diff options
Diffstat (limited to 'arch/x86/kernel/amd_iommu.c')
| -rw-r--r-- | arch/x86/kernel/amd_iommu.c | 231 |
1 files changed, 218 insertions, 13 deletions
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index f2766d84c7a0..c25210e6ac88 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -23,7 +23,7 @@ #include <linux/scatterlist.h> #include <linux/iommu-helper.h> #include <asm/proto.h> -#include <asm/gart.h> +#include <asm/iommu.h> #include <asm/amd_iommu_types.h> #include <asm/amd_iommu.h> @@ -32,21 +32,37 @@ #define to_pages(addr, size) \ (round_up(((addr) & ~PAGE_MASK) + (size), PAGE_SIZE) >> PAGE_SHIFT) +#define EXIT_LOOP_COUNT 10000000 + static DEFINE_RWLOCK(amd_iommu_devtable_lock); -struct command { +/* + * general struct to manage commands send to an IOMMU + */ +struct iommu_cmd { u32 data[4]; }; static int dma_ops_unity_map(struct dma_ops_domain *dma_dom, struct unity_map_entry *e); +/* returns !0 if the IOMMU is caching non-present entries in its TLB */ static int iommu_has_npcache(struct amd_iommu *iommu) { return iommu->cap & IOMMU_CAP_NPCACHE; } -static int __iommu_queue_command(struct amd_iommu *iommu, struct command *cmd) +/**************************************************************************** + * + * IOMMU command queuing functions + * + ****************************************************************************/ + +/* + * Writes the command to the IOMMUs command buffer and informs the + * hardware about the new command. Must be called with iommu->lock held. + */ +static int __iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) { u32 tail, head; u8 *target; @@ -63,7 +79,11 @@ static int __iommu_queue_command(struct amd_iommu *iommu, struct command *cmd) return 0; } -static int iommu_queue_command(struct amd_iommu *iommu, struct command *cmd) +/* + * General queuing function for commands. Takes iommu->lock and calls + * __iommu_queue_command(). + */ +static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) { unsigned long flags; int ret; @@ -75,16 +95,24 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct command *cmd) return ret; } +/* + * This function is called whenever we need to ensure that the IOMMU has + * completed execution of all commands we sent. It sends a + * COMPLETION_WAIT command and waits for it to finish. The IOMMU informs + * us about that by writing a value to a physical address we pass with + * the command. + */ static int iommu_completion_wait(struct amd_iommu *iommu) { int ret; - struct command cmd; + struct iommu_cmd cmd; volatile u64 ready = 0; unsigned long ready_phys = virt_to_phys(&ready); + unsigned long i = 0; memset(&cmd, 0, sizeof(cmd)); cmd.data[0] = LOW_U32(ready_phys) | CMD_COMPL_WAIT_STORE_MASK; - cmd.data[1] = HIGH_U32(ready_phys); + cmd.data[1] = upper_32_bits(ready_phys); cmd.data[2] = 1; /* value written to 'ready' */ CMD_SET_TYPE(&cmd, CMD_COMPL_WAIT); @@ -95,15 +123,23 @@ static int iommu_completion_wait(struct amd_iommu *iommu) if (ret) return ret; - while (!ready) + while (!ready && (i < EXIT_LOOP_COUNT)) { + ++i; cpu_relax(); + } + + if (unlikely((i == EXIT_LOOP_COUNT) && printk_ratelimit())) + printk(KERN_WARNING "AMD IOMMU: Completion wait loop failed\n"); return 0; } +/* + * Command send function for invalidating a device table entry + */ static int iommu_queue_inv_dev_entry(struct amd_iommu *iommu, u16 devid) { - struct command cmd; + struct iommu_cmd cmd; BUG_ON(iommu == NULL); @@ -116,20 +152,23 @@ static int iommu_queue_inv_dev_entry(struct amd_iommu *iommu, u16 devid) return iommu_queue_command(iommu, &cmd); } +/* + * Generic command send function for invalidaing TLB entries + */ static int iommu_queue_inv_iommu_pages(struct amd_iommu *iommu, u64 address, u16 domid, int pde, int s) { - struct command cmd; + struct iommu_cmd cmd; memset(&cmd, 0, sizeof(cmd)); address &= PAGE_MASK; CMD_SET_TYPE(&cmd, CMD_INV_IOMMU_PAGES); cmd.data[1] |= domid; cmd.data[2] = LOW_U32(address); - cmd.data[3] = HIGH_U32(address); - if (s) + cmd.data[3] = upper_32_bits(address); + if (s) /* size bit - we flush more than one 4kb page */ cmd.data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK; - if (pde) + if (pde) /* PDE bit - we wan't flush everything not only the PTEs */ cmd.data[2] |= CMD_INV_IOMMU_PAGES_PDE_MASK; iommu->need_sync = 1; @@ -137,6 +176,11 @@ static int iommu_queue_inv_iommu_pages(struct amd_iommu *iommu, return iommu_queue_command(iommu, &cmd); } +/* + * TLB invalidation function which is called from the mapping functions. + * It invalidates a single PTE if the range to flush is within a single + * page. Otherwise it flushes the whole TLB of the IOMMU. + */ static int iommu_flush_pages(struct amd_iommu *iommu, u16 domid, u64 address, size_t size) { @@ -159,6 +203,20 @@ static int iommu_flush_pages(struct amd_iommu *iommu, u16 domid, return 0; } +/**************************************************************************** + * + * The functions below are used the create the page table mappings for + * unity mapped regions. + * + ****************************************************************************/ + +/* + * Generic mapping functions. It maps a physical address into a DMA + * address space. It allocates the page table pages if necessary. + * In the future it can be extended to a generic mapping function + * supporting all features of AMD IOMMU page tables like level skipping + * and full 64 bit address spaces. + */ static int iommu_map(struct protection_domain *dom, unsigned long bus_addr, unsigned long phys_addr, @@ -209,6 +267,10 @@ static int iommu_map(struct protection_domain *dom, return 0; } +/* + * This function checks if a specific unity mapping entry is needed for + * this specific IOMMU. + */ static int iommu_for_unity_map(struct amd_iommu *iommu, struct unity_map_entry *entry) { @@ -223,6 +285,12 @@ static int iommu_for_unity_map(struct amd_iommu *iommu, return 0; } +/* + * Init the unity mappings for a specific IOMMU in the system + * + * Basically iterates over all unity mapping entries and applies them to + * the default domain DMA of that IOMMU if necessary. + */ static int iommu_init_unity_mappings(struct amd_iommu *iommu) { struct unity_map_entry *entry; @@ -239,6 +307,10 @@ static int iommu_init_unity_mappings(struct amd_iommu *iommu) return 0; } +/* + * This function actually applies the mapping to the page table of the + * dma_ops domain. + */ static int dma_ops_unity_map(struct dma_ops_domain *dma_dom, struct unity_map_entry *e) { @@ -261,6 +333,9 @@ static int dma_ops_unity_map(struct dma_ops_domain *dma_dom, return 0; } +/* + * Inits the unity mappings required for a specific device + */ static int init_unity_mappings_for_device(struct dma_ops_domain *dma_dom, u16 devid) { @@ -278,12 +353,26 @@ static int init_unity_mappings_for_device(struct dma_ops_domain *dma_dom, return 0; } +/**************************************************************************** + * + * The next functions belong to the address allocator for the dma_ops + * interface functions. They work like the allocators in the other IOMMU + * drivers. Its basically a bitmap which marks the allocated pages in + * the aperture. Maybe it could be enhanced in the future to a more + * efficient allocator. + * + ****************************************************************************/ static unsigned long dma_mask_to_pages(unsigned long mask) { return (mask >> PAGE_SHIFT) + (PAGE_ALIGN(mask & ~PAGE_MASK) >> PAGE_SHIFT); } +/* + * The address allocator core function. + * + * called with domain->lock held + */ static unsigned long dma_ops_alloc_addresses(struct device *dev, struct dma_ops_domain *dom, unsigned int pages) @@ -317,6 +406,11 @@ static unsigned long dma_ops_alloc_addresses(struct device *dev, return address; } +/* + * The address free function. + * + * called with domain->lock held + */ static void dma_ops_free_addresses(struct dma_ops_domain *dom, unsigned long address, unsigned int pages) @@ -325,6 +419,16 @@ static void dma_ops_free_addresses(struct dma_ops_domain *dom, iommu_area_free(dom->bitmap, address, pages); } +/**************************************************************************** + * + * The next functions belong to the domain allocation. A domain is + * allocated for every IOMMU as the default domain. If device isolation + * is enabled, every device get its own domain. The most important thing + * about domains is the page table mapping the DMA address space they + * contain. + * + ****************************************************************************/ + static u16 domain_id_alloc(void) { unsigned long flags; @@ -342,6 +446,10 @@ static u16 domain_id_alloc(void) return id; } +/* + * Used to reserve address ranges in the aperture (e.g. for exclusion + * ranges. + */ static void dma_ops_reserve_addresses(struct dma_ops_domain *dom, unsigned long start_page, unsigned int pages) @@ -382,6 +490,10 @@ static void dma_ops_free_pagetable(struct dma_ops_domain *dma_dom) free_page((unsigned long)p1); } +/* + * Free a domain, only used if something went wrong in the + * allocation path and we need to free an already allocated page table + */ static void dma_ops_domain_free(struct dma_ops_domain *dom) { if (!dom) @@ -396,6 +508,11 @@ static void dma_ops_domain_free(struct dma_ops_domain *dom) kfree(dom); } +/* + * Allocates a new protection domain usable for the dma_ops functions. + * It also intializes the page table and the address allocator data + * structures required for the dma_ops interface + */ static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu, unsigned order) { @@ -436,6 +553,7 @@ static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu, dma_dom->bitmap[0] = 1; dma_dom->next_bit = 0; + /* Intialize the exclusion range if necessary */ if (iommu->exclusion_start && iommu->exclusion_start < dma_dom->aperture_size) { unsigned long startpage = iommu->exclusion_start >> PAGE_SHIFT; @@ -444,6 +562,11 @@ static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu, dma_ops_reserve_addresses(dma_dom, startpage, pages); } + /* + * At the last step, build the page tables so we don't need to + * allocate page table pages in the dma_ops mapping/unmapping + * path. + */ num_pte_pages = dma_dom->aperture_size / (PAGE_SIZE * 512); dma_dom->pte_pages = kzalloc(num_pte_pages * sizeof(void *), GFP_KERNEL); @@ -472,6 +595,10 @@ free_dma_dom: return NULL; } +/* + * Find out the protection domain structure for a given PCI device. This + * will give us the pointer to the page table root for example. + */ static struct protection_domain *domain_for_device(u16 devid) { struct protection_domain *dom; @@ -484,6 +611,10 @@ static struct protection_domain *domain_for_device(u16 devid) return dom; } +/* + * If a device is not yet associated with a domain, this function does + * assigns it visible for the hardware + */ static void set_device_domain(struct amd_iommu *iommu, struct protection_domain *domain, u16 devid) @@ -508,6 +639,19 @@ static void set_device_domain(struct amd_iommu *iommu, iommu->need_sync = 1; } +/***************************************************************************** + * + * The next functions belong to the dma_ops mapping/unmapping code. + * + *****************************************************************************/ + +/* + * In the dma_ops path we only have the struct device. This function + * finds the corresponding IOMMU, the protection domain and the + * requestor id for a given device. + * If the device is not yet associated with a domain this is also done + * in this function. + */ static int get_device_resources(struct device *dev, struct amd_iommu **iommu, struct protection_domain **domain, @@ -520,8 +664,9 @@ static int get_device_resources(struct device *dev, BUG_ON(!dev || dev->bus != &pci_bus_type || !dev->dma_mask); pcidev = to_pci_dev(dev); - _bdf = (pcidev->bus->number << 8) | pcidev->devfn; + _bdf = calc_devid(pcidev->bus->number, pcidev->devfn); + /* device not translated by any IOMMU in the system? */ if (_bdf >= amd_iommu_last_bdf) { *iommu = NULL; *domain = NULL; @@ -547,6 +692,10 @@ static int get_device_resources(struct device *dev, return 1; } +/* + * This is the generic map function. It maps one 4kb page at paddr to + * the given address in the DMA address space for the domain. + */ static dma_addr_t dma_ops_domain_map(struct amd_iommu *iommu, struct dma_ops_domain *dom, unsigned long address, @@ -578,6 +727,9 @@ static dma_addr_t dma_ops_domain_map(struct amd_iommu *iommu, return (dma_addr_t)address; } +/* + * The generic unmapping function for on page in the DMA address space. + */ static void dma_ops_domain_unmap(struct amd_iommu *iommu, struct dma_ops_domain *dom, unsigned long address) @@ -597,6 +749,12 @@ static void dma_ops_domain_unmap(struct amd_iommu *iommu, *pte = 0ULL; } +/* + * This function contains common code for mapping of a physically + * contiguous memory region into DMA address space. It is uses by all + * mapping functions provided by this IOMMU driver. + * Must be called with the domain lock held. + */ static dma_addr_t __map_single(struct device *dev, struct amd_iommu *iommu, struct dma_ops_domain *dma_dom, @@ -628,6 +786,10 @@ out: return address; } +/* + * Does the reverse of the __map_single function. Must be called with + * the domain lock held too + */ static void __unmap_single(struct amd_iommu *iommu, struct dma_ops_domain *dma_dom, dma_addr_t dma_addr, @@ -652,6 +814,9 @@ static void __unmap_single(struct amd_iommu *iommu, dma_ops_free_addresses(dma_dom, dma_addr, pages); } +/* + * The exported map_single function for dma_ops. + */ static dma_addr_t map_single(struct device *dev, phys_addr_t paddr, size_t size, int dir) { @@ -664,6 +829,7 @@ static dma_addr_t map_single(struct device *dev, phys_addr_t paddr, get_device_resources(dev, &iommu, &domain, &devid); if (iommu == NULL || domain == NULL) + /* device not handled by any AMD IOMMU */ return (dma_addr_t)paddr; spin_lock_irqsave(&domain->lock, flags); @@ -683,6 +849,9 @@ out: return addr; } +/* + * The exported unmap_single function for dma_ops. + */ static void unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size, int dir) { @@ -692,6 +861,7 @@ static void unmap_single(struct device *dev, dma_addr_t dma_addr, u16 devid; if (!get_device_resources(dev, &iommu, &domain, &devid)) + /* device not handled by any AMD IOMMU */ return; spin_lock_irqsave(&domain->lock, flags); @@ -706,6 +876,10 @@ static void unmap_single(struct device *dev, dma_addr_t dma_addr, spin_unlock_irqrestore(&domain->lock, flags); } +/* + * This is a special map_sg function which is used if we should map a + * device which is not handled by an AMD IOMMU in the system. + */ static int map_sg_no_iommu(struct device *dev, struct scatterlist *sglist, int nelems, int dir) { @@ -720,6 +894,10 @@ static int map_sg_no_iommu(struct device *dev, struct scatterlist *sglist, return nelems; } +/* + * The exported map_sg function for dma_ops (handles scatter-gather + * lists). + */ static int map_sg(struct device *dev, struct scatterlist *sglist, int nelems, int dir) { @@ -775,6 +953,10 @@ unmap: goto out; } +/* + * The exported map_sg function for dma_ops (handles scatter-gather + * lists). + */ static void unmap_sg(struct device *dev, struct scatterlist *sglist, int nelems, int dir) { @@ -804,6 +986,9 @@ static void unmap_sg(struct device *dev, struct scatterlist *sglist, spin_unlock_irqrestore(&domain->lock, flags); } +/* + * The exported alloc_coherent function for dma_ops. + */ static void *alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr, gfp_t flag) { @@ -851,6 +1036,11 @@ out: return virt_addr; } +/* + * The exported free_coherent function for dma_ops. + * FIXME: fix the generic x86 DMA layer so that it actually calls that + * function. + */ static void free_coherent(struct device *dev, size_t size, void *virt_addr, dma_addr_t dma_addr) { @@ -879,6 +1069,8 @@ free_mem: } /* + * The function for pre-allocating protection domains. + * * If the driver core informs the DMA layer if a driver grabs a device * we don't need to preallocate the protection domains anymore. * For now we have to. @@ -921,12 +1113,20 @@ static struct dma_mapping_ops amd_iommu_dma_ops = { .unmap_sg = unmap_sg, }; +/* + * The function which clues the AMD IOMMU driver into dma_ops. + */ int __init amd_iommu_init_dma_ops(void) { struct amd_iommu *iommu; int order = amd_iommu_aperture_order; int ret; + /* + * first allocate a default protection domain for every IOMMU we + * found in the system. Devices not assigned to any other + * protection domain will be assigned to the default one. + */ list_for_each_entry(iommu, &amd_iommu_list, list) { iommu->default_dom = dma_ops_domain_alloc(iommu, order); if (iommu->default_dom == NULL) @@ -936,6 +1136,10 @@ int __init amd_iommu_init_dma_ops(void) goto free_domains; } + /* + * If device isolation is enabled, pre-allocate the protection + * domains for each device. + */ if (amd_iommu_isolate) prealloc_protection_domains(); @@ -947,6 +1151,7 @@ int __init amd_iommu_init_dma_ops(void) gart_iommu_aperture = 0; #endif + /* Make the driver finally visible to the drivers */ dma_ops = &amd_iommu_dma_ops; return 0; |
