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SubjectRe: [PATCH v11 08/10] iommu/vt-d: assign new page table for dma_map
On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
> When a device driver issues the first dma_map command for a device, we
> assign a new and empty page-table, thus removing all mappings from the
> old kernel for the device.

Hi Zhenhua,

From your patch I got it will remove all mappings, assign a new
page-table. But I didn't got why you stress an empty page-table. Did I
miss anything?

Thanks
Baoquan

>
> Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
> ---
> drivers/iommu/intel-iommu.c | 58 ++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 50 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 91545bf..3cc1027 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -396,6 +396,9 @@ static int copy_root_entry_table(struct intel_iommu *iommu);
>
> static int intel_iommu_load_translation_tables(struct intel_iommu *iommu);
>
> +static void unmap_device_dma(struct dmar_domain *domain,
> + struct device *dev,
> + struct intel_iommu *iommu);
> static void iommu_check_pre_te_status(struct intel_iommu *iommu);
> static u8 g_translation_pre_enabled;
>
> @@ -3115,6 +3118,7 @@ static struct iova *intel_alloc_iova(struct device *dev,
> static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
> {
> struct dmar_domain *domain;
> + struct intel_iommu *iommu;
> int ret;
>
> domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
> @@ -3124,14 +3128,30 @@ static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
> return NULL;
> }
>
> - /* make sure context mapping is ok */
> - if (unlikely(!domain_context_mapped(dev))) {
> - ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> - if (ret) {
> - printk(KERN_ERR "Domain context map for %s failed",
> - dev_name(dev));
> - return NULL;
> - }
> + /* if in kdump kernel, we need to unmap the mapped dma pages,
> + * detach this device first.
> + */
> + if (likely(domain_context_mapped(dev))) {
> + iommu = domain_get_iommu(domain);
> + if (iommu->pre_enabled_trans) {
> + unmap_device_dma(domain, dev, iommu);
> +
> + domain = get_domain_for_dev(dev,
> + DEFAULT_DOMAIN_ADDRESS_WIDTH);
> + if (!domain) {
> + pr_err("Allocating domain for %s failed",
> + dev_name(dev));
> + return NULL;
> + }
> + } else
> + return domain;
> + }
> +
> + ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> + if (ret) {
> + pr_err("Domain context map for %s failed",
> + dev_name(dev));
> + return NULL;
> }
>
> return domain;
> @@ -5168,6 +5188,28 @@ static int intel_iommu_load_translation_tables(struct intel_iommu *iommu)
> return ret;
> }
>
> +static void unmap_device_dma(struct dmar_domain *domain,
> + struct device *dev,
> + struct intel_iommu *iommu)
> +{
> + struct context_entry *ce;
> + struct iova *iova;
> + phys_addr_t phys_addr;
> + dma_addr_t dev_addr;
> + struct pci_dev *pdev;
> +
> + pdev = to_pci_dev(dev);
> + ce = iommu_context_addr(iommu, pdev->bus->number, pdev->devfn, 1);
> + phys_addr = context_address_root(ce) << VTD_PAGE_SHIFT;
> + dev_addr = phys_to_dma(dev, phys_addr);
> +
> + iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
> + if (iova)
> + intel_unmap(dev, dev_addr);
> +
> + domain_remove_one_dev_info(domain, dev);
> +}
> +
> static void iommu_check_pre_te_status(struct intel_iommu *iommu)
> {
> u32 sts;
> --
> 2.0.0-rc0
>


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