diff options
Diffstat (limited to 'drivers/iommu/intel-iommu.c')
| -rw-r--r-- | drivers/iommu/intel-iommu.c | 207 |
1 files changed, 205 insertions, 2 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 39b90621a1a1..1eb743c700e9 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -43,6 +43,7 @@ #include <linux/pci-ats.h> #include <linux/memblock.h> #include <linux/dma-contiguous.h> +#include <linux/crash_dump.h> #include <asm/irq_remapping.h> #include <asm/cacheflush.h> #include <asm/iommu.h> @@ -193,7 +194,29 @@ struct root_entry { }; #define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry)) +/* + * Take a root_entry and return the Lower Context Table Pointer (LCTP) + * if marked present. + */ +static phys_addr_t root_entry_lctp(struct root_entry *re) +{ + if (!(re->lo & 1)) + return 0; + + return re->lo & VTD_PAGE_MASK; +} + +/* + * Take a root_entry and return the Upper Context Table Pointer (UCTP) + * if marked present. + */ +static phys_addr_t root_entry_uctp(struct root_entry *re) +{ + if (!(re->hi & 1)) + return 0; + return re->hi & VTD_PAGE_MASK; +} /* * low 64 bits: * 0: present @@ -448,6 +471,11 @@ static bool translation_pre_enabled(struct intel_iommu *iommu) return (iommu->flags & VTD_FLAG_TRANS_PRE_ENABLED); } +static void clear_translation_pre_enabled(struct intel_iommu *iommu) +{ + iommu->flags &= ~VTD_FLAG_TRANS_PRE_ENABLED; +} + static void init_translation_status(struct intel_iommu *iommu) { u32 gsts; @@ -2768,6 +2796,153 @@ static void intel_iommu_init_qi(struct intel_iommu *iommu) } } +static int copy_context_table(struct intel_iommu *iommu, + struct root_entry *old_re, + struct context_entry **tbl, + int bus, bool ext) +{ + struct context_entry *old_ce = NULL, *new_ce = NULL, ce; + int tbl_idx, pos = 0, idx, devfn, ret = 0; + phys_addr_t old_ce_phys; + + tbl_idx = ext ? bus * 2 : bus; + + for (devfn = 0; devfn < 256; devfn++) { + /* First calculate the correct index */ + idx = (ext ? devfn * 2 : devfn) % 256; + + if (idx == 0) { + /* First save what we may have and clean up */ + if (new_ce) { + tbl[tbl_idx] = new_ce; + __iommu_flush_cache(iommu, new_ce, + VTD_PAGE_SIZE); + pos = 1; + } + + if (old_ce) + iounmap(old_ce); + + ret = 0; + if (devfn < 0x80) + old_ce_phys = root_entry_lctp(old_re); + else + old_ce_phys = root_entry_uctp(old_re); + + if (!old_ce_phys) { + if (ext && devfn == 0) { + /* No LCTP, try UCTP */ + devfn = 0x7f; + continue; + } else { + goto out; + } + } + + ret = -ENOMEM; + old_ce = ioremap_cache(old_ce_phys, PAGE_SIZE); + if (!old_ce) + goto out; + + new_ce = alloc_pgtable_page(iommu->node); + if (!new_ce) + goto out_unmap; + + ret = 0; + } + + /* Now copy the context entry */ + ce = old_ce[idx]; + + if (!context_present(&ce)) + continue; + + new_ce[idx] = ce; + } + + tbl[tbl_idx + pos] = new_ce; + + __iommu_flush_cache(iommu, new_ce, VTD_PAGE_SIZE); + +out_unmap: + iounmap(old_ce); + +out: + return ret; +} + +static int copy_translation_tables(struct intel_iommu *iommu) +{ + struct context_entry **ctxt_tbls; + struct root_entry *old_rt; + phys_addr_t old_rt_phys; + int ctxt_table_entries; + unsigned long flags; + u64 rtaddr_reg; + int bus, ret; + bool ext; + + rtaddr_reg = dmar_readq(iommu->reg + DMAR_RTADDR_REG); + ext = !!(rtaddr_reg & DMA_RTADDR_RTT); + + old_rt_phys = rtaddr_reg & VTD_PAGE_MASK; + if (!old_rt_phys) + return -EINVAL; + + old_rt = ioremap_cache(old_rt_phys, PAGE_SIZE); + if (!old_rt) + return -ENOMEM; + + /* This is too big for the stack - allocate it from slab */ + ctxt_table_entries = ext ? 512 : 256; + ret = -ENOMEM; + ctxt_tbls = kzalloc(ctxt_table_entries * sizeof(void *), GFP_KERNEL); + if (!ctxt_tbls) + goto out_unmap; + + for (bus = 0; bus < 256; bus++) { + ret = copy_context_table(iommu, &old_rt[bus], + ctxt_tbls, bus, ext); + if (ret) { + pr_err("%s: Failed to copy context table for bus %d\n", + iommu->name, bus); + continue; + } + } + + spin_lock_irqsave(&iommu->lock, flags); + + /* Context tables are copied, now write them to the root_entry table */ + for (bus = 0; bus < 256; bus++) { + int idx = ext ? bus * 2 : bus; + u64 val; + + if (ctxt_tbls[idx]) { + val = virt_to_phys(ctxt_tbls[idx]) | 1; + iommu->root_entry[bus].lo = val; + } + + if (!ext || !ctxt_tbls[idx + 1]) + continue; + + val = virt_to_phys(ctxt_tbls[idx + 1]) | 1; + iommu->root_entry[bus].hi = val; + } + + spin_unlock_irqrestore(&iommu->lock, flags); + + kfree(ctxt_tbls); + + __iommu_flush_cache(iommu, iommu->root_entry, PAGE_SIZE); + + ret = 0; + +out_unmap: + iounmap(old_rt); + + return ret; +} + static int __init init_dmars(void) { struct dmar_drhd_unit *drhd; @@ -2825,8 +3000,12 @@ static int __init init_dmars(void) init_translation_status(iommu); - if (translation_pre_enabled(iommu)) - pr_info("Translation already enabled - trying to copy translation structures\n"); + if (translation_pre_enabled(iommu) && !is_kdump_kernel()) { + iommu_disable_translation(iommu); + clear_translation_pre_enabled(iommu); + pr_warn("Translation was enabled for %s but we are not in kdump mode\n", + iommu->name); + } /* * TBD: @@ -2837,6 +3016,30 @@ static int __init init_dmars(void) if (ret) goto free_iommu; + if (translation_pre_enabled(iommu)) { + pr_info("Translation already enabled - trying to copy translation structures\n"); + + ret = copy_translation_tables(iommu); + if (ret) { + /* + * We found the IOMMU with translation + * enabled - but failed to copy over the + * old root-entry table. Try to proceed + * by disabling translation now and + * allocating a clean root-entry table. + * This might cause DMAR faults, but + * probably the dump will still succeed. + */ + pr_err("Failed to copy translation tables from previous kernel for %s\n", + iommu->name); + iommu_disable_translation(iommu); + clear_translation_pre_enabled(iommu); + } else { + pr_info("Copied translation tables from previous kernel for %s\n", + iommu->name); + } + } + iommu_flush_write_buffer(iommu); iommu_set_root_entry(iommu); iommu->flush.flush_context(iommu, 0, 0, 0, DMA_CCMD_GLOBAL_INVL); |