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xen64: map an initial chunk of physical memory

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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 <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jeremy Fitzhardinge 2008-07-08 15:06:52 -07:00 committed by Ingo Molnar
parent 22911b3f1c
commit d114e1981c
1 changed files with 69 additions and 10 deletions
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79
arch/x86/xen/enlighten.c
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@ -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;