diff options
Diffstat (limited to 'arch/x86/xen/mmu.c')
| -rw-r--r-- | arch/x86/xen/mmu.c | 183 |
1 files changed, 148 insertions, 35 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index dfc900471aef..5a16824cc2b3 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -84,6 +84,7 @@ */ DEFINE_SPINLOCK(xen_reservation_lock); +#ifdef CONFIG_X86_32 /* * Identity map, in addition to plain kernel map. This needs to be * large enough to allocate page table pages to allocate the rest. @@ -91,7 +92,7 @@ DEFINE_SPINLOCK(xen_reservation_lock); */ #define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4) static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES); - +#endif #ifdef CONFIG_X86_64 /* l3 pud for userspace vsyscall mapping */ static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss; @@ -1176,13 +1177,6 @@ static void xen_exit_mmap(struct mm_struct *mm) static void xen_post_allocator_init(void); -static void __init xen_pagetable_init(void) -{ - paging_init(); - xen_setup_shared_info(); - xen_post_allocator_init(); -} - static __init void xen_mapping_pagetable_reserve(u64 start, u64 end) { /* reserve the range used */ @@ -1197,6 +1191,87 @@ static __init void xen_mapping_pagetable_reserve(u64 start, u64 end) } } +#ifdef CONFIG_X86_64 +static void __init xen_cleanhighmap(unsigned long vaddr, + unsigned long vaddr_end) +{ + unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1; + pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr); + + /* NOTE: The loop is more greedy than the cleanup_highmap variant. + * We include the PMD passed in on _both_ boundaries. */ + for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE)); + pmd++, vaddr += PMD_SIZE) { + if (pmd_none(*pmd)) + continue; + if (vaddr < (unsigned long) _text || vaddr > kernel_end) + set_pmd(pmd, __pmd(0)); + } + /* In case we did something silly, we should crash in this function + * instead of somewhere later and be confusing. */ + xen_mc_flush(); +} +#endif +static void __init xen_pagetable_init(void) +{ +#ifdef CONFIG_X86_64 + unsigned long size; + unsigned long addr; +#endif + paging_init(); + xen_setup_shared_info(); +#ifdef CONFIG_X86_64 + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned long new_mfn_list; + + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); + + /* On 32-bit, we get zero so this never gets executed. */ + new_mfn_list = xen_revector_p2m_tree(); + if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) { + /* using __ka address and sticking INVALID_P2M_ENTRY! */ + memset((void *)xen_start_info->mfn_list, 0xff, size); + + /* We should be in __ka space. */ + BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map); + addr = xen_start_info->mfn_list; + /* We roundup to the PMD, which means that if anybody at this stage is + * using the __ka address of xen_start_info or xen_start_info->shared_info + * they are in going to crash. Fortunatly we have already revectored + * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */ + size = roundup(size, PMD_SIZE); + xen_cleanhighmap(addr, addr + size); + + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); + memblock_free(__pa(xen_start_info->mfn_list), size); + /* And revector! Bye bye old array */ + xen_start_info->mfn_list = new_mfn_list; + } else + goto skip; + } + /* At this stage, cleanup_highmap has already cleaned __ka space + * from _brk_limit way up to the max_pfn_mapped (which is the end of + * the ramdisk). We continue on, erasing PMD entries that point to page + * tables - do note that they are accessible at this stage via __va. + * For good measure we also round up to the PMD - which means that if + * anybody is using __ka address to the initial boot-stack - and try + * to use it - they are going to crash. The xen_start_info has been + * taken care of already in xen_setup_kernel_pagetable. */ + addr = xen_start_info->pt_base; + size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE); + + xen_cleanhighmap(addr, addr + size); + xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base)); +#ifdef DEBUG + /* This is superflous and is not neccessary, but you know what + * lets do it. The MODULES_VADDR -> MODULES_END should be clear of + * anything at this stage. */ + xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1); +#endif +skip: +#endif + xen_post_allocator_init(); +} static void xen_write_cr2(unsigned long cr2) { this_cpu_read(xen_vcpu)->arch.cr2 = cr2; @@ -1652,7 +1727,7 @@ static void set_page_prot(void *addr, pgprot_t prot) if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0)) BUG(); } - +#ifdef CONFIG_X86_32 static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn) { unsigned pmdidx, pteidx; @@ -1703,7 +1778,7 @@ static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn) set_page_prot(pmd, PAGE_KERNEL_RO); } - +#endif void __init xen_setup_machphys_mapping(void) { struct xen_machphys_mapping mapping; @@ -1731,7 +1806,20 @@ static void convert_pfn_mfn(void *v) for (i = 0; i < PTRS_PER_PTE; i++) pte[i] = xen_make_pte(pte[i].pte); } - +static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end, + unsigned long addr) +{ + if (*pt_base == PFN_DOWN(__pa(addr))) { + set_page_prot((void *)addr, PAGE_KERNEL); + clear_page((void *)addr); + (*pt_base)++; + } + if (*pt_end == PFN_DOWN(__pa(addr))) { + set_page_prot((void *)addr, PAGE_KERNEL); + clear_page((void *)addr); + (*pt_end)--; + } +} /* * Set up the initial kernel pagetable. * @@ -1743,11 +1831,13 @@ static void convert_pfn_mfn(void *v) * of the physical mapping once some sort of allocator has been set * up. */ -pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd, - unsigned long max_pfn) +void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) { pud_t *l3; pmd_t *l2; + unsigned long addr[3]; + unsigned long pt_base, pt_end; + unsigned i; /* max_pfn_mapped is the last pfn mapped in the initial memory * mappings. Considering that on Xen after the kernel mappings we @@ -1755,32 +1845,53 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd, * set max_pfn_mapped to the last real pfn mapped. */ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list)); + pt_base = PFN_DOWN(__pa(xen_start_info->pt_base)); + pt_end = pt_base + xen_start_info->nr_pt_frames; + /* Zap identity mapping */ init_level4_pgt[0] = __pgd(0); /* Pre-constructed entries are in pfn, so convert to mfn */ + /* L4[272] -> level3_ident_pgt + * L4[511] -> level3_kernel_pgt */ convert_pfn_mfn(init_level4_pgt); + + /* L3_i[0] -> level2_ident_pgt */ convert_pfn_mfn(level3_ident_pgt); + /* L3_k[510] -> level2_kernel_pgt + * L3_i[511] -> level2_fixmap_pgt */ convert_pfn_mfn(level3_kernel_pgt); + /* We get [511][511] and have Xen's version of level2_kernel_pgt */ l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd); l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud); - memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD); - memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD); - + addr[0] = (unsigned long)pgd; + addr[1] = (unsigned long)l3; + addr[2] = (unsigned long)l2; + /* Graft it onto L4[272][0]. Note that we creating an aliasing problem: + * Both L4[272][0] and L4[511][511] have entries that point to the same + * L2 (PMD) tables. Meaning that if you modify it in __va space + * it will be also modified in the __ka space! (But if you just + * modify the PMD table to point to other PTE's or none, then you + * are OK - which is what cleanup_highmap does) */ + copy_page(level2_ident_pgt, l2); + /* Graft it onto L4[511][511] */ + copy_page(level2_kernel_pgt, l2); + + /* Get [511][510] and graft that in level2_fixmap_pgt */ l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd); l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud); - memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD); - - /* Set up identity map */ - xen_map_identity_early(level2_ident_pgt, max_pfn); + copy_page(level2_fixmap_pgt, l2); + /* Note that we don't do anything with level1_fixmap_pgt which + * we don't need. */ /* Make pagetable pieces RO */ set_page_prot(init_level4_pgt, PAGE_KERNEL_RO); set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO); set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO); + set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); @@ -1791,22 +1902,28 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd, /* Unpin Xen-provided one */ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); - /* Switch over */ - pgd = init_level4_pgt; - /* * At this stage there can be no user pgd, and no page * structure to attach it to, so make sure we just set kernel * pgd. */ xen_mc_batch(); - __xen_write_cr3(true, __pa(pgd)); + __xen_write_cr3(true, __pa(init_level4_pgt)); xen_mc_issue(PARAVIRT_LAZY_CPU); - memblock_reserve(__pa(xen_start_info->pt_base), - xen_start_info->nr_pt_frames * PAGE_SIZE); + /* We can't that easily rip out L3 and L2, as the Xen pagetables are + * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for + * the initial domain. For guests using the toolstack, they are in: + * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only + * rip out the [L4] (pgd), but for guests we shave off three pages. + */ + for (i = 0; i < ARRAY_SIZE(addr); i++) + check_pt_base(&pt_base, &pt_end, addr[i]); - return pgd; + /* Our (by three pages) smaller Xen pagetable that we are using */ + memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE); + /* Revector the xen_start_info */ + xen_start_info = (struct start_info *)__va(__pa(xen_start_info)); } #else /* !CONFIG_X86_64 */ static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD); @@ -1831,8 +1948,7 @@ static void __init xen_write_cr3_init(unsigned long cr3) */ swapper_kernel_pmd = extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); - memcpy(swapper_kernel_pmd, initial_kernel_pmd, - sizeof(pmd_t) * PTRS_PER_PMD); + copy_page(swapper_kernel_pmd, initial_kernel_pmd); swapper_pg_dir[KERNEL_PGD_BOUNDARY] = __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT); set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO); @@ -1849,8 +1965,7 @@ static void __init xen_write_cr3_init(unsigned long cr3) pv_mmu_ops.write_cr3 = &xen_write_cr3; } -pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd, - unsigned long max_pfn) +void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) { pmd_t *kernel_pmd; @@ -1862,11 +1977,11 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd, 512*1024); kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd); - memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD); + copy_page(initial_kernel_pmd, kernel_pmd); xen_map_identity_early(initial_kernel_pmd, max_pfn); - memcpy(initial_page_table, pgd, sizeof(pgd_t) * PTRS_PER_PGD); + copy_page(initial_page_table, pgd); initial_page_table[KERNEL_PGD_BOUNDARY] = __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT); @@ -1882,8 +1997,6 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd, memblock_reserve(__pa(xen_start_info->pt_base), xen_start_info->nr_pt_frames * PAGE_SIZE); - - return initial_page_table; } #endif /* CONFIG_X86_64 */ |