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Commit d114e198 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
Browse files

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: default avatarJeremy 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: default avatarIngo Molnar <mingo@elte.hu>
parent 22911b3f

arch/x86/xen/enlighten.c

+69 −10
Original line number Diff line number Diff line
@@ -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;