diff options
| -rw-r--r-- | arch/x86/xen/p2m.c | 23 | ||||
| -rw-r--r-- | arch/x86/xen/p2m.h | 15 | ||||
| -rw-r--r-- | arch/x86/xen/setup.c | 370 |
3 files changed, 314 insertions, 94 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 3172692381ae..9f5983b01ed9 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -173,6 +173,7 @@ #include <xen/balloon.h> #include <xen/grant_table.h> +#include "p2m.h" #include "multicalls.h" #include "xen-ops.h" @@ -180,12 +181,6 @@ static void __init m2p_override_init(void); unsigned long xen_max_p2m_pfn __read_mostly; -#define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long)) -#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) -#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) - -#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) - /* Placeholders for holes in the address space */ static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE); static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE); @@ -202,16 +197,12 @@ static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_identity_mfn, P2M_MID_PER_PAGE); RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); -/* We might hit two boundary violations at the start and end, at max each - * boundary violation will require three middle nodes. */ -RESERVE_BRK(p2m_mid_extra, PAGE_SIZE * 2 * 3); - -/* When we populate back during bootup, the amount of pages can vary. The - * max we have is seen is 395979, but that does not mean it can't be more. - * Some machines can have 3GB I/O holes even. With early_can_reuse_p2m_middle - * it can re-use Xen provided mfn_list array, so we only need to allocate at - * most three P2M top nodes. */ -RESERVE_BRK(p2m_populated, PAGE_SIZE * 3); +/* For each I/O range remapped we may lose up to two leaf pages for the boundary + * violations and three mid pages to cover up to 3GB. With + * early_can_reuse_p2m_middle() most of the leaf pages will be reused by the + * remapped region. + */ +RESERVE_BRK(p2m_identity_remap, PAGE_SIZE * 2 * 3 * MAX_REMAP_RANGES); static inline unsigned p2m_top_index(unsigned long pfn) { diff --git a/arch/x86/xen/p2m.h b/arch/x86/xen/p2m.h new file mode 100644 index 000000000000..ad8aee24ab72 --- /dev/null +++ b/arch/x86/xen/p2m.h @@ -0,0 +1,15 @@ +#ifndef _XEN_P2M_H +#define _XEN_P2M_H + +#define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long)) +#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) +#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) + +#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) + +#define MAX_REMAP_RANGES 10 + +extern unsigned long __init set_phys_range_identity(unsigned long pfn_s, + unsigned long pfn_e); + +#endif /* _XEN_P2M_H */ diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 2e555163c2fe..af7216128d93 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -29,6 +29,7 @@ #include <xen/features.h> #include "xen-ops.h" #include "vdso.h" +#include "p2m.h" /* These are code, but not functions. Defined in entry.S */ extern const char xen_hypervisor_callback[]; @@ -46,6 +47,9 @@ struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; /* Number of pages released from the initial allocation. */ unsigned long xen_released_pages; +/* Buffer used to remap identity mapped pages */ +unsigned long xen_remap_buf[P2M_PER_PAGE] __initdata; + /* * The maximum amount of extra memory compared to the base size. The * main scaling factor is the size of struct page. At extreme ratios @@ -151,107 +155,325 @@ static unsigned long __init xen_do_chunk(unsigned long start, return len; } -static unsigned long __init xen_release_chunk(unsigned long start, - unsigned long end) -{ - return xen_do_chunk(start, end, true); -} - -static unsigned long __init xen_populate_chunk( +/* + * Finds the next RAM pfn available in the E820 map after min_pfn. + * This function updates min_pfn with the pfn found and returns + * the size of that range or zero if not found. + */ +static unsigned long __init xen_find_pfn_range( const struct e820entry *list, size_t map_size, - unsigned long max_pfn, unsigned long *last_pfn, - unsigned long credits_left) + unsigned long *min_pfn) { const struct e820entry *entry; unsigned int i; unsigned long done = 0; - unsigned long dest_pfn; for (i = 0, entry = list; i < map_size; i++, entry++) { unsigned long s_pfn; unsigned long e_pfn; - unsigned long pfns; - long capacity; - - if (credits_left <= 0) - break; if (entry->type != E820_RAM) continue; e_pfn = PFN_DOWN(entry->addr + entry->size); - /* We only care about E820 after the xen_start_info->nr_pages */ - if (e_pfn <= max_pfn) + /* We only care about E820 after this */ + if (e_pfn < *min_pfn) continue; s_pfn = PFN_UP(entry->addr); - /* If the E820 falls within the nr_pages, we want to start - * at the nr_pages PFN. - * If that would mean going past the E820 entry, skip it + + /* If min_pfn falls within the E820 entry, we want to start + * at the min_pfn PFN. */ - if (s_pfn <= max_pfn) { - capacity = e_pfn - max_pfn; - dest_pfn = max_pfn; + if (s_pfn <= *min_pfn) { + done = e_pfn - *min_pfn; } else { - capacity = e_pfn - s_pfn; - dest_pfn = s_pfn; + done = e_pfn - s_pfn; + *min_pfn = s_pfn; } + break; + } - if (credits_left < capacity) - capacity = credits_left; + return done; +} - pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false); - done += pfns; - *last_pfn = (dest_pfn + pfns); - if (pfns < capacity) - break; - credits_left -= pfns; +/* + * This releases a chunk of memory and then does the identity map. It's used as + * as a fallback if the remapping fails. + */ +static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn, + unsigned long end_pfn, unsigned long nr_pages, unsigned long *identity, + unsigned long *released) +{ + WARN_ON(start_pfn > end_pfn); + + /* Need to release pages first */ + *released += xen_do_chunk(start_pfn, min(end_pfn, nr_pages), true); + *identity += set_phys_range_identity(start_pfn, end_pfn); +} + +/* + * Helper function to update both the p2m and m2p tables. + */ +static unsigned long __init xen_update_mem_tables(unsigned long pfn, + unsigned long mfn) +{ + struct mmu_update update = { + .ptr = ((unsigned long long)mfn << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE, + .val = pfn + }; + + /* Update p2m */ + if (!early_set_phys_to_machine(pfn, mfn)) { + WARN(1, "Failed to set p2m mapping for pfn=%ld mfn=%ld\n", + pfn, mfn); + return false; } - return done; + + /* Update m2p */ + if (HYPERVISOR_mmu_update(&update, 1, NULL, DOMID_SELF) < 0) { + WARN(1, "Failed to set m2p mapping for mfn=%ld pfn=%ld\n", + mfn, pfn); + return false; + } + + return true; } -static void __init xen_set_identity_and_release_chunk( - unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages, - unsigned long *released, unsigned long *identity) +/* + * This function updates the p2m and m2p tables with an identity map from + * start_pfn to start_pfn+size and remaps the underlying RAM of the original + * allocation at remap_pfn. It must do so carefully in P2M_PER_PAGE sized blocks + * to not exhaust the reserved brk space. Doing it in properly aligned blocks + * ensures we only allocate the minimum required leaf pages in the p2m table. It + * copies the existing mfns from the p2m table under the 1:1 map, overwrites + * them with the identity map and then updates the p2m and m2p tables with the + * remapped memory. + */ +static unsigned long __init xen_do_set_identity_and_remap_chunk( + unsigned long start_pfn, unsigned long size, unsigned long remap_pfn) { - unsigned long pfn; + unsigned long ident_pfn_iter, remap_pfn_iter; + unsigned long ident_start_pfn_align, remap_start_pfn_align; + unsigned long ident_end_pfn_align, remap_end_pfn_align; + unsigned long ident_boundary_pfn, remap_boundary_pfn; + unsigned long ident_cnt = 0; + unsigned long remap_cnt = 0; + unsigned long left = size; + unsigned long mod; + int i; + + WARN_ON(size == 0); + + BUG_ON(xen_feature(XENFEAT_auto_translated_physmap)); /* - * If the PFNs are currently mapped, clear the mappings - * (except for the ISA region which must be 1:1 mapped) to - * release the refcounts (in Xen) on the original frames. + * Determine the proper alignment to remap memory in P2M_PER_PAGE sized + * blocks. We need to keep track of both the existing pfn mapping and + * the new pfn remapping. */ - for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) { - pte_t pte = __pte_ma(0); + mod = start_pfn % P2M_PER_PAGE; + ident_start_pfn_align = + mod ? (start_pfn - mod + P2M_PER_PAGE) : start_pfn; + mod = remap_pfn % P2M_PER_PAGE; + remap_start_pfn_align = + mod ? (remap_pfn - mod + P2M_PER_PAGE) : remap_pfn; + mod = (start_pfn + size) % P2M_PER_PAGE; + ident_end_pfn_align = start_pfn + size - mod; + mod = (remap_pfn + size) % P2M_PER_PAGE; + remap_end_pfn_align = remap_pfn + size - mod; + + /* Iterate over each p2m leaf node in each range */ + for (ident_pfn_iter = ident_start_pfn_align, remap_pfn_iter = remap_start_pfn_align; + ident_pfn_iter < ident_end_pfn_align && remap_pfn_iter < remap_end_pfn_align; + ident_pfn_iter += P2M_PER_PAGE, remap_pfn_iter += P2M_PER_PAGE) { + /* Check we aren't past the end */ + BUG_ON(ident_pfn_iter + P2M_PER_PAGE > start_pfn + size); + BUG_ON(remap_pfn_iter + P2M_PER_PAGE > remap_pfn + size); + + /* Save p2m mappings */ + for (i = 0; i < P2M_PER_PAGE; i++) + xen_remap_buf[i] = pfn_to_mfn(ident_pfn_iter + i); + + /* Set identity map which will free a p2m leaf */ + ident_cnt += set_phys_range_identity(ident_pfn_iter, + ident_pfn_iter + P2M_PER_PAGE); + +#ifdef DEBUG + /* Helps verify a p2m leaf has been freed */ + for (i = 0; i < P2M_PER_PAGE; i++) { + unsigned int pfn = ident_pfn_iter + i; + BUG_ON(pfn_to_mfn(pfn) != pfn); + } +#endif + /* Now remap memory */ + for (i = 0; i < P2M_PER_PAGE; i++) { + unsigned long mfn = xen_remap_buf[i]; + + /* This will use the p2m leaf freed above */ + if (!xen_update_mem_tables(remap_pfn_iter + i, mfn)) { + WARN(1, "Failed to update mem mapping for pfn=%ld mfn=%ld\n", + remap_pfn_iter + i, mfn); + return 0; + } + + remap_cnt++; + } - if (pfn < PFN_UP(ISA_END_ADDRESS)) - pte = mfn_pte(pfn, PAGE_KERNEL_IO); + left -= P2M_PER_PAGE; + } - (void)HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), pte, 0); + /* Max boundary space possible */ + BUG_ON(left > (P2M_PER_PAGE - 1) * 2); + + /* Now handle the boundary conditions */ + ident_boundary_pfn = start_pfn; + remap_boundary_pfn = remap_pfn; + for (i = 0; i < left; i++) { + unsigned long mfn; + + /* These two checks move from the start to end boundaries */ + if (ident_boundary_pfn == ident_start_pfn_align) + ident_boundary_pfn = ident_pfn_iter; + if (remap_boundary_pfn == remap_start_pfn_align) + remap_boundary_pfn = remap_pfn_iter; + + /* Check we aren't past the end */ + BUG_ON(ident_boundary_pfn >= start_pfn + size); + BUG_ON(remap_boundary_pfn >= remap_pfn + size); + + mfn = pfn_to_mfn(ident_boundary_pfn); + + if (!xen_update_mem_tables(remap_boundary_pfn, mfn)) { + WARN(1, "Failed to update mem mapping for pfn=%ld mfn=%ld\n", + remap_pfn_iter + i, mfn); + return 0; + } + remap_cnt++; + + ident_boundary_pfn++; + remap_boundary_pfn++; } - if (start_pfn < nr_pages) - *released += xen_release_chunk( - start_pfn, min(end_pfn, nr_pages)); + /* Finish up the identity map */ + if (ident_start_pfn_align >= ident_end_pfn_align) { + /* + * In this case we have an identity range which does not span an + * aligned block so everything needs to be identity mapped here. + * If we didn't check this we might remap too many pages since + * the align boundaries are not meaningful in this case. + */ + ident_cnt += set_phys_range_identity(start_pfn, + start_pfn + size); + } else { + /* Remapped above so check each end of the chunk */ + if (start_pfn < ident_start_pfn_align) + ident_cnt += set_phys_range_identity(start_pfn, + ident_start_pfn_align); + if (start_pfn + size > ident_pfn_iter) + ident_cnt += set_phys_range_identity(ident_pfn_iter, + start_pfn + size); + } - *identity += set_phys_range_identity(start_pfn, end_pfn); + BUG_ON(ident_cnt != size); + BUG_ON(remap_cnt != size); + + return size; } -static unsigned long __init xen_set_identity_and_release( - const struct e820entry *list, size_t map_size, unsigned long nr_pages) +/* + * This function takes a contiguous pfn range that needs to be identity mapped + * and: + * + * 1) Finds a new range of pfns to use to remap based on E820 and remap_pfn. + * 2) Calls the do_ function to actually do the mapping/remapping work. + * + * The goal is to not allocate additional memory but to remap the existing + * pages. In the case of an error the underlying memory is simply released back + * to Xen and not remapped. + */ +static unsigned long __init xen_set_identity_and_remap_chunk( + const struct e820entry *list, size_t map_size, unsigned long start_pfn, + unsigned long end_pfn, unsigned long nr_pages, unsigned long remap_pfn, + unsigned long *identity, unsigned long *remapped, + unsigned long *released) +{ + unsigned long pfn; + unsigned long i = 0; + unsigned long n = end_pfn - start_pfn; + + while (i < n) { + unsigned long cur_pfn = start_pfn + i; + unsigned long left = n - i; + unsigned long size = left; + unsigned long remap_range_size; + + /* Do not remap pages beyond the current allocation */ + if (cur_pfn >= nr_pages) { + /* Identity map remaining pages */ + *identity += set_phys_range_identity(cur_pfn, + cur_pfn + size); + break; + } + if (cur_pfn + size > nr_pages) + size = nr_pages - cur_pfn; + + remap_range_size = xen_find_pfn_range(list, map_size, + &remap_pfn); + if (!remap_range_size) { + pr_warning("Unable to find available pfn range, not remapping identity pages\n"); + xen_set_identity_and_release_chunk(cur_pfn, + cur_pfn + left, nr_pages, identity, released); + break; + } + /* Adjust size to fit in current e820 RAM region */ + if (size > remap_range_size) + size = remap_range_size; + + if (!xen_do_set_identity_and_remap_chunk(cur_pfn, size, remap_pfn)) { + WARN(1, "Failed to remap 1:1 memory cur_pfn=%ld size=%ld remap_pfn=%ld\n", + cur_pfn, size, remap_pfn); + xen_set_identity_and_release_chunk(cur_pfn, + cur_pfn + left, nr_pages, identity, released); + break; + } + + /* Update variables to reflect new mappings. */ + i += size; + remap_pfn += size; + *identity += size; + *remapped += size; + } + + /* + * If the PFNs are currently mapped, the VA mapping also needs + * to be updated to be 1:1. + */ + for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) + (void)HYPERVISOR_update_va_mapping( + (unsigned long)__va(pfn << PAGE_SHIFT), + mfn_pte(pfn, PAGE_KERNEL_IO), 0); + + return remap_pfn; +} + +static unsigned long __init xen_set_identity_and_remap( + const struct e820entry *list, size_t map_size, unsigned long nr_pages, + unsigned long *released) { phys_addr_t start = 0; - unsigned long released = 0; unsigned long identity = 0; + unsigned long remapped = 0; + unsigned long last_pfn = nr_pages; const struct e820entry *entry; + unsigned long num_released = 0; int i; /* * Combine non-RAM regions and gaps until a RAM region (or the * end of the map) is reached, then set the 1:1 map and - * release the pages (if available) in those non-RAM regions. + * remap the memory in those non-RAM regions. * * The combined non-RAM regions are rounded to a whole number * of pages so any partial pages are accessible via the 1:1 @@ -269,22 +491,24 @@ static unsigned long __init xen_set_identity_and_release( end_pfn = PFN_UP(entry->addr); if (start_pfn < end_pfn) - xen_set_identity_and_release_chunk( - start_pfn, end_pfn, nr_pages, - &released, &identity); - + last_pfn = xen_set_identity_and_remap_chunk( + list, map_size, start_pfn, + end_pfn, nr_pages, last_pfn, + &identity, &remapped, + &num_released); start = end; } } - if (released) - printk(KERN_INFO "Released %lu pages of unused memory\n", released); - if (identity) - printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity); + *released = num_released; - return released; -} + pr_info("Set %ld page(s) to 1-1 mapping\n", identity); + pr_info("Remapped %ld page(s), last_pfn=%ld\n", remapped, + last_pfn); + pr_info("Released %ld page(s)\n", num_released); + return last_pfn; +} static unsigned long __init xen_get_max_pages(void) { unsigned long max_pages = MAX_DOMAIN_PAGES; @@ -347,7 +571,6 @@ char * __init xen_memory_setup(void) unsigned long max_pages; unsigned long last_pfn = 0; unsigned long extra_pages = 0; - unsigned long populated; int i; int op; @@ -392,20 +615,11 @@ char * __init xen_memory_setup(void) extra_pages += max_pages - max_pfn; /* - * Set P2M for all non-RAM pages and E820 gaps to be identity - * type PFNs. Any RAM pages that would be made inaccesible by - * this are first released. + * Set identity map on non-RAM pages and remap the underlying RAM. */ - xen_released_pages = xen_set_identity_and_release( - map, memmap.nr_entries, max_pfn); - - /* - * Populate back the non-RAM pages and E820 gaps that had been - * released. */ - populated = xen_populate_chunk(map, memmap.nr_entries, - max_pfn, &last_pfn, xen_released_pages); + last_pfn = xen_set_identity_and_remap(map, memmap.nr_entries, max_pfn, + &xen_released_pages); - xen_released_pages -= populated; extra_pages += xen_released_pages; if (last_pfn > max_pfn) { |