On Mon, Jun 17, 2024 at 6:42 AM Andre Przywara <andre.przywara@xxxxxxx> wrote: > > The Allwinner IOMMU is a strict 32-bit device, with its input addresses, > the page table root pointer as well as both level's page tables and also > the target addresses all required to be below 4GB. > The Allwinner H6 SoC only supports 32-bit worth of physical addresses > anyway, so this isn't a problem so far, but the H616 and later SoCs extend > the PA space beyond 32 bit to accommodate more DRAM. > To make sure we stay within the 32-bit PA range required by the IOMMU, > force the memory for the page tables to come from below 4GB. by using > allocations with the DMA32 flag. > Also reject any attempt to map target addresses beyond 4GB, and print a > warning to give users a hint while this fails. > > Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx> > --- > drivers/iommu/sun50i-iommu.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c > index dd3f07384624c..20a07f829085d 100644 > --- a/drivers/iommu/sun50i-iommu.c > +++ b/drivers/iommu/sun50i-iommu.c > @@ -602,6 +602,14 @@ static int sun50i_iommu_map(struct iommu_domain *domain, unsigned long iova, > u32 *page_table, *pte_addr; > int ret = 0; > > + /* the IOMMU can only handle 32-bit addresses, both input and output */ > + if ((uint64_t)paddr >> 32) { > + ret = -EINVAL; > + dev_warn_once(iommu->dev, > + "attempt to map address beyond 4GB\n"); > + goto out; > + } > + > page_table = sun50i_dte_get_page_table(sun50i_domain, iova, gfp); > if (IS_ERR(page_table)) { > ret = PTR_ERR(page_table); > @@ -682,7 +690,8 @@ sun50i_iommu_domain_alloc_paging(struct device *dev) > if (!sun50i_domain) > return NULL; > > - sun50i_domain->dt = iommu_alloc_pages(GFP_KERNEL, get_order(DT_SIZE)); > + sun50i_domain->dt = iommu_alloc_pages(GFP_KERNEL | GFP_DMA32, > + get_order(DT_SIZE)); > if (!sun50i_domain->dt) > goto err_free_domain; > > @@ -997,7 +1006,7 @@ static int sun50i_iommu_probe(struct platform_device *pdev) > > iommu->pt_pool = kmem_cache_create(dev_name(&pdev->dev), > PT_SIZE, PT_SIZE, > - SLAB_HWCACHE_ALIGN, > + SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA32, > NULL); > if (!iommu->pt_pool) > return -ENOMEM; > -- > 2.39.4 >