diff options
| -rw-r--r-- | arch/x86/xen/mmu.c | 126 | ||||
| -rw-r--r-- | arch/x86/xen/setup.c | 67 | ||||
| -rw-r--r-- | arch/x86/xen/xen-head.S | 2 |
3 files changed, 156 insertions, 39 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index dd151b2045b0..c04e14e6b301 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1114,6 +1114,77 @@ static void __init xen_cleanhighmap(unsigned long vaddr, xen_mc_flush(); } +/* + * Make a page range writeable and free it. + */ +static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size) +{ + void *vaddr = __va(paddr); + void *vaddr_end = vaddr + size; + + for (; vaddr < vaddr_end; vaddr += PAGE_SIZE) + make_lowmem_page_readwrite(vaddr); + + memblock_free(paddr, size); +} + +static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl) +{ + unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK; + + ClearPagePinned(virt_to_page(__va(pa))); + xen_free_ro_pages(pa, PAGE_SIZE); +} + +/* + * Since it is well isolated we can (and since it is perhaps large we should) + * also free the page tables mapping the initial P->M table. + */ +static void __init xen_cleanmfnmap(unsigned long vaddr) +{ + unsigned long va = vaddr & PMD_MASK; + unsigned long pa; + pgd_t *pgd = pgd_offset_k(va); + pud_t *pud_page = pud_offset(pgd, 0); + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + unsigned int i; + + set_pgd(pgd, __pgd(0)); + do { + pud = pud_page + pud_index(va); + if (pud_none(*pud)) { + va += PUD_SIZE; + } else if (pud_large(*pud)) { + pa = pud_val(*pud) & PHYSICAL_PAGE_MASK; + xen_free_ro_pages(pa, PUD_SIZE); + va += PUD_SIZE; + } else { + pmd = pmd_offset(pud, va); + if (pmd_large(*pmd)) { + pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK; + xen_free_ro_pages(pa, PMD_SIZE); + } else if (!pmd_none(*pmd)) { + pte = pte_offset_kernel(pmd, va); + for (i = 0; i < PTRS_PER_PTE; ++i) { + if (pte_none(pte[i])) + break; + pa = pte_pfn(pte[i]) << PAGE_SHIFT; + xen_free_ro_pages(pa, PAGE_SIZE); + } + xen_cleanmfnmap_free_pgtbl(pte); + } + va += PMD_SIZE; + if (pmd_index(va)) + continue; + xen_cleanmfnmap_free_pgtbl(pmd); + } + + } while (pud_index(va) || pmd_index(va)); + xen_cleanmfnmap_free_pgtbl(pud_page); +} + static void __init xen_pagetable_p2m_free(void) { unsigned long size; @@ -1128,18 +1199,25 @@ static void __init xen_pagetable_p2m_free(void) /* 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. */ + /* + * We could be in __ka space. + * 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); + if (addr >= __START_KERNEL_map) { + xen_cleanhighmap(addr, addr + size); + size = PAGE_ALIGN(xen_start_info->nr_pages * + sizeof(unsigned long)); + memblock_free(__pa(addr), size); + } else { + xen_cleanmfnmap(addr); + } /* 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 @@ -1461,6 +1539,24 @@ static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte) #else /* CONFIG_X86_64 */ static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte) { + unsigned long pfn; + + if (xen_feature(XENFEAT_writable_page_tables) || + xen_feature(XENFEAT_auto_translated_physmap) || + xen_start_info->mfn_list >= __START_KERNEL_map) + return pte; + + /* + * Pages belonging to the initial p2m list mapped outside the default + * address range must be mapped read-only. This region contains the + * page tables for mapping the p2m list, too, and page tables MUST be + * mapped read-only. + */ + pfn = pte_pfn(pte); + if (pfn >= xen_start_info->first_p2m_pfn && + pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames) + pte = __pte_ma(pte_val_ma(pte) & ~_PAGE_RW); + return pte; } #endif /* CONFIG_X86_64 */ @@ -1815,7 +1911,10 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) * mappings. Considering that on Xen after the kernel mappings we * have the mappings of some pages that don't exist in pfn space, we * set max_pfn_mapped to the last real pfn mapped. */ - max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list)); + if (xen_start_info->mfn_list < __START_KERNEL_map) + max_pfn_mapped = xen_start_info->first_p2m_pfn; + else + 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; @@ -1855,6 +1954,11 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) /* Graft it onto L4[511][510] */ copy_page(level2_kernel_pgt, l2); + /* Copy the initial P->M table mappings if necessary. */ + i = pgd_index(xen_start_info->mfn_list); + if (i && i < pgd_index(__START_KERNEL_map)) + init_level4_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i]; + if (!xen_feature(XENFEAT_auto_translated_physmap)) { /* Make pagetable pieces RO */ set_page_prot(init_level4_pgt, PAGE_KERNEL_RO); @@ -1895,6 +1999,8 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) /* Our (by three pages) smaller Xen pagetable that we are using */ memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE); + /* protect xen_start_info */ + memblock_reserve(__pa(xen_start_info), PAGE_SIZE); /* Revector the xen_start_info */ xen_start_info = (struct start_info *)__va(__pa(xen_start_info)); } diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 55f388ef481a..adad417ca1ba 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -560,6 +560,41 @@ static void __init xen_ignore_unusable(struct e820entry *list, size_t map_size) } } +/* + * Reserve Xen mfn_list. + * See comment above "struct start_info" in <xen/interface/xen.h> + * We tried to make the the memblock_reserve more selective so + * that it would be clear what region is reserved. Sadly we ran + * in the problem wherein on a 64-bit hypervisor with a 32-bit + * initial domain, the pt_base has the cr3 value which is not + * neccessarily where the pagetable starts! As Jan put it: " + * Actually, the adjustment turns out to be correct: The page + * tables for a 32-on-64 dom0 get allocated in the order "first L1", + * "first L2", "first L3", so the offset to the page table base is + * indeed 2. When reading xen/include/public/xen.h's comment + * very strictly, this is not a violation (since there nothing is said + * that the first thing in the page table space is pointed to by + * pt_base; I admit that this seems to be implied though, namely + * do I think that it is implied that the page table space is the + * range [pt_base, pt_base + nt_pt_frames), whereas that + * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames), + * which - without a priori knowledge - the kernel would have + * difficulty to figure out)." - so lets just fall back to the + * easy way and reserve the whole region. + */ +static void __init xen_reserve_xen_mfnlist(void) +{ + if (xen_start_info->mfn_list >= __START_KERNEL_map) { + memblock_reserve(__pa(xen_start_info->mfn_list), + xen_start_info->pt_base - + xen_start_info->mfn_list); + return; + } + + memblock_reserve(PFN_PHYS(xen_start_info->first_p2m_pfn), + PFN_PHYS(xen_start_info->nr_p2m_frames)); +} + /** * machine_specific_memory_setup - Hook for machine specific memory setup. **/ @@ -684,35 +719,10 @@ char * __init xen_memory_setup(void) e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, E820_RESERVED); - /* - * Reserve Xen bits: - * - mfn_list - * - xen_start_info - * See comment above "struct start_info" in <xen/interface/xen.h> - * We tried to make the the memblock_reserve more selective so - * that it would be clear what region is reserved. Sadly we ran - * in the problem wherein on a 64-bit hypervisor with a 32-bit - * initial domain, the pt_base has the cr3 value which is not - * neccessarily where the pagetable starts! As Jan put it: " - * Actually, the adjustment turns out to be correct: The page - * tables for a 32-on-64 dom0 get allocated in the order "first L1", - * "first L2", "first L3", so the offset to the page table base is - * indeed 2. When reading xen/include/public/xen.h's comment - * very strictly, this is not a violation (since there nothing is said - * that the first thing in the page table space is pointed to by - * pt_base; I admit that this seems to be implied though, namely - * do I think that it is implied that the page table space is the - * range [pt_base, pt_base + nt_pt_frames), whereas that - * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames), - * which - without a priori knowledge - the kernel would have - * difficulty to figure out)." - so lets just fall back to the - * easy way and reserve the whole region. - */ - memblock_reserve(__pa(xen_start_info->mfn_list), - xen_start_info->pt_base - xen_start_info->mfn_list); - sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); + xen_reserve_xen_mfnlist(); + return "Xen"; } @@ -739,8 +749,7 @@ char * __init xen_auto_xlated_memory_setup(void) for (i = 0; i < memmap.nr_entries; i++) e820_add_region(map[i].addr, map[i].size, map[i].type); - memblock_reserve(__pa(xen_start_info->mfn_list), - xen_start_info->pt_base - xen_start_info->mfn_list); + xen_reserve_xen_mfnlist(); return "Xen"; } diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index 8afdfccf6086..b65f59a358a2 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -104,6 +104,8 @@ ENTRY(hypercall_page) ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, _ASM_PTR __PAGE_OFFSET) #else ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, _ASM_PTR __START_KERNEL_map) + /* Map the p2m table to a 512GB-aligned user address. */ + ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M, .quad PGDIR_SIZE) #endif ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, _ASM_PTR startup_xen) ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page) |
