--- /dev/null
+From: jbeulich@novell.com
+Subject: eliminate scalability issues from initial mapping setup
+Patch-mainline: obsolete
+References: bnc#417417
+
+Direct Xen to place the initial P->M table outside of the initial
+mapping, as otherwise the 1G (implementation) / 2G (theoretical)
+restriction on the size of the initial mapping limits the amount
+of memory a domain can be handed initially.
+
+Note that the flags passed to HYPERVISOR_update_va_mapping() from
+__make_page_writable() and make_lowmem_page_writable() are
+intentionally not including UVMF_ALL. This is intended to be on optimal
+choice between the overhead of a potential spurious page fault (as
+remote CPUs may still have read-only translations in their TLBs) and
+the overhead of cross processor flushes. Flushing on the local CPU
+shouldn't be as expensive (and hence can be viewed as an optimization
+avoiding the spurious page fault on the local CPU), but is required
+when the functions are used before the page fault handler gets set up.
+
+--- sle11-2009-05-14.orig/arch/x86/kernel/head64-xen.c 2009-02-16 16:49:32.000000000 +0100
++++ sle11-2009-05-14/arch/x86/kernel/head64-xen.c 2009-03-16 16:40:54.000000000 +0100
+@@ -171,6 +171,14 @@ void __init x86_64_start_reservations(ch
+ + (xen_start_info->nr_pt_frames << PAGE_SHIFT),
+ "Xen provided");
+
++ if (xen_feature(XENFEAT_auto_translated_physmap))
++ xen_start_info->mfn_list = ~0UL;
++ else if (xen_start_info->mfn_list < __START_KERNEL_map)
++ reserve_early(xen_start_info->first_p2m_pfn << PAGE_SHIFT,
++ (xen_start_info->first_p2m_pfn
++ + xen_start_info->nr_p2m_frames) << PAGE_SHIFT,
++ "INITP2M");
++
+ /*
+ * At this point everything still needed from the boot loader
+ * or BIOS or kernel text should be early reserved or marked not
+--- sle11-2009-05-14.orig/arch/x86/kernel/head_64-xen.S 2009-03-16 16:40:52.000000000 +0100
++++ sle11-2009-05-14/arch/x86/kernel/head_64-xen.S 2009-03-16 16:40:54.000000000 +0100
+@@ -18,6 +18,7 @@
+ #include <asm/desc.h>
+ #include <asm/segment.h>
+ #include <asm/page.h>
++#include <asm/pgtable.h>
+ #include <asm/msr.h>
+ #include <asm/cache.h>
+ #include <asm/dwarf2.h>
+@@ -135,6 +136,7 @@ ENTRY(empty_zero_page)
+ ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, .quad startup_64)
+ ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .quad hypercall_page)
+ ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID, .quad _PAGE_PRESENT, _PAGE_PRESENT)
++ ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M, .quad VMEMMAP_START)
+ ELFNOTE(Xen, XEN_ELFNOTE_FEATURES, .asciz "writable_page_tables|writable_descriptor_tables|auto_translated_physmap|pae_pgdir_above_4gb|supervisor_mode_kernel")
+ ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
+ ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
+--- sle11-2009-05-14.orig/arch/x86/kernel/setup-xen.c 2009-02-16 17:05:16.000000000 +0100
++++ sle11-2009-05-14/arch/x86/kernel/setup-xen.c 2009-03-16 16:40:54.000000000 +0100
+@@ -1022,7 +1022,7 @@ void __init setup_arch(char **cmdline_p)
+ difference = xen_start_info->nr_pages - max_pfn;
+
+ set_xen_guest_handle(reservation.extent_start,
+- ((unsigned long *)xen_start_info->mfn_list) + max_pfn);
++ phys_to_machine_mapping + max_pfn);
+ reservation.nr_extents = difference;
+ ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
+ &reservation);
+@@ -1039,14 +1039,86 @@ void __init setup_arch(char **cmdline_p)
+ phys_to_machine_mapping = alloc_bootmem_pages(
+ max_pfn * sizeof(unsigned long));
+ memcpy(phys_to_machine_mapping,
+- (unsigned long *)xen_start_info->mfn_list,
++ __va(__pa(xen_start_info->mfn_list)),
+ p2m_pages * sizeof(unsigned long));
+ memset(phys_to_machine_mapping + p2m_pages, ~0,
+ (max_pfn - p2m_pages) * sizeof(unsigned long));
+- free_bootmem(
+- __pa(xen_start_info->mfn_list),
+- PFN_PHYS(PFN_UP(xen_start_info->nr_pages *
+- sizeof(unsigned long))));
++
++#ifdef CONFIG_X86_64
++ if (xen_start_info->mfn_list == VMEMMAP_START) {
++ /*
++ * 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.
++ */
++ unsigned long va = VMEMMAP_START, pa;
++ pgd_t *pgd = pgd_offset_k(va);
++ pud_t *pud_page = pud_offset(pgd, 0);
++
++ BUILD_BUG_ON(VMEMMAP_START & ~PGDIR_MASK);
++ xen_l4_entry_update(pgd, __pgd(0));
++ for(;;) {
++ pud_t *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;
++ make_pages_writable(__va(pa),
++ PUD_SIZE >> PAGE_SHIFT,
++ XENFEAT_writable_page_tables);
++ free_bootmem(pa, PUD_SIZE);
++ va += PUD_SIZE;
++ } else {
++ pmd_t *pmd = pmd_offset(pud, va);
++
++ if (pmd_large(*pmd)) {
++ pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
++ make_pages_writable(__va(pa),
++ PMD_SIZE >> PAGE_SHIFT,
++ XENFEAT_writable_page_tables);
++ free_bootmem(pa, PMD_SIZE);
++ } else if (!pmd_none(*pmd)) {
++ pte_t *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;
++ make_page_writable(__va(pa),
++ XENFEAT_writable_page_tables);
++ free_bootmem(pa, PAGE_SIZE);
++ }
++ ClearPagePinned(virt_to_page(pte));
++ make_page_writable(pte,
++ XENFEAT_writable_page_tables);
++ free_bootmem(__pa(pte), PAGE_SIZE);
++ }
++ va += PMD_SIZE;
++ if (pmd_index(va))
++ continue;
++ ClearPagePinned(virt_to_page(pmd));
++ make_page_writable(pmd,
++ XENFEAT_writable_page_tables);
++ free_bootmem(__pa((unsigned long)pmd
++ & PAGE_MASK),
++ PAGE_SIZE);
++ }
++ if (!pud_index(va))
++ break;
++ }
++ ClearPagePinned(virt_to_page(pud_page));
++ make_page_writable(pud_page,
++ XENFEAT_writable_page_tables);
++ free_bootmem(__pa((unsigned long)pud_page & PAGE_MASK),
++ PAGE_SIZE);
++ } else if (!WARN_ON(xen_start_info->mfn_list
++ < __START_KERNEL_map))
++#endif
++ free_bootmem(__pa(xen_start_info->mfn_list),
++ PFN_PHYS(PFN_UP(xen_start_info->nr_pages *
++ sizeof(unsigned long))));
++
+
+ /*
+ * Initialise the list of the frames that specify the list of
+--- sle11-2009-05-14.orig/arch/x86/mm/init_64-xen.c 2009-03-16 16:40:52.000000000 +0100
++++ sle11-2009-05-14/arch/x86/mm/init_64-xen.c 2009-03-16 16:40:54.000000000 +0100
+@@ -157,6 +157,17 @@ static unsigned long __meminitdata table
+ static unsigned long __meminitdata table_cur;
+ static unsigned long __meminitdata table_top;
+
++static __init unsigned long get_table_cur(void)
++{
++ BUG_ON(!table_cur);
++ if (xen_start_info->mfn_list < __START_KERNEL_map
++ && table_cur == xen_start_info->first_p2m_pfn) {
++ table_cur += xen_start_info->nr_p2m_frames;
++ table_top += xen_start_info->nr_p2m_frames;
++ }
++ return table_cur++;
++}
++
+ /*
+ * NOTE: This function is marked __ref because it calls __init function
+ * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
+@@ -168,8 +179,7 @@ static __ref void *spp_getpage(void)
+ if (after_bootmem)
+ ptr = (void *) get_zeroed_page(GFP_ATOMIC);
+ else if (table_cur < table_top) {
+- ptr = __va(table_cur << PAGE_SHIFT);
+- table_cur++;
++ ptr = __va(get_table_cur() << PAGE_SHIFT);
+ memset(ptr, 0, PAGE_SIZE);
+ } else
+ ptr = alloc_bootmem_pages(PAGE_SIZE);
+@@ -334,8 +344,7 @@ static __ref void *alloc_low_page(unsign
+ return adr;
+ }
+
+- BUG_ON(!table_cur);
+- pfn = table_cur++;
++ pfn = get_table_cur();
+ if (pfn >= table_top)
+ panic("alloc_low_page: ran out of memory");
+
+@@ -361,14 +370,29 @@ static inline int __meminit make_readonl
+ /* Make new page tables read-only on the first pass. */
+ if (!xen_feature(XENFEAT_writable_page_tables)
+ && !max_pfn_mapped
+- && (paddr >= (table_start << PAGE_SHIFT))
+- && (paddr < (table_top << PAGE_SHIFT)))
+- readonly = 1;
++ && (paddr >= (table_start << PAGE_SHIFT))) {
++ unsigned long top = table_top;
++
++ /* Account for the range get_table_cur() skips. */
++ if (xen_start_info->mfn_list < __START_KERNEL_map
++ && table_cur <= xen_start_info->first_p2m_pfn
++ && top > xen_start_info->first_p2m_pfn)
++ top += xen_start_info->nr_p2m_frames;
++ if (paddr < (top << PAGE_SHIFT))
++ readonly = 1;
++ }
+ /* Make old page tables read-only. */
+ if (!xen_feature(XENFEAT_writable_page_tables)
+ && (paddr >= (xen_start_info->pt_base - __START_KERNEL_map))
+ && (paddr < (table_cur << PAGE_SHIFT)))
+ readonly = 1;
++ /* Make P->M table (and its page tables) read-only. */
++ if (!xen_feature(XENFEAT_writable_page_tables)
++ && xen_start_info->mfn_list < __START_KERNEL_map
++ && paddr >= (xen_start_info->first_p2m_pfn << PAGE_SHIFT)
++ && paddr < (xen_start_info->first_p2m_pfn
++ + xen_start_info->nr_p2m_frames) << PAGE_SHIFT)
++ readonly = 1;
+
+ /*
+ * No need for writable mapping of kernel image. This also ensures that
+@@ -616,6 +640,12 @@ void __init xen_init_pt(void)
+ __pud(__pa_symbol(level2_kernel_pgt) | _PAGE_TABLE);
+ memcpy(level2_kernel_pgt, page, PAGE_SIZE);
+
++ /* Copy the initial P->M table mappings if necessary. */
++ addr = pgd_index(xen_start_info->mfn_list);
++ if (addr < pgd_index(__START_KERNEL_map))
++ init_level4_pgt[addr] =
++ ((pgd_t *)xen_start_info->pt_base)[addr];
++
+ /* Do an early initialization of the fixmap area. */
+ addr = __fix_to_virt(FIX_EARLYCON_MEM_BASE);
+ level3_kernel_pgt[pud_index(addr)] =
+@@ -676,22 +706,28 @@ static void __init find_early_table_spac
+ static void __init xen_finish_init_mapping(void)
+ {
+ unsigned long i, start, end;
++ struct mmuext_op mmuext;
+
+ /* Re-vector virtual addresses pointing into the initial
+ mapping to the just-established permanent ones. */
+ xen_start_info = __va(__pa(xen_start_info));
+ xen_start_info->pt_base = (unsigned long)
+ __va(__pa(xen_start_info->pt_base));
+- if (!xen_feature(XENFEAT_auto_translated_physmap)) {
++ if (!xen_feature(XENFEAT_auto_translated_physmap)
++ && xen_start_info->mfn_list >= __START_KERNEL_map)
+ phys_to_machine_mapping =
+ __va(__pa(xen_start_info->mfn_list));
+- xen_start_info->mfn_list = (unsigned long)
+- phys_to_machine_mapping;
+- }
+ if (xen_start_info->mod_start)
+ xen_start_info->mod_start = (unsigned long)
+ __va(__pa(xen_start_info->mod_start));
+
++ /* Unpin the no longer used Xen provided page tables. */
++ mmuext.cmd = MMUEXT_UNPIN_TABLE;
++ mmuext.arg1.mfn = pfn_to_mfn(__pa(xen_start_info->pt_base)
++ >> PAGE_SHIFT);
++ if (HYPERVISOR_mmuext_op(&mmuext, 1, NULL, DOMID_SELF))
++ BUG();
++
+ /* Destroy the Xen-created mappings beyond the kernel image. */
+ start = PAGE_ALIGN((unsigned long)_end);
+ end = __START_KERNEL_map + (table_start << PAGE_SHIFT);
+@@ -948,9 +984,20 @@ unsigned long __init_refok init_memory_m
+
+ __flush_tlb_all();
+
+- if (!after_bootmem && table_top > table_start)
++ if (!after_bootmem && table_top > table_start) {
++ if (xen_start_info->mfn_list < __START_KERNEL_map
++ && table_start <= xen_start_info->first_p2m_pfn
++ && table_top > xen_start_info->first_p2m_pfn) {
++ reserve_early(table_start << PAGE_SHIFT,
++ xen_start_info->first_p2m_pfn
++ << PAGE_SHIFT,
++ "PGTABLE");
++ table_start = xen_start_info->first_p2m_pfn
++ + xen_start_info->nr_p2m_frames;
++ }
+ reserve_early(table_start << PAGE_SHIFT,
+ table_top << PAGE_SHIFT, "PGTABLE");
++ }
+
+ printk(KERN_INFO "last_map_addr: %lx end: %lx\n",
+ last_map_addr, end);
+--- sle11-2009-05-14.orig/arch/x86/mm/pageattr-xen.c 2009-03-16 16:40:01.000000000 +0100
++++ sle11-2009-05-14/arch/x86/mm/pageattr-xen.c 2009-03-16 16:40:54.000000000 +0100
+@@ -1251,7 +1251,7 @@ static void __make_page_writable(unsigne
+
+ pte = lookup_address(va, &level);
+ BUG_ON(!pte || level != PG_LEVEL_4K);
+- if (HYPERVISOR_update_va_mapping(va, pte_mkwrite(*pte), 0))
++ if (HYPERVISOR_update_va_mapping(va, pte_mkwrite(*pte), UVMF_INVLPG))
+ BUG();
+ if (in_secondary_range(va)) {
+ unsigned long pfn = pte_pfn(*pte);
+--- sle11-2009-05-14.orig/arch/x86/mm/pgtable-xen.c 2009-04-09 14:54:18.000000000 +0200
++++ sle11-2009-05-14/arch/x86/mm/pgtable-xen.c 2009-03-16 16:40:54.000000000 +0100
+@@ -323,7 +323,7 @@ void __init xen_init_pgd_pin(void)
+ if (PTRS_PER_PUD > 1) /* not folded */
+ SetPagePinned(virt_to_page(pud));
+ for (u = 0; u < PTRS_PER_PUD; u++, pud++) {
+- if (!pud_present(*pud))
++ if (!pud_present(*pud) || pud_large(*pud))
+ continue;
+ pmd = pmd_offset(pud, 0);
+ if (PTRS_PER_PMD > 1) /* not folded */
+@@ -334,7 +334,7 @@ void __init xen_init_pgd_pin(void)
+ && m >= pmd_index(HYPERVISOR_VIRT_START))
+ continue;
+ #endif
+- if (!pmd_present(*pmd))
++ if (!pmd_present(*pmd) || pmd_large(*pmd))
+ continue;
+ SetPagePinned(pmd_page(*pmd));
+ }
+--- sle11-2009-05-14.orig/arch/x86/mm/pgtable_32-xen.c 2009-03-16 16:38:16.000000000 +0100
++++ sle11-2009-05-14/arch/x86/mm/pgtable_32-xen.c 2009-03-16 16:40:54.000000000 +0100
+@@ -188,6 +188,6 @@ void make_lowmem_page_writable(void *va,
+ pte = lookup_address((unsigned long)va, &level);
+ BUG_ON(!pte || level != PG_LEVEL_4K || !pte_present(*pte));
+ rc = HYPERVISOR_update_va_mapping(
+- (unsigned long)va, pte_mkwrite(*pte), 0);
++ (unsigned long)va, pte_mkwrite(*pte), UVMF_INVLPG);
+ BUG_ON(rc);
+ }
+--- sle11-2009-05-14.orig/include/xen/interface/elfnote.h 2008-11-25 12:35:56.000000000 +0100
++++ sle11-2009-05-14/include/xen/interface/elfnote.h 2009-03-16 16:40:54.000000000 +0100
+@@ -162,9 +162,20 @@
+ #define XEN_ELFNOTE_SUSPEND_CANCEL 14
+
+ /*
++ * The (non-default) location the initial phys-to-machine map should be
++ * placed at by the hypervisor (Dom0) or the tools (DomU).
++ * The kernel must be prepared for this mapping to be established using
++ * large pages, despite such otherwise not being available to guests.
++ * The kernel must also be prepared that the page table pages used for
++ * this mapping may not be accessible through the initial mapping.
++ * (Only x86-64 supports this at present.)
++ */
++#define XEN_ELFNOTE_INIT_P2M 15
++
++/*
+ * The number of the highest elfnote defined.
+ */
+-#define XEN_ELFNOTE_MAX XEN_ELFNOTE_SUSPEND_CANCEL
++#define XEN_ELFNOTE_MAX XEN_ELFNOTE_INIT_P2M
+
+ /*
+ * System information exported through crash notes.
+--- sle11-2009-05-14.orig/include/xen/interface/xen.h 2009-05-14 11:17:48.000000000 +0200
++++ sle11-2009-05-14/include/xen/interface/xen.h 2009-03-16 16:40:54.000000000 +0100
+@@ -536,6 +536,7 @@ typedef struct shared_info shared_info_t
+ * a. relocated kernel image
+ * b. initial ram disk [mod_start, mod_len]
+ * c. list of allocated page frames [mfn_list, nr_pages]
++ * (unless relocated due to XEN_ELFNOTE_INIT_P2M)
+ * d. start_info_t structure [register ESI (x86)]
+ * e. bootstrap page tables [pt_base, CR3 (x86)]
+ * f. bootstrap stack [register ESP (x86)]
+@@ -577,6 +578,9 @@ struct start_info {
+ unsigned long mod_start; /* VIRTUAL address of pre-loaded module. */
+ unsigned long mod_len; /* Size (bytes) of pre-loaded module. */
+ int8_t cmd_line[MAX_GUEST_CMDLINE];
++ /* The pfn range here covers both page table and p->m table frames. */
++ unsigned long first_p2m_pfn;/* 1st pfn forming initial P->M table. */
++ unsigned long nr_p2m_frames;/* # of pfns forming initial P->M table. */
+ };
+ typedef struct start_info start_info_t;
+
projects / people / pmueller / ipfire-2.x.git / blobdiff