namit@vmware.com> On 2021-06-07 19:25, Nadav Amit wrote: > From: Nadav Amit <namit@vmware.com> > > On virtual machines, software must flush the IOTLB after each page table > entry update. > > The iommu_map_sg() code iterates through the given scatter-gather list > and invokes iommu_map() for each element in the scatter-gather list, > which calls into the vendor IOMMU driver through iommu_ops callback. As > the result, a single sg mapping may lead to multiple IOTLB flushes. > > Fix this by adding amd_iotlb_sync_map() callback and flushing at this > point after all sg mappings we set. > > This commit is followed and inspired by commit 933fcd01e97e2 > ("iommu/vt-d: Add iotlb_sync_map callback"). > > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Will Deacon <will@kernel.org> > Cc: Jiajun Cao <caojiajun@vmware.com> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Lu Baolu <baolu.lu@linux.intel.com> > Cc: iommu@lists.linux-foundation.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Nadav Amit <namit@vmware.com> > --- > drivers/iommu/amd/iommu.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c > index 128f2e889ced..dd23566f1db8 100644 > --- a/drivers/iommu/amd/iommu.c > +++ b/drivers/iommu/amd/iommu.c > @@ -2027,6 +2027,16 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, > return ret; > } > > +static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom, > + unsigned long iova, size_t size) > +{ > + struct protection_domain *domain = to_pdomain(dom); > + struct io_pgtable_ops *ops = &domain->iop.iop.ops; > + > + if (ops->map) Not too critical since you're only moving existing code around, but is ops->map ever not set? Either way the check ends up looking rather out-of-place here :/ It's not very clear what the original intent was - I do wonder whether it's supposed to be related to PAGE_MODE_NONE, but given that amd_iommu_map() has an explicit check and errors out early in that case, we'd never get here anyway. Possibly something to come back and clean up later? Robin. > + domain_flush_np_cache(domain, iova, size); > +} > + > static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > phys_addr_t paddr, size_t page_size, int iommu_prot, > gfp_t gfp) > @@ -2045,10 +2055,8 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > if (iommu_prot & IOMMU_WRITE) > prot |= IOMMU_PROT_IW; > > - if (ops->map) { > + if (ops->map) > ret = ops->map(ops, iova, paddr, page_size, prot, gfp); > - domain_flush_np_cache(domain, iova, page_size); > - } > > return ret; > } > @@ -2249,6 +2257,7 @@ const struct iommu_ops amd_iommu_ops = { > .attach_dev = amd_iommu_attach_device, > .detach_dev = amd_iommu_detach_device, > .map = amd_iommu_map, > + .iotlb_sync_map = amd_iommu_iotlb_sync_map, > .unmap = amd_iommu_unmap, > .iova_to_phys = amd_iommu_iova_to_phys, > .probe_device = amd_iommu_probe_device, >
WARNING: multiple messages have this Message-ID (diff)
From: Robin Murphy <robin.murphy@arm.com> To: Nadav Amit <nadav.amit@gmail.com>, Joerg Roedel <joro@8bytes.org> Cc: Will Deacon <will@kernel.org>, iommu@lists.linux-foundation.org, Nadav Amit <namit@vmware.com>, linux-kernel@vger.kernel.org, Jiajun Cao <caojiajun@vmware.com> Subject: Re: [PATCH v3 6/6] iommu/amd: Sync once for scatter-gather operations Date: Tue, 15 Jun 2021 12:25:11 +0100 [thread overview] Message-ID: <99671205-134d-7563-63e2-b65c13d5d074@arm.com> (raw) In-Reply-To: <20210607182541.119756-7-namit@vmware.com> On 2021-06-07 19:25, Nadav Amit wrote: > From: Nadav Amit <namit@vmware.com> > > On virtual machines, software must flush the IOTLB after each page table > entry update. > > The iommu_map_sg() code iterates through the given scatter-gather list > and invokes iommu_map() for each element in the scatter-gather list, > which calls into the vendor IOMMU driver through iommu_ops callback. As > the result, a single sg mapping may lead to multiple IOTLB flushes. > > Fix this by adding amd_iotlb_sync_map() callback and flushing at this > point after all sg mappings we set. > > This commit is followed and inspired by commit 933fcd01e97e2 > ("iommu/vt-d: Add iotlb_sync_map callback"). > > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Will Deacon <will@kernel.org> > Cc: Jiajun Cao <caojiajun@vmware.com> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Lu Baolu <baolu.lu@linux.intel.com> > Cc: iommu@lists.linux-foundation.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Nadav Amit <namit@vmware.com> > --- > drivers/iommu/amd/iommu.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c > index 128f2e889ced..dd23566f1db8 100644 > --- a/drivers/iommu/amd/iommu.c > +++ b/drivers/iommu/amd/iommu.c > @@ -2027,6 +2027,16 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, > return ret; > } > > +static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom, > + unsigned long iova, size_t size) > +{ > + struct protection_domain *domain = to_pdomain(dom); > + struct io_pgtable_ops *ops = &domain->iop.iop.ops; > + > + if (ops->map) Not too critical since you're only moving existing code around, but is ops->map ever not set? Either way the check ends up looking rather out-of-place here :/ It's not very clear what the original intent was - I do wonder whether it's supposed to be related to PAGE_MODE_NONE, but given that amd_iommu_map() has an explicit check and errors out early in that case, we'd never get here anyway. Possibly something to come back and clean up later? Robin. > + domain_flush_np_cache(domain, iova, size); > +} > + > static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > phys_addr_t paddr, size_t page_size, int iommu_prot, > gfp_t gfp) > @@ -2045,10 +2055,8 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, > if (iommu_prot & IOMMU_WRITE) > prot |= IOMMU_PROT_IW; > > - if (ops->map) { > + if (ops->map) > ret = ops->map(ops, iova, paddr, page_size, prot, gfp); > - domain_flush_np_cache(domain, iova, page_size); > - } > > return ret; > } > @@ -2249,6 +2257,7 @@ const struct iommu_ops amd_iommu_ops = { > .attach_dev = amd_iommu_attach_device, > .detach_dev = amd_iommu_detach_device, > .map = amd_iommu_map, > + .iotlb_sync_map = amd_iommu_iotlb_sync_map, > .unmap = amd_iommu_unmap, > .iova_to_phys = amd_iommu_iova_to_phys, > .probe_device = amd_iommu_probe_device, > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-06-15 11:25 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-07 18:25 [PATCH v3 0/6] iommu/amd: Enable page-selective flushes Nadav Amit 2021-06-07 18:25 ` Nadav Amit 2021-06-07 18:25 ` [PATCH v3 1/6] iommu/amd: Selective flush on unmap Nadav Amit 2021-06-07 18:25 ` Nadav Amit 2021-06-07 18:25 ` [PATCH v3 2/6] iommu/amd: Do not use flush-queue when NpCache is on Nadav Amit 2021-06-07 18:25 ` Nadav Amit 2021-06-15 13:08 ` Robin Murphy 2021-06-15 13:08 ` Robin Murphy 2021-06-15 18:26 ` Nadav Amit 2021-06-15 18:26 ` Nadav Amit 2021-06-15 19:36 ` Robin Murphy 2021-06-15 19:36 ` Robin Murphy 2021-06-07 18:25 ` [PATCH v3 3/6] iommu: Improve iommu_iotlb_gather helpers Nadav Amit 2021-06-07 18:25 ` Nadav Amit 2021-06-11 13:50 ` Will Deacon 2021-06-11 13:50 ` Will Deacon 2021-06-15 10:42 ` Robin Murphy 2021-06-15 10:42 ` Robin Murphy 2021-06-15 19:05 ` Nadav Amit 2021-06-15 19:05 ` Nadav Amit 2021-06-15 19:07 ` Nadav Amit 2021-06-15 19:07 ` Nadav Amit 2021-06-15 12:29 ` Yong Wu 2021-06-15 12:29 ` Yong Wu 2021-06-15 12:41 ` Robin Murphy 2021-06-15 12:41 ` Robin Murphy 2021-06-07 18:25 ` [PATCH v3 4/6] iommu: Factor iommu_iotlb_gather_is_disjoint() out Nadav Amit 2021-06-07 18:25 ` Nadav Amit 2021-06-11 13:57 ` Will Deacon 2021-06-11 13:57 ` Will Deacon 2021-06-11 16:50 ` Nadav Amit 2021-06-11 16:50 ` Nadav Amit 2021-06-15 10:29 ` Will Deacon 2021-06-15 10:29 ` Will Deacon 2021-06-15 18:54 ` Nadav Amit 2021-06-15 18:54 ` Nadav Amit 2021-06-07 18:25 ` [PATCH v3 5/6] iommu/amd: Tailored gather logic for AMD Nadav Amit 2021-06-07 18:25 ` Nadav Amit 2021-06-15 12:55 ` Robin Murphy 2021-06-15 12:55 ` Robin Murphy 2021-06-15 18:14 ` Nadav Amit 2021-06-15 18:14 ` Nadav Amit 2021-06-15 19:20 ` Robin Murphy 2021-06-15 19:20 ` Robin Murphy 2021-06-15 19:46 ` Nadav Amit 2021-06-15 19:46 ` Nadav Amit 2021-06-07 18:25 ` [PATCH v3 6/6] iommu/amd: Sync once for scatter-gather operations Nadav Amit 2021-06-07 18:25 ` Nadav Amit 2021-06-15 11:25 ` Robin Murphy [this message] 2021-06-15 11:25 ` Robin Murphy 2021-06-15 18:51 ` Nadav Amit 2021-06-15 18:51 ` Nadav Amit
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