xen_mc_flush();
}
+/*
+ * Make a page range writeable and free it.
+ */
+static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
+{
+ void *vaddr = __va(paddr);
+ void *vaddr_end = vaddr + size;
+
+ for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
+ make_lowmem_page_readwrite(vaddr);
+
+ memblock_free(paddr, size);
+}
+
+static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl)
+{
+ unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
+
+ ClearPagePinned(virt_to_page(__va(pa)));
+ xen_free_ro_pages(pa, PAGE_SIZE);
+}
+
+/*
+ * Since it is well isolated we can (and since it is perhaps large we should)
+ * also free the page tables mapping the initial P->M table.
+ */
+static void __init xen_cleanmfnmap(unsigned long vaddr)
+{
+ unsigned long va = vaddr & PMD_MASK;
+ unsigned long pa;
+ pgd_t *pgd = pgd_offset_k(va);
+ pud_t *pud_page = pud_offset(pgd, 0);
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned int i;
+
+ set_pgd(pgd, __pgd(0));
+ do {
+ pud = pud_page + pud_index(va);
+ if (pud_none(*pud)) {
+ va += PUD_SIZE;
+ } else if (pud_large(*pud)) {
+ pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
+ xen_free_ro_pages(pa, PUD_SIZE);
+ va += PUD_SIZE;
+ } else {
+ pmd = pmd_offset(pud, va);
+ if (pmd_large(*pmd)) {
+ pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
+ xen_free_ro_pages(pa, PMD_SIZE);
+ } else if (!pmd_none(*pmd)) {
+ pte = pte_offset_kernel(pmd, va);
+ for (i = 0; i < PTRS_PER_PTE; ++i) {
+ if (pte_none(pte[i]))
+ break;
+ pa = pte_pfn(pte[i]) << PAGE_SHIFT;
+ xen_free_ro_pages(pa, PAGE_SIZE);
+ }
+ xen_cleanmfnmap_free_pgtbl(pte);
+ }
+ va += PMD_SIZE;
+ if (pmd_index(va))
+ continue;
+ xen_cleanmfnmap_free_pgtbl(pmd);
+ }
+
+ } while (pud_index(va) || pmd_index(va));
+ xen_cleanmfnmap_free_pgtbl(pud_page);
+}
+
static void __init xen_pagetable_p2m_free(void)
{
unsigned long size;
/* using __ka address and sticking INVALID_P2M_ENTRY! */
memset((void *)xen_start_info->mfn_list, 0xff, size);
- /* We should be in __ka space. */
- BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
addr = xen_start_info->mfn_list;
- /* We roundup to the PMD, which means that if anybody at this stage is
- * using the __ka address of xen_start_info or xen_start_info->shared_info
- * they are in going to crash. Fortunatly we have already revectored
- * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
+ /*
+ * We could be in __ka space.
+ * We roundup to the PMD, which means that if anybody at this stage is
+ * using the __ka address of xen_start_info or
+ * xen_start_info->shared_info they are in going to crash. Fortunatly
+ * we have already revectored in xen_setup_kernel_pagetable and in
+ * xen_setup_shared_info.
+ */
size = roundup(size, PMD_SIZE);
- xen_cleanhighmap(addr, addr + size);
- size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
- memblock_free(__pa(xen_start_info->mfn_list), size);
+ if (addr >= __START_KERNEL_map) {
+ xen_cleanhighmap(addr, addr + size);
+ size = PAGE_ALIGN(xen_start_info->nr_pages *
+ sizeof(unsigned long));
+ memblock_free(__pa(addr), size);
+ } else {
+ xen_cleanmfnmap(addr);
+ }
/* At this stage, cleanup_highmap has already cleaned __ka space
* from _brk_limit way up to the max_pfn_mapped (which is the end of
#else /* CONFIG_X86_64 */
static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
{
+ unsigned long pfn;
+
+ if (xen_feature(XENFEAT_writable_page_tables) ||
+ xen_feature(XENFEAT_auto_translated_physmap) ||
+ xen_start_info->mfn_list >= __START_KERNEL_map)
+ return pte;
+
+ /*
+ * Pages belonging to the initial p2m list mapped outside the default
+ * address range must be mapped read-only. This region contains the
+ * page tables for mapping the p2m list, too, and page tables MUST be
+ * mapped read-only.
+ */
+ pfn = pte_pfn(pte);
+ if (pfn >= xen_start_info->first_p2m_pfn &&
+ pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
+ pte = __pte_ma(pte_val_ma(pte) & ~_PAGE_RW);
+
return pte;
}
#endif /* CONFIG_X86_64 */
* mappings. Considering that on Xen after the kernel mappings we
* have the mappings of some pages that don't exist in pfn space, we
* set max_pfn_mapped to the last real pfn mapped. */
- max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+ if (xen_start_info->mfn_list < __START_KERNEL_map)
+ max_pfn_mapped = xen_start_info->first_p2m_pfn;
+ else
+ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
pt_end = pt_base + xen_start_info->nr_pt_frames;
/* Graft it onto L4[511][510] */
copy_page(level2_kernel_pgt, l2);
+ /* Copy the initial P->M table mappings if necessary. */
+ i = pgd_index(xen_start_info->mfn_list);
+ if (i && i < pgd_index(__START_KERNEL_map))
+ init_level4_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
+
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
/* Make pagetable pieces RO */
set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
/* Our (by three pages) smaller Xen pagetable that we are using */
memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE);
+ /* protect xen_start_info */
+ memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
/* Revector the xen_start_info */
xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
}
}
}
+/*
+ * Reserve Xen mfn_list.
+ * See comment above "struct start_info" in <xen/interface/xen.h>
+ * We tried to make the the memblock_reserve more selective so
+ * that it would be clear what region is reserved. Sadly we ran
+ * in the problem wherein on a 64-bit hypervisor with a 32-bit
+ * initial domain, the pt_base has the cr3 value which is not
+ * neccessarily where the pagetable starts! As Jan put it: "
+ * Actually, the adjustment turns out to be correct: The page
+ * tables for a 32-on-64 dom0 get allocated in the order "first L1",
+ * "first L2", "first L3", so the offset to the page table base is
+ * indeed 2. When reading xen/include/public/xen.h's comment
+ * very strictly, this is not a violation (since there nothing is said
+ * that the first thing in the page table space is pointed to by
+ * pt_base; I admit that this seems to be implied though, namely
+ * do I think that it is implied that the page table space is the
+ * range [pt_base, pt_base + nt_pt_frames), whereas that
+ * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames),
+ * which - without a priori knowledge - the kernel would have
+ * difficulty to figure out)." - so lets just fall back to the
+ * easy way and reserve the whole region.
+ */
+static void __init xen_reserve_xen_mfnlist(void)
+{
+ if (xen_start_info->mfn_list >= __START_KERNEL_map) {
+ memblock_reserve(__pa(xen_start_info->mfn_list),
+ xen_start_info->pt_base -
+ xen_start_info->mfn_list);
+ return;
+ }
+
+ memblock_reserve(PFN_PHYS(xen_start_info->first_p2m_pfn),
+ PFN_PHYS(xen_start_info->nr_p2m_frames));
+}
+
/**
* machine_specific_memory_setup - Hook for machine specific memory setup.
**/
e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
E820_RESERVED);
- /*
- * Reserve Xen bits:
- * - mfn_list
- * - xen_start_info
- * See comment above "struct start_info" in <xen/interface/xen.h>
- * We tried to make the the memblock_reserve more selective so
- * that it would be clear what region is reserved. Sadly we ran
- * in the problem wherein on a 64-bit hypervisor with a 32-bit
- * initial domain, the pt_base has the cr3 value which is not
- * neccessarily where the pagetable starts! As Jan put it: "
- * Actually, the adjustment turns out to be correct: The page
- * tables for a 32-on-64 dom0 get allocated in the order "first L1",
- * "first L2", "first L3", so the offset to the page table base is
- * indeed 2. When reading xen/include/public/xen.h's comment
- * very strictly, this is not a violation (since there nothing is said
- * that the first thing in the page table space is pointed to by
- * pt_base; I admit that this seems to be implied though, namely
- * do I think that it is implied that the page table space is the
- * range [pt_base, pt_base + nt_pt_frames), whereas that
- * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames),
- * which - without a priori knowledge - the kernel would have
- * difficulty to figure out)." - so lets just fall back to the
- * easy way and reserve the whole region.
- */
- memblock_reserve(__pa(xen_start_info->mfn_list),
- xen_start_info->pt_base - xen_start_info->mfn_list);
-
sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+ xen_reserve_xen_mfnlist();
+
return "Xen";
}
for (i = 0; i < memmap.nr_entries; i++)
e820_add_region(map[i].addr, map[i].size, map[i].type);
- memblock_reserve(__pa(xen_start_info->mfn_list),
- xen_start_info->pt_base - xen_start_info->mfn_list);
+ xen_reserve_xen_mfnlist();
return "Xen";
}
projects / firefly-linux-kernel-4.4.55.git / commitdiff