From d114e1981cc1a51131230993a082c27c79ab370a Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 8 Jul 2008 15:06:52 -0700 Subject: [PATCH] xen64: map an initial chunk of physical memory Early in boot, map a chunk of extra physical memory for use later on. We need a pool of mapped pages to allocate further pages to construct pagetables mapping all physical memory. Signed-off-by: Jeremy Fitzhardinge Cc: Stephen Tweedie Cc: Eduardo Habkost Cc: Mark McLoughlin Signed-off-by: Ingo Molnar --- arch/x86/xen/enlighten.c | 79 +++++++++++++++++++++++++++++++++++----- 1 file changed, 69 insertions(+), 10 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 392450787aa..e9e3bafe48c 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1381,6 +1381,61 @@ static void convert_pfn_mfn(void *v) pte[i] = xen_make_pte(pte[i].pte); } +/* + * Identity map, in addition to plain kernel map. This needs to be + * large enough to allocate page table pages to allocate the rest. + * Each page can map 2MB. + */ +static pte_t level1_ident_pgt[PTRS_PER_PTE * 4] __page_aligned_bss; + +static __init void xen_map_identity_early(unsigned long max_pfn) +{ + unsigned pmdidx, pteidx; + unsigned ident_pte; + unsigned long pfn; + + ident_pte = 0; + pfn = 0; + for(pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) { + pte_t *pte_page; + + BUG_ON(level2_ident_pgt[pmdidx].pmd != level2_kernel_pgt[pmdidx].pmd); + + /* Reuse or allocate a page of ptes */ + if (pmd_present(level2_ident_pgt[pmdidx])) + pte_page = m2v(level2_ident_pgt[pmdidx].pmd); + else { + /* Check for free pte pages */ + if (ident_pte == ARRAY_SIZE(level1_ident_pgt)) + break; + + pte_page = &level1_ident_pgt[ident_pte]; + ident_pte += PTRS_PER_PTE; + + /* Install new l1 in l2(s) */ + level2_ident_pgt[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE); + level2_kernel_pgt[pmdidx] = level2_ident_pgt[pmdidx]; + } + + /* Install mappings */ + for(pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) { + pte_t pte; + + if (pfn > max_pfn_mapped) + max_pfn_mapped = pfn; + + if (!pte_none(pte_page[pteidx])) + continue; + + pte = pfn_pte(pfn, PAGE_KERNEL_EXEC); + pte_page[pteidx] = pte; + } + } + + for(pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE) + set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO); +} + /* * Set up the inital kernel pagetable. * @@ -1392,7 +1447,7 @@ static void convert_pfn_mfn(void *v) * of the physical mapping once some sort of allocator has been set * up. */ -static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd) +static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) { pud_t *l3; pmd_t *l2; @@ -1415,6 +1470,9 @@ static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *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(max_pfn); + /* Make pagetable pieces RO */ set_page_prot(init_level4_pgt, PAGE_KERNEL_RO); set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); @@ -1424,7 +1482,7 @@ static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd) set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); /* Pin down new L4 */ - pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(init_level4_pgt))); + pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa_symbol(init_level4_pgt))); /* Unpin Xen-provided one */ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); @@ -1433,19 +1491,23 @@ static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd) pgd = init_level4_pgt; xen_write_cr3(__pa(pgd)); - max_pfn_mapped = PFN_DOWN(__pa(pgd) + - xen_start_info->nr_pt_frames*PAGE_SIZE + - 512*1024); + reserve_early(__pa(xen_start_info->pt_base), + __pa(xen_start_info->pt_base + + xen_start_info->nr_pt_frames * PAGE_SIZE), + "XEN PAGETABLES"); return pgd; } #else -static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd) +static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) { init_pg_tables_start = __pa(pgd); init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE; max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024); + x86_write_percpu(xen_cr3, __pa(pgd)); + x86_write_percpu(xen_current_cr3, __pa(pgd)); + return pgd; } #endif /* CONFIG_X86_64 */ @@ -1502,15 +1564,12 @@ asmlinkage void __init xen_start_kernel(void) per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; xen_raw_console_write("mapping kernel into physical memory\n"); - pgd = xen_setup_kernel_pagetable(pgd); + pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages); init_mm.pgd = pgd; /* keep using Xen gdt for now; no urgent need to change it */ - x86_write_percpu(xen_cr3, __pa(pgd)); - x86_write_percpu(xen_current_cr3, __pa(pgd)); - pv_info.kernel_rpl = 1; if (xen_feature(XENFEAT_supervisor_mode_kernel)) pv_info.kernel_rpl = 0; -- 2.41.0