xen64: early mapping setup
Set up the initial pagetables to map the kernel mapping into the physical mapping space. This makes __va() usable, since it requires physical mappings. 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
Ingo Molnar
parent
3d75e1b8ef
commit
084a2a4e76
2 changed files with 178 additions and 16 deletions
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@ -33,6 +33,7 @@
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#include <xen/interface/sched.h>
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#include <xen/features.h>
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#include <xen/page.h>
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#include <xen/hvc-console.h>
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#include <asm/paravirt.h>
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#include <asm/page.h>
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@ -1294,6 +1295,157 @@ static void __init xen_reserve_top(void)
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#endif /* CONFIG_X86_32 */
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}
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#ifdef CONFIG_X86_64
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/*
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* Like __va(), but returns address in the kernel mapping (which is
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* all we have until the physical memory mapping has been set up.
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*/
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static void *__ka(phys_addr_t paddr)
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{
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return (void *)(paddr + __START_KERNEL_map);
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}
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/* Convert a machine address to physical address */
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static unsigned long m2p(phys_addr_t maddr)
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{
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phys_addr_t paddr;
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maddr &= PTE_MASK;
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paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
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return paddr;
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}
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/* Convert a machine address to kernel virtual */
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static void *m2v(phys_addr_t maddr)
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{
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return __ka(m2p(maddr));
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}
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static void walk(pgd_t *pgd, unsigned long addr)
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{
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unsigned l4idx = pgd_index(addr);
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unsigned l3idx = pud_index(addr);
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unsigned l2idx = pmd_index(addr);
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unsigned l1idx = pte_index(addr);
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pgd_t l4;
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pud_t l3;
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pmd_t l2;
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pte_t l1;
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xen_raw_printk("walk %p, %lx -> %d %d %d %d\n",
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pgd, addr, l4idx, l3idx, l2idx, l1idx);
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l4 = pgd[l4idx];
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xen_raw_printk(" l4: %016lx\n", l4.pgd);
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xen_raw_printk(" %016lx\n", pgd_val(l4));
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l3 = ((pud_t *)(m2v(l4.pgd)))[l3idx];
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xen_raw_printk(" l3: %016lx\n", l3.pud);
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xen_raw_printk(" %016lx\n", pud_val(l3));
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l2 = ((pmd_t *)(m2v(l3.pud)))[l2idx];
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xen_raw_printk(" l2: %016lx\n", l2.pmd);
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xen_raw_printk(" %016lx\n", pmd_val(l2));
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l1 = ((pte_t *)(m2v(l2.pmd)))[l1idx];
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xen_raw_printk(" l1: %016lx\n", l1.pte);
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xen_raw_printk(" %016lx\n", pte_val(l1));
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}
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static void set_page_prot(void *addr, pgprot_t prot)
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{
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unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
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pte_t pte = pfn_pte(pfn, prot);
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xen_raw_printk("addr=%p pfn=%lx mfn=%lx prot=%016x pte=%016x\n",
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addr, pfn, get_phys_to_machine(pfn),
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pgprot_val(prot), pte.pte);
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if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
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BUG();
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}
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static void convert_pfn_mfn(void *v)
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{
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pte_t *pte = v;
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int i;
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/* All levels are converted the same way, so just treat them
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as ptes. */
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for(i = 0; i < PTRS_PER_PTE; i++)
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pte[i] = xen_make_pte(pte[i].pte);
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}
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/*
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* Set up the inital kernel pagetable.
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*
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* We can construct this by grafting the Xen provided pagetable into
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* head_64.S's preconstructed pagetables. We copy the Xen L2's into
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* level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt. This
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* means that only the kernel has a physical mapping to start with -
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* but that's enough to get __va working. We need to fill in the rest
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* of the physical mapping once some sort of allocator has been set
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* up.
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*/
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static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd)
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{
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pud_t *l3;
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pmd_t *l2;
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/* Zap identity mapping */
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init_level4_pgt[0] = __pgd(0);
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/* Pre-constructed entries are in pfn, so convert to mfn */
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convert_pfn_mfn(init_level4_pgt);
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convert_pfn_mfn(level3_ident_pgt);
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convert_pfn_mfn(level3_kernel_pgt);
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l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
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l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
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memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
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memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
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l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
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l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
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memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
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/* Make pagetable pieces RO */
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set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
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set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
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set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
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set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
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set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
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set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
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/* Pin down new L4 */
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pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(init_level4_pgt)));
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/* Unpin Xen-provided one */
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pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
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/* Switch over */
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pgd = init_level4_pgt;
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xen_write_cr3(__pa(pgd));
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max_pfn_mapped = PFN_DOWN(__pa(pgd) +
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xen_start_info->nr_pt_frames*PAGE_SIZE +
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512*1024);
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return pgd;
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}
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#else
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static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd)
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{
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init_pg_tables_start = __pa(pgd);
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init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
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max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024);
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return pgd;
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}
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#endif /* CONFIG_X86_64 */
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/* First C function to be called on Xen boot */
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asmlinkage void __init xen_start_kernel(void)
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{
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@ -1336,32 +1488,29 @@ asmlinkage void __init xen_start_kernel(void)
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pgd = (pgd_t *)xen_start_info->pt_base;
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#ifdef CONFIG_X86_32
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init_pg_tables_start = __pa(pgd);
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init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
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max_pfn_mapped = (init_pg_tables_end + 512*1024) >> PAGE_SHIFT;
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#endif
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/* Prevent unwanted bits from being set in PTEs. */
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__supported_pte_mask &= ~_PAGE_GLOBAL;
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if (!is_initial_xendomain())
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__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
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init_mm.pgd = pgd; /* use the Xen pagetables to start */
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/* Don't do the full vcpu_info placement stuff until we have a
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possible map and a non-dummy shared_info. */
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per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
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xen_raw_console_write("mapping kernel into physical memory\n");
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pgd = xen_setup_kernel_pagetable(pgd);
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init_mm.pgd = pgd;
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/* keep using Xen gdt for now; no urgent need to change it */
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x86_write_percpu(xen_cr3, __pa(pgd));
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x86_write_percpu(xen_current_cr3, __pa(pgd));
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/* Don't do the full vcpu_info placement stuff until we have a
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possible map and a non-dummy shared_info. */
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per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
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pv_info.kernel_rpl = 1;
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if (xen_feature(XENFEAT_supervisor_mode_kernel))
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pv_info.kernel_rpl = 0;
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/* Prevent unwanted bits from being set in PTEs. */
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__supported_pte_mask &= ~_PAGE_GLOBAL;
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if (!is_initial_xendomain())
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__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
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/* set the limit of our address space */
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xen_reserve_top();
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@ -1384,10 +1533,21 @@ asmlinkage void __init xen_start_kernel(void)
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add_preferred_console("hvc", 0, NULL);
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}
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xen_raw_console_write("about to get started...\n");
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#if 0
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xen_raw_printk("&boot_params=%p __pa(&boot_params)=%lx __va(__pa(&boot_params))=%lx\n",
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&boot_params, __pa_symbol(&boot_params),
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__va(__pa_symbol(&boot_params)));
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walk(pgd, &boot_params);
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walk(pgd, __va(__pa(&boot_params)));
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#endif
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/* Start the world */
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#ifdef CONFIG_X86_32
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i386_start_kernel();
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#else
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x86_64_start_kernel((char *)&boot_params);
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x86_64_start_reservations((char *)__pa_symbol(&boot_params));
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#endif
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}
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@ -16,6 +16,8 @@
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extern pud_t level3_kernel_pgt[512];
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extern pud_t level3_ident_pgt[512];
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extern pmd_t level2_kernel_pgt[512];
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extern pmd_t level2_fixmap_pgt[512];
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extern pmd_t level2_ident_pgt[512];
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extern pgd_t init_level4_pgt[];
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#define swapper_pg_dir init_level4_pgt
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