On Fri, Nov 04, 2016 at 11:24:06AM +0000, Eric Auger wrote:
> The function populates the list of reserved regions with the
> PCI host bridge windows and the MSI IOVA range.
>
> At the moment an arbitray MSI IOVA window is set at 0x8000000
> of size 1MB.
>
> Signed-off-by: Eric Auger <[email protected]>
>
> ---
>
> RFC v1 -> v2: use defines for MSI IOVA base and length
> ---
> drivers/iommu/arm-smmu.c | 66
> ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 66 insertions(+)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index c841eb7..c07ea41 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -278,6 +278,9 @@ enum arm_smmu_s2cr_privcfg {
>
> #define FSYNR0_WNR (1 << 4)
>
> +#define MSI_IOVA_BASE 0x8000000
> +#define MSI_IOVA_LENGTH 0x100000
> +
> static int force_stage;
> module_param(force_stage, int, S_IRUGO);
> MODULE_PARM_DESC(force_stage,
> @@ -1533,6 +1536,68 @@ static int arm_smmu_of_xlate(struct device *dev,
> struct of_phandle_args *args)
> return iommu_fwspec_add_ids(dev, &fwid, 1);
> }
>
> +static int add_pci_window_reserved_regions(struct iommu_domain *domain,
> + struct pci_dev *dev)
> +{
> + struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
> + struct iommu_reserved_region *region;
> + struct resource_entry *window;
> + phys_addr_t start;
> + size_t length;
> +
> + resource_list_for_each_entry(window, &bridge->windows) {
> + if (resource_type(window->res) != IORESOURCE_MEM &&
> + resource_type(window->res) != IORESOURCE_IO)
> + continue;
Why do you care about IO resources?
> +
> + start = window->res->start - window->offset;
> + length = window->res->end - window->res->start + 1;
> +
> + iommu_reserved_region_for_each(region, domain) {
> + if (region->start == start && region->length == length)
> + continue;
> + }
> + region = kzalloc(sizeof(*region), GFP_KERNEL);
> + if (!region)
> + return -ENOMEM;
> +
> + region->start = start;
> + region->length = length;
> +
> + list_add_tail(®ion->list, &domain->reserved_regions);
> + }
> + return 0;
> +}
> +
> +static int arm_smmu_add_reserved_regions(struct iommu_domain *domain,
> + struct device *device)
> +{
> + struct iommu_reserved_region *region;
> + int ret = 0;
> +
> + /* An arbitrary 1MB region starting at 0x8000000 is reserved for MSIs */
> + if (!domain->iova_cookie) {
> +
> + region = kzalloc(sizeof(*region), GFP_KERNEL);
> + if (!region)
> + return -ENOMEM;
> +
> + region->start = MSI_IOVA_BASE;
> + region->length = MSI_IOVA_LENGTH;
> + list_add_tail(®ion->list, &domain->reserved_regions);
> +
> + ret = iommu_get_dma_msi_region_cookie(domain,
> + region->start, region->length);
> + if (ret)
> + return ret;
Gah, I hate this. Is there no other and simpler way to get the MSI
region than allocating an iova-domain? In that regard, I also _hate_ the
patch before introducing this weird iommu_get_dma_msi_region_cookie()
function.
Allocation an iova-domain is pretty expensive, as it also includes
per-cpu data-structures and all, so please don't do this just for the
purpose of compiling a list of reserved regions.
Joerg
