Hi Jean,
On 6/10/21 9:51 AM, Jean-Philippe Brucker wrote:
> Passing a 64-bit address width to iommu_setup_dma_ops() is valid on
> virtual platforms, but isn't currently possible. The overflow check in
> iommu_dma_init_domain() prevents this even when @dma_base isn't 0. Pass
> a limit address instead of a size, so callers don't have to fake a size
> to work around the check.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> ---
> include/linux/dma-iommu.h | 4 ++--
> arch/arm64/mm/dma-mapping.c | 2 +-
> drivers/iommu/amd/iommu.c | 2 +-
> drivers/iommu/dma-iommu.c | 12 ++++++------
> drivers/iommu/intel/iommu.c | 2 +-
> 5 files changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
> index 6e75a2d689b4..758ca4694257 100644
> --- a/include/linux/dma-iommu.h
> +++ b/include/linux/dma-iommu.h
> @@ -19,7 +19,7 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base);
> void iommu_put_dma_cookie(struct iommu_domain *domain);
>
> /* Setup call for arch DMA mapping code */
> -void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size);
> +void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit);
>
> /* The DMA API isn't _quite_ the whole story, though... */
> /*
> @@ -50,7 +50,7 @@ struct msi_msg;
> struct device;
>
> static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base,
> - u64 size)
> + u64 dma_limit)
> {
> }
>
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index 4bf1dd3eb041..7bd1d2199141 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -50,7 +50,7 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>
> dev->dma_coherent = coherent;
> if (iommu)
> - iommu_setup_dma_ops(dev, dma_base, size);
> + iommu_setup_dma_ops(dev, dma_base, size - dma_base - 1);
I don't get size - dma_base - 1?
>
> #ifdef CONFIG_XEN
> if (xen_swiotlb_detect())
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index 3ac42bbdefc6..94b96d81fcfd 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -1713,7 +1713,7 @@ static void amd_iommu_probe_finalize(struct device *dev)
> /* Domains are initialized for this device - have a look what we ended up with */
> domain = iommu_get_domain_for_dev(dev);
> if (domain->type == IOMMU_DOMAIN_DMA)
> - iommu_setup_dma_ops(dev, IOVA_START_PFN << PAGE_SHIFT, 0);
> + iommu_setup_dma_ops(dev, IOVA_START_PFN << PAGE_SHIFT, U64_MAX);
> else
> set_dma_ops(dev, NULL);
> }
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 7bcdd1205535..c62e19bed302 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -319,16 +319,16 @@ static bool dev_is_untrusted(struct device *dev)
> * iommu_dma_init_domain - Initialise a DMA mapping domain
> * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
> * @base: IOVA at which the mappable address space starts
> - * @size: Size of IOVA space
> + * @limit: Last address of the IOVA space
> * @dev: Device the domain is being initialised for
> *
> - * @base and @size should be exact multiples of IOMMU page granularity to
> + * @base and @limit + 1 should be exact multiples of IOMMU page granularity to
> * avoid rounding surprises. If necessary, we reserve the page at address 0
> * to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
> * any change which could make prior IOVAs invalid will fail.
> */
> static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
> - u64 size, struct device *dev)
> + dma_addr_t limit, struct device *dev)
> {
> struct iommu_dma_cookie *cookie = domain->iova_cookie;
> unsigned long order, base_pfn;
> @@ -346,7 +346,7 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
> /* Check the domain allows at least some access to the device... */
> if (domain->geometry.force_aperture) {
> if (base > domain->geometry.aperture_end ||
> - base + size <= domain->geometry.aperture_start) {
> + limit < domain->geometry.aperture_start) {
> pr_warn("specified DMA range outside IOMMU capability\n");
> return -EFAULT;
> }
> @@ -1308,7 +1308,7 @@ static const struct dma_map_ops iommu_dma_ops = {
> * The IOMMU core code allocates the default DMA domain, which the underlying
> * IOMMU driver needs to support via the dma-iommu layer.
> */
> -void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size)
> +void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit)
> {
> struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>
> @@ -1320,7 +1320,7 @@ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size)
> * underlying IOMMU driver needs to support via the dma-iommu layer.
> */
> if (domain->type == IOMMU_DOMAIN_DMA) {
> - if (iommu_dma_init_domain(domain, dma_base, size, dev))
> + if (iommu_dma_init_domain(domain, dma_base, dma_limit, dev))
> goto out_err;
> dev->dma_ops = &iommu_dma_ops;
> }
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index be35284a2016..85f18342603c 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5171,7 +5171,7 @@ static void intel_iommu_probe_finalize(struct device *dev)
>
> if (domain && domain->type == IOMMU_DOMAIN_DMA)
> iommu_setup_dma_ops(dev, base,
> - __DOMAIN_MAX_ADDR(dmar_domain->gaw) - base);
> + __DOMAIN_MAX_ADDR(dmar_domain->gaw));
> else
> set_dma_ops(dev, NULL);
> }
Thanks
Eric
