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xen32: create initial mappings like 64-bit
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Rearrange the pagetable initialization to share code with the 64-bit
kernel.  Rather than deferring anything to pagetable_setup_start, just
set up an initial pagetable in swapper_pg_dir early at startup, and
create an additional 8MB of physical memory mappings.  This matches
the native head_32.S mappings to a large degree, and allows the rest
of the pagetable setup to continue without much Xen vs. native
difference.

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>
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Jeremy Fitzhardinge authored and Ingo Molnar committed Jul 16, 2008
1 parent d114e19 commit 39dbc5b
Showing 1 changed file with 52 additions and 78 deletions.
130 changes: 52 additions & 78 deletions arch/x86/xen/enlighten.c
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Original file line number Diff line number Diff line change
Expand Up @@ -854,50 +854,6 @@ static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)

static __init void xen_pagetable_setup_start(pgd_t *base)
{
#ifdef CONFIG_X86_32
pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base;
int i;

init_mm.pgd = base;
/*
* copy top-level of Xen-supplied pagetable into place. This
* is a stand-in while we copy the pmd pages.
*/
memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t));

/*
* For PAE, need to allocate new pmds, rather than
* share Xen's, since Xen doesn't like pmd's being
* shared between address spaces.
*/
for (i = 0; i < PTRS_PER_PGD; i++) {
if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) {
pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);

memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]),
PAGE_SIZE);

make_lowmem_page_readonly(pmd);

set_pgd(&base[i], __pgd(1 + __pa(pmd)));
} else
pgd_clear(&base[i]);
}

/* make sure zero_page is mapped RO so we can use it in pagetables */
make_lowmem_page_readonly(empty_zero_page);
make_lowmem_page_readonly(base);
/*
* Switch to new pagetable. This is done before
* pagetable_init has done anything so that the new pages
* added to the table can be prepared properly for Xen.
*/
xen_write_cr3(__pa(base));

/* Unpin initial Xen pagetable */
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
PFN_DOWN(__pa(xen_start_info->pt_base)));
#endif /* CONFIG_X86_32 */
}

void xen_setup_shared_info(void)
Expand Down Expand Up @@ -936,12 +892,6 @@ static __init void xen_pagetable_setup_done(pgd_t *base)
pv_mmu_ops.set_pte = xen_set_pte;

xen_setup_shared_info();

#ifdef CONFIG_X86_32
/* Actually pin the pagetable down, but we can't set PG_pinned
yet because the page structures don't exist yet. */
pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(base)));
#endif
}

static __init void xen_post_allocator_init(void)
Expand Down Expand Up @@ -1299,14 +1249,17 @@ static void __init xen_reserve_top(void)
#endif /* CONFIG_X86_32 */
}

#ifdef CONFIG_X86_64
/*
* Like __va(), but returns address in the kernel mapping (which is
* all we have until the physical memory mapping has been set up.
*/
static void *__ka(phys_addr_t paddr)
{
#ifdef CONFIG_X86_64
return (void *)(paddr + __START_KERNEL_map);
#else
return __va(paddr);
#endif
}

/* Convert a machine address to physical address */
Expand All @@ -1326,6 +1279,7 @@ static void *m2v(phys_addr_t maddr)
return __ka(m2p(maddr));
}

#ifdef CONFIG_X86_64
static void walk(pgd_t *pgd, unsigned long addr)
{
unsigned l4idx = pgd_index(addr);
Expand Down Expand Up @@ -1356,39 +1310,29 @@ static void walk(pgd_t *pgd, unsigned long addr)
xen_raw_printk(" l1: %016lx\n", l1.pte);
xen_raw_printk(" %016lx\n", pte_val(l1));
}
#endif

static void set_page_prot(void *addr, pgprot_t prot)
{
unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
pte_t pte = pfn_pte(pfn, prot);

xen_raw_printk("addr=%p pfn=%lx mfn=%lx prot=%016x pte=%016x\n",
xen_raw_printk("addr=%p pfn=%lx mfn=%lx prot=%016llx pte=%016llx\n",
addr, pfn, get_phys_to_machine(pfn),
pgprot_val(prot), pte.pte);

if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
BUG();
}

static void convert_pfn_mfn(void *v)
{
pte_t *pte = v;
int i;

/* All levels are converted the same way, so just treat them
as ptes. */
for(i = 0; i < PTRS_PER_PTE; i++)
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)
static __init void xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
{
unsigned pmdidx, pteidx;
unsigned ident_pte;
Expand All @@ -1399,11 +1343,9 @@ static __init void xen_map_identity_early(unsigned long max_pfn)
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);
if (pmd_present(pmd[pmdidx]))
pte_page = m2v(pmd[pmdidx].pmd);
else {
/* Check for free pte pages */
if (ident_pte == ARRAY_SIZE(level1_ident_pgt))
Expand All @@ -1412,9 +1354,7 @@ static __init void xen_map_identity_early(unsigned long max_pfn)
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];
pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
}

/* Install mappings */
Expand All @@ -1434,6 +1374,20 @@ static __init void xen_map_identity_early(unsigned long max_pfn)

for(pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);

set_page_prot(pmd, PAGE_KERNEL_RO);
}

#ifdef CONFIG_X86_64
static void convert_pfn_mfn(void *v)
{
pte_t *pte = v;
int i;

/* All levels are converted the same way, so just treat them
as ptes. */
for(i = 0; i < PTRS_PER_PTE; i++)
pte[i] = xen_make_pte(pte[i].pte);
}

/*
Expand Down Expand Up @@ -1471,18 +1425,18 @@ static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pf
memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);

/* Set up identity map */
xen_map_identity_early(max_pfn);
xen_map_identity_early(level2_ident_pgt, max_pfn);

/* 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(level2_ident_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);

/* Pin down new L4 */
pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa_symbol(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)));
Expand All @@ -1498,17 +1452,37 @@ static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pf

return pgd;
}
#else
#else /* !CONFIG_X86_64 */
static pmd_t level2_kernel_pgt[PTRS_PER_PMD] __page_aligned_bss;

static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pmd_t *kernel_pmd;

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));
kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
memcpy(level2_kernel_pgt, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);

return pgd;
xen_map_identity_early(level2_kernel_pgt, max_pfn);

memcpy(swapper_pg_dir, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
set_pgd(&swapper_pg_dir[KERNEL_PGD_BOUNDARY],
__pgd(__pa(level2_kernel_pgt) | _PAGE_PRESENT));

set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
set_page_prot(empty_zero_page, PAGE_KERNEL_RO);

pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));

xen_write_cr3(__pa(swapper_pg_dir));

pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(swapper_pg_dir)));

return swapper_pg_dir;
}
#endif /* CONFIG_X86_64 */

Expand Down

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