From 58a8bb39490db31acbe8f4e24593a88533b4d947 Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Tue, 24 Nov 2020 16:20:57 +0800 Subject: [PATCH] iommu/vt-d: Cleanup after converting to dma-iommu ops Some cleanups after converting the driver to use dma-iommu ops. - Remove nobounce option; - Cleanup and simplify the path in domain mapping. Signed-off-by: Lu Baolu Tested-by: Logan Gunthorpe Link: https://lore.kernel.org/r/20201124082057.2614359-8-baolu.lu@linux.intel.com Signed-off-by: Will Deacon --- Documentation/admin-guide/kernel-parameters.txt | 5 -- drivers/iommu/intel/iommu.c | 90 ++++++++----------------- 2 files changed, 28 insertions(+), 67 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 526d65d..76b2a20 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1883,11 +1883,6 @@ Note that using this option lowers the security provided by tboot because it makes the system vulnerable to DMA attacks. - nobounce [Default off] - Disable bounce buffer for untrusted devices such as - the Thunderbolt devices. This will treat the untrusted - devices as the trusted ones, hence might expose security - risks of DMA attacks. intel_idle.max_cstate= [KNL,HW,ACPI,X86] 0 disables intel_idle and fall back on acpi_idle. diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 30f6909..6d519a6 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -355,7 +355,6 @@ static int dmar_forcedac; static int intel_iommu_strict; static int intel_iommu_superpage = 1; static int iommu_identity_mapping; -static int intel_no_bounce; static int iommu_skip_te_disable; #define IDENTMAP_GFX 2 @@ -457,9 +456,6 @@ static int __init intel_iommu_setup(char *str) } else if (!strncmp(str, "tboot_noforce", 13)) { pr_info("Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n"); intel_iommu_tboot_noforce = 1; - } else if (!strncmp(str, "nobounce", 8)) { - pr_info("Intel-IOMMU: No bounce buffer. This could expose security risks of DMA attacks\n"); - intel_no_bounce = 1; } str += strcspn(str, ","); @@ -2277,15 +2273,14 @@ static inline int hardware_largepage_caps(struct dmar_domain *domain, return level; } -static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, - struct scatterlist *sg, unsigned long phys_pfn, - unsigned long nr_pages, int prot) +static int +__domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, + unsigned long phys_pfn, unsigned long nr_pages, int prot) { struct dma_pte *first_pte = NULL, *pte = NULL; - phys_addr_t pteval; - unsigned long sg_res = 0; unsigned int largepage_lvl = 0; unsigned long lvl_pages = 0; + phys_addr_t pteval; u64 attr; BUG_ON(!domain_pfn_supported(domain, iov_pfn + nr_pages - 1)); @@ -2297,26 +2292,14 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, if (domain_use_first_level(domain)) attr |= DMA_FL_PTE_PRESENT | DMA_FL_PTE_XD | DMA_FL_PTE_US; - if (!sg) { - sg_res = nr_pages; - pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | attr; - } + pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | attr; while (nr_pages > 0) { uint64_t tmp; - if (!sg_res) { - unsigned int pgoff = sg->offset & ~PAGE_MASK; - - sg_res = aligned_nrpages(sg->offset, sg->length); - sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + pgoff; - sg->dma_length = sg->length; - pteval = (sg_phys(sg) - pgoff) | attr; - phys_pfn = pteval >> VTD_PAGE_SHIFT; - } - if (!pte) { - largepage_lvl = hardware_largepage_caps(domain, iov_pfn, phys_pfn, sg_res); + largepage_lvl = hardware_largepage_caps(domain, iov_pfn, + phys_pfn, nr_pages); first_pte = pte = pfn_to_dma_pte(domain, iov_pfn, &largepage_lvl); if (!pte) @@ -2328,7 +2311,7 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, pteval |= DMA_PTE_LARGE_PAGE; lvl_pages = lvl_to_nr_pages(largepage_lvl); - nr_superpages = sg_res / lvl_pages; + nr_superpages = nr_pages / lvl_pages; end_pfn = iov_pfn + nr_superpages * lvl_pages - 1; /* @@ -2362,48 +2345,45 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, lvl_pages = lvl_to_nr_pages(largepage_lvl); BUG_ON(nr_pages < lvl_pages); - BUG_ON(sg_res < lvl_pages); nr_pages -= lvl_pages; iov_pfn += lvl_pages; phys_pfn += lvl_pages; pteval += lvl_pages * VTD_PAGE_SIZE; - sg_res -= lvl_pages; /* If the next PTE would be the first in a new page, then we - need to flush the cache on the entries we've just written. - And then we'll need to recalculate 'pte', so clear it and - let it get set again in the if (!pte) block above. - - If we're done (!nr_pages) we need to flush the cache too. - - Also if we've been setting superpages, we may need to - recalculate 'pte' and switch back to smaller pages for the - end of the mapping, if the trailing size is not enough to - use another superpage (i.e. sg_res < lvl_pages). */ + * need to flush the cache on the entries we've just written. + * And then we'll need to recalculate 'pte', so clear it and + * let it get set again in the if (!pte) block above. + * + * If we're done (!nr_pages) we need to flush the cache too. + * + * Also if we've been setting superpages, we may need to + * recalculate 'pte' and switch back to smaller pages for the + * end of the mapping, if the trailing size is not enough to + * use another superpage (i.e. nr_pages < lvl_pages). + */ pte++; if (!nr_pages || first_pte_in_page(pte) || - (largepage_lvl > 1 && sg_res < lvl_pages)) { + (largepage_lvl > 1 && nr_pages < lvl_pages)) { domain_flush_cache(domain, first_pte, (void *)pte - (void *)first_pte); pte = NULL; } - - if (!sg_res && nr_pages) - sg = sg_next(sg); } + return 0; } -static int domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, - struct scatterlist *sg, unsigned long phys_pfn, - unsigned long nr_pages, int prot) +static int +domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, + unsigned long phys_pfn, unsigned long nr_pages, int prot) { int iommu_id, ret; struct intel_iommu *iommu; /* Do the real mapping first */ - ret = __domain_mapping(domain, iov_pfn, sg, phys_pfn, nr_pages, prot); + ret = __domain_mapping(domain, iov_pfn, phys_pfn, nr_pages, prot); if (ret) return ret; @@ -2415,20 +2395,6 @@ static int domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, return 0; } -static inline int domain_sg_mapping(struct dmar_domain *domain, unsigned long iov_pfn, - struct scatterlist *sg, unsigned long nr_pages, - int prot) -{ - return domain_mapping(domain, iov_pfn, sg, 0, nr_pages, prot); -} - -static inline int domain_pfn_mapping(struct dmar_domain *domain, unsigned long iov_pfn, - unsigned long phys_pfn, unsigned long nr_pages, - int prot) -{ - return domain_mapping(domain, iov_pfn, NULL, phys_pfn, nr_pages, prot); -} - static void domain_context_clear_one(struct intel_iommu *iommu, u8 bus, u8 devfn) { unsigned long flags; @@ -2688,7 +2654,7 @@ static int iommu_domain_identity_map(struct dmar_domain *domain, */ dma_pte_clear_range(domain, first_vpfn, last_vpfn); - return __domain_mapping(domain, first_vpfn, NULL, + return __domain_mapping(domain, first_vpfn, first_vpfn, last_vpfn - first_vpfn + 1, DMA_PTE_READ|DMA_PTE_WRITE); } @@ -4942,8 +4908,8 @@ static int intel_iommu_map(struct iommu_domain *domain, /* Round up size to next multiple of PAGE_SIZE, if it and the low bits of hpa would take us onto the next page */ size = aligned_nrpages(hpa, size); - ret = domain_pfn_mapping(dmar_domain, iova >> VTD_PAGE_SHIFT, - hpa >> VTD_PAGE_SHIFT, size, prot); + ret = domain_mapping(dmar_domain, iova >> VTD_PAGE_SHIFT, + hpa >> VTD_PAGE_SHIFT, size, prot); return ret; } -- 2.7.4