From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH v7 2/6] iommu/dma: Add support for non-strict mode Date: Tue, 18 Sep 2018 18:10:07 +0100 Message-ID: <20180918171007.GJ16498@arm.com> References: <0a891cec4bb164f8cf2f57c753791a7d1f5f1d81.1536935328.git.robin.murphy@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <0a891cec4bb164f8cf2f57c753791a7d1f5f1d81.1536935328.git.robin.murphy@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Robin Murphy Cc: joro@8bytes.org, thunder.leizhen@huawei.com, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxarm@huawei.com, guohanjun@huawei.com, huawei.libin@huawei.com, john.garry@huawei.com List-Id: iommu@lists.linux-foundation.org Hi Robin, On Fri, Sep 14, 2018 at 03:30:20PM +0100, Robin Murphy wrote: > From: Zhen Lei > > 1. Save the related domain pointer in struct iommu_dma_cookie, make iovad > capable call domain->ops->flush_iotlb_all to flush TLB. > 2. During the iommu domain initialization phase, base on domain->non_strict > field to check whether non-strict mode is supported or not. If so, call > init_iova_flush_queue to register iovad->flush_cb callback. > 3. All unmap(contains iova-free) APIs will finally invoke __iommu_dma_unmap > -->iommu_dma_free_iova. If the domain is non-strict, call queue_iova to > put off iova freeing, and omit iommu_tlb_sync operation. Hmm, this is basically just a commentary on the code. Please could you write it more in terms of the problem that's being solved? > Signed-off-by: Zhen Lei > [rm: convert raw boolean to domain attribute] > Signed-off-by: Robin Murphy > --- > drivers/iommu/dma-iommu.c | 29 ++++++++++++++++++++++++++++- > include/linux/iommu.h | 1 + > 2 files changed, 29 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 511ff9a1d6d9..092e6926dc3c 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -55,6 +55,9 @@ struct iommu_dma_cookie { > }; > struct list_head msi_page_list; > spinlock_t msi_lock; > + > + /* Only be assigned in non-strict mode, otherwise it's NULL */ > + struct iommu_domain *domain; > }; > > static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie) > @@ -257,6 +260,17 @@ static int iova_reserve_iommu_regions(struct device *dev, > return ret; > } > > +static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad) > +{ > + struct iommu_dma_cookie *cookie; > + struct iommu_domain *domain; > + > + cookie = container_of(iovad, struct iommu_dma_cookie, iovad); > + domain = cookie->domain; > + > + domain->ops->flush_iotlb_all(domain); Can we rely on this function pointer being non-NULL? I think it would be better to call iommu_flush_tlb_all(cookie->domain) instead. > +} > + > /** > * iommu_dma_init_domain - Initialise a DMA mapping domain > * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() > @@ -275,6 +289,7 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, > struct iommu_dma_cookie *cookie = domain->iova_cookie; > struct iova_domain *iovad = &cookie->iovad; > unsigned long order, base_pfn, end_pfn; > + int attr = 1; Do we actually need to initialise this? Will