diff options
Diffstat (limited to 'arch/x86/xen/p2m.c')
| -rw-r--r-- | arch/x86/xen/p2m.c | 1426 |
1 files changed, 592 insertions, 834 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 95fb2aa5927e..2dd12b61a230 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -1,23 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 + /* * Xen leaves the responsibility for maintaining p2m mappings to the * guests themselves, but it must also access and update the p2m array * during suspend/resume when all the pages are reallocated. * - * The p2m table is logically a flat array, but we implement it as a - * three-level tree to allow the address space to be sparse. + * The logical flat p2m table is mapped to a linear kernel memory area. + * For accesses by Xen a three-level tree linked via mfns only is set up to + * allow the address space to be sparse. * - * Xen - * | - * p2m_top p2m_top_mfn - * / \ / \ - * p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn - * / \ / \ / / - * p2m p2m p2m p2m p2m p2m p2m ... + * Xen + * | + * p2m_top_mfn + * / \ + * p2m_mid_mfn p2m_mid_mfn + * / / + * p2m p2m p2m ... * * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p. * - * The p2m_top and p2m_top_mfn levels are limited to 1 page, so the - * maximum representable pseudo-physical address space is: + * The p2m_top_mfn level is limited to 1 page, so the maximum representable + * pseudo-physical address space is: * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages * * P2M_PER_PAGE depends on the architecture, as a mfn is always @@ -30,176 +33,96 @@ * leaf entries, or for the top root, or middle one, for which there is a void * entry, we assume it is "missing". So (for example) * pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY. + * We have a dedicated page p2m_missing with all entries being + * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m + * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns. * * We also have the possibility of setting 1-1 mappings on certain regions, so * that: * pfn_to_mfn(0xc0000)=0xc0000 * * The benefit of this is, that we can assume for non-RAM regions (think - * PCI BARs, or ACPI spaces), we can create mappings easily b/c we + * PCI BARs, or ACPI spaces), we can create mappings easily because we * get the PFN value to match the MFN. * - * For this to work efficiently we have one new page p2m_identity and - * allocate (via reserved_brk) any other pages we need to cover the sides - * (1GB or 4MB boundary violations). All entries in p2m_identity are set to - * INVALID_P2M_ENTRY type (Xen toolstack only recognizes that and MFNs, - * no other fancy value). + * For this to work efficiently we have one new page p2m_identity. All entries + * in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only + * recognizes that and MFNs, no other fancy value). * * On lookup we spot that the entry points to p2m_identity and return the * identity value instead of dereferencing and returning INVALID_P2M_ENTRY. * If the entry points to an allocated page, we just proceed as before and - * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in + * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in * appropriate functions (pfn_to_mfn). * * The reason for having the IDENTITY_FRAME_BIT instead of just returning the * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a * non-identity pfn. To protect ourselves against we elect to set (and get) the * IDENTITY_FRAME_BIT on all identity mapped PFNs. - * - * This simplistic diagram is used to explain the more subtle piece of code. - * There is also a digram of the P2M at the end that can help. - * Imagine your E820 looking as so: - * - * 1GB 2GB - * /-------------------+---------\/----\ /----------\ /---+-----\ - * | System RAM | Sys RAM ||ACPI| | reserved | | Sys RAM | - * \-------------------+---------/\----/ \----------/ \---+-----/ - * ^- 1029MB ^- 2001MB - * - * [1029MB = 263424 (0x40500), 2001MB = 512256 (0x7D100), - * 2048MB = 524288 (0x80000)] - * - * And dom0_mem=max:3GB,1GB is passed in to the guest, meaning memory past 1GB - * is actually not present (would have to kick the balloon driver to put it in). - * - * When we are told to set the PFNs for identity mapping (see patch: "xen/setup: - * Set identity mapping for non-RAM E820 and E820 gaps.") we pass in the start - * of the PFN and the end PFN (263424 and 512256 respectively). The first step - * is to reserve_brk a top leaf page if the p2m[1] is missing. The top leaf page - * covers 512^2 of page estate (1GB) and in case the start or end PFN is not - * aligned on 512^2*PAGE_SIZE (1GB) we loop on aligned 1GB PFNs from start pfn - * to end pfn. We reserve_brk top leaf pages if they are missing (means they - * point to p2m_mid_missing). - * - * With the E820 example above, 263424 is not 1GB aligned so we allocate a - * reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000. - * Each entry in the allocate page is "missing" (points to p2m_missing). - * - * Next stage is to determine if we need to do a more granular boundary check - * on the 4MB (or 2MB depending on architecture) off the start and end pfn's. - * We check if the start pfn and end pfn violate that boundary check, and if - * so reserve_brk a middle (p2m[x][y]) leaf page. This way we have a much finer - * granularity of setting which PFNs are missing and which ones are identity. - * In our example 263424 and 512256 both fail the check so we reserve_brk two - * pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing" - * values) and assign them to p2m[1][2] and p2m[1][488] respectively. - * - * At this point we would at minimum reserve_brk one page, but could be up to - * three. Each call to set_phys_range_identity has at maximum a three page - * cost. If we were to query the P2M at this stage, all those entries from - * start PFN through end PFN (so 1029MB -> 2001MB) would return - * INVALID_P2M_ENTRY ("missing"). - * - * The next step is to walk from the start pfn to the end pfn setting - * the IDENTITY_FRAME_BIT on each PFN. This is done in set_phys_range_identity. - * If we find that the middle leaf is pointing to p2m_missing we can swap it - * over to p2m_identity - this way covering 4MB (or 2MB) PFN space. At this - * point we do not need to worry about boundary aligment (so no need to - * reserve_brk a middle page, figure out which PFNs are "missing" and which - * ones are identity), as that has been done earlier. If we find that the - * middle leaf is not occupied by p2m_identity or p2m_missing, we dereference - * that page (which covers 512 PFNs) and set the appropriate PFN with - * IDENTITY_FRAME_BIT. In our example 263424 and 512256 end up there, and we - * set from p2m[1][2][256->511] and p2m[1][488][0->256] with - * IDENTITY_FRAME_BIT set. - * - * All other regions that are void (or not filled) either point to p2m_missing - * (considered missing) or have the default value of INVALID_P2M_ENTRY (also - * considered missing). In our case, p2m[1][2][0->255] and p2m[1][488][257->511] - * contain the INVALID_P2M_ENTRY value and are considered "missing." - * - * This is what the p2m ends up looking (for the E820 above) with this - * fabulous drawing: - * - * p2m /--------------\ - * /-----\ | &mfn_list[0],| /-----------------\ - * | 0 |------>| &mfn_list[1],| /---------------\ | ~0, ~0, .. | - * |-----| | ..., ~0, ~0 | | ~0, ~0, [x]---+----->| IDENTITY [@256] | - * | 1 |---\ \--------------/ | [p2m_identity]+\ | IDENTITY [@257] | - * |-----| \ | [p2m_identity]+\\ | .... | - * | 2 |--\ \-------------------->| ... | \\ \----------------/ - * |-----| \ \---------------/ \\ - * | 3 |\ \ \\ p2m_identity - * |-----| \ \-------------------->/---------------\ /-----------------\ - * | .. +->+ | [p2m_identity]+-->| ~0, ~0, ~0, ... | - * \-----/ / | [p2m_identity]+-->| ..., ~0 | - * / /---------------\ | .... | \-----------------/ - * / | IDENTITY[@0] | /-+-[x], ~0, ~0.. | - * / | IDENTITY[@256]|<----/ \---------------/ - * / | ~0, ~0, .... | - * | \---------------/ - * | - * p2m_mid_missing p2m_missing - * /-----------------\ /------------\ - * | [p2m_missing] +---->| ~0, ~0, ~0 | - * | [p2m_missing] +---->| ..., ~0 | - * \-----------------/ \------------/ - * - * where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT) */ #include <linux/init.h> -#include <linux/module.h> +#include <linux/export.h> #include <linux/list.h> #include <linux/hash.h> #include <linux/sched.h> #include <linux/seq_file.h> +#include <linux/memblock.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/acpi.h> #include <asm/cache.h> #include <asm/setup.h> +#include <linux/uaccess.h> #include <asm/xen/page.h> #include <asm/xen/hypercall.h> #include <asm/xen/hypervisor.h> +#include <xen/balloon.h> #include <xen/grant_table.h> +#include <xen/hvc-console.h> -#include "multicalls.h" #include "xen-ops.h" -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) +#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); -static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE); +#define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) -static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE); -static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE); -static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE); +unsigned long *xen_p2m_addr __read_mostly; +EXPORT_SYMBOL_GPL(xen_p2m_addr); +unsigned long xen_p2m_size __read_mostly; +EXPORT_SYMBOL_GPL(xen_p2m_size); +unsigned long xen_max_p2m_pfn __read_mostly; +EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); -static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE); +#ifdef CONFIG_XEN_MEMORY_HOTPLUG_LIMIT +#define P2M_LIMIT CONFIG_XEN_MEMORY_HOTPLUG_LIMIT +#else +#define P2M_LIMIT 0 +#endif -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))); +static DEFINE_SPINLOCK(p2m_update_lock); -/* 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_identity, PAGE_SIZE * 2 * 3); +static unsigned long *p2m_mid_missing_mfn; +static unsigned long *p2m_top_mfn; +static unsigned long **p2m_top_mfn_p; +static unsigned long *p2m_missing; +static unsigned long *p2m_identity; +static pte_t *p2m_missing_pte; +static pte_t *p2m_identity_pte; -/* 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); +/* + * Hint at last populated PFN. + * + * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack + * can avoid scanning the whole P2M (which may be sized to account for + * hotplugged memory). + */ +static unsigned long xen_p2m_last_pfn; static inline unsigned p2m_top_index(unsigned long pfn) { @@ -212,19 +135,6 @@ static inline unsigned p2m_mid_index(unsigned long pfn) return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; } -static inline unsigned p2m_index(unsigned long pfn) -{ - return pfn % P2M_PER_PAGE; -} - -static void p2m_top_init(unsigned long ***top) -{ - unsigned i; - - for (i = 0; i < P2M_TOP_PER_PAGE; i++) - top[i] = p2m_mid_missing; -} - static void p2m_top_mfn_init(unsigned long *top) { unsigned i; @@ -241,73 +151,101 @@ static void p2m_top_mfn_p_init(unsigned long **top) top[i] = p2m_mid_missing_mfn; } -static void p2m_mid_init(unsigned long **mid) +static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) { unsigned i; for (i = 0; i < P2M_MID_PER_PAGE; i++) - mid[i] = p2m_missing; + mid[i] = virt_to_mfn(leaf); } -static void p2m_mid_mfn_init(unsigned long *mid) +static void p2m_init(unsigned long *p2m) { unsigned i; - for (i = 0; i < P2M_MID_PER_PAGE; i++) - mid[i] = virt_to_mfn(p2m_missing); + for (i = 0; i < P2M_PER_PAGE; i++) + p2m[i] = INVALID_P2M_ENTRY; } -static void p2m_init(unsigned long *p2m) +static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) { unsigned i; - for (i = 0; i < P2M_MID_PER_PAGE; i++) - p2m[i] = INVALID_P2M_ENTRY; + for (i = 0; i < P2M_PER_PAGE; i++) + p2m[i] = IDENTITY_FRAME(pfn + i); +} + +static void * __ref alloc_p2m_page(void) +{ + if (unlikely(!slab_is_available())) { + return memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE); + } + + return (void *)__get_free_page(GFP_KERNEL); +} + +static void __ref free_p2m_page(void *p) +{ + if (unlikely(!slab_is_available())) { + memblock_free(p, PAGE_SIZE); + return; + } + + free_page((unsigned long)p); } /* * Build the parallel p2m_top_mfn and p2m_mid_mfn structures * * This is called both at boot time, and after resuming from suspend: - * - At boot time we're called very early, and must use extend_brk() + * - At boot time we're called rather early, and must use alloc_bootmem*() * to allocate memory. * * - After resume we're called from within stop_machine, but the mfn - * tree should alreay be completely allocated. + * tree should already be completely allocated. */ void __ref xen_build_mfn_list_list(void) { - unsigned long pfn; + unsigned long pfn, mfn; + pte_t *ptep; + unsigned int level, topidx, mididx; + unsigned long *mid_mfn_p; + + if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) + return; /* Pre-initialize p2m_top_mfn to be completely missing */ if (p2m_top_mfn == NULL) { - p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_mid_mfn_init(p2m_mid_missing_mfn); + p2m_mid_missing_mfn = alloc_p2m_page(); + p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); - p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_top_mfn_p = alloc_p2m_page(); p2m_top_mfn_p_init(p2m_top_mfn_p); - p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_top_mfn = alloc_p2m_page(); p2m_top_mfn_init(p2m_top_mfn); } else { /* Reinitialise, mfn's all change after migration */ - p2m_mid_mfn_init(p2m_mid_missing_mfn); + p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); } - for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) { - unsigned topidx = p2m_top_index(pfn); - unsigned mididx = p2m_mid_index(pfn); - unsigned long **mid; - unsigned long *mid_mfn_p; + for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN; + pfn += P2M_PER_PAGE) { + topidx = p2m_top_index(pfn); + mididx = p2m_mid_index(pfn); - mid = p2m_top[topidx]; mid_mfn_p = p2m_top_mfn_p[topidx]; + ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), + &level); + BUG_ON(!ptep || level != PG_LEVEL_4K); + mfn = pte_mfn(*ptep); + ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); /* Don't bother allocating any mfn mid levels if * they're just missing, just update the stored mfn, * since all could have changed over a migrate. */ - if (mid == p2m_mid_missing) { + if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { BUG_ON(mididx); BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); @@ -316,20 +254,14 @@ void __ref xen_build_mfn_list_list(void) } if (mid_mfn_p == p2m_mid_missing_mfn) { - /* - * XXX boot-time only! We should never find - * missing parts of the mfn tree after - * runtime. extend_brk() will BUG if we call - * it too late. - */ - mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_mid_mfn_init(mid_mfn_p); + mid_mfn_p = alloc_p2m_page(); + p2m_mid_mfn_init(mid_mfn_p, p2m_missing); p2m_top_mfn_p[topidx] = mid_mfn_p; } p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); - mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]); + mid_mfn_p[mididx] = mfn; } } @@ -337,822 +269,651 @@ void xen_setup_mfn_list_list(void) { BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); - HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = - virt_to_mfn(p2m_top_mfn); - HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; + if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) + HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL; + else + HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = + virt_to_mfn(p2m_top_mfn); + HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; + HYPERVISOR_shared_info->arch.p2m_generation = 0; + HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr; + HYPERVISOR_shared_info->arch.p2m_cr3 = + xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); } /* Set up p2m_top to point to the domain-builder provided p2m pages */ void __init xen_build_dynamic_phys_to_machine(void) { - unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list; - unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages); unsigned long pfn; - xen_max_p2m_pfn = max_pfn; - - p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_init(p2m_missing); + xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; + xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); - p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_mid_init(p2m_mid_missing); + for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) + xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; - p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_top_init(p2m_top); + xen_max_p2m_pfn = xen_p2m_size; +} - p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_init(p2m_identity); +#define P2M_TYPE_IDENTITY 0 +#define P2M_TYPE_MISSING 1 +#define P2M_TYPE_PFN 2 +#define P2M_TYPE_UNKNOWN 3 - /* - * The domain builder gives us a pre-constructed p2m array in - * mfn_list for all the pages initially given to us, so we just - * need to graft that into our tree structure. - */ - for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) { - unsigned topidx = p2m_top_index(pfn); - unsigned mididx = p2m_mid_index(pfn); +static int xen_p2m_elem_type(unsigned long pfn) +{ + unsigned long mfn; - if (p2m_top[topidx] == p2m_mid_missing) { - unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_mid_init(mid); + if (pfn >= xen_p2m_size) + return P2M_TYPE_IDENTITY; - p2m_top[topidx] = mid; - } + mfn = xen_p2m_addr[pfn]; - /* - * As long as the mfn_list has enough entries to completely - * fill a p2m page, pointing into the array is ok. But if - * not the entries beyond the last pfn will be undefined. - */ - if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) { - unsigned long p2midx; + if (mfn == INVALID_P2M_ENTRY) + return P2M_TYPE_MISSING; - p2midx = max_pfn % P2M_PER_PAGE; - for ( ; p2midx < P2M_PER_PAGE; p2midx++) - mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY; - } - p2m_top[topidx][mididx] = &mfn_list[pfn]; - } + if (mfn & IDENTITY_FRAME_BIT) + return P2M_TYPE_IDENTITY; - m2p_override_init(); + return P2M_TYPE_PFN; } -#ifdef CONFIG_X86_64 -#include <linux/bootmem.h> -unsigned long __init xen_revector_p2m_tree(void) + +static void __init xen_rebuild_p2m_list(unsigned long *p2m) { - unsigned long va_start; - unsigned long va_end; + unsigned int i, chunk; unsigned long pfn; - unsigned long pfn_free = 0; - unsigned long *mfn_list = NULL; - unsigned long size; - - va_start = xen_start_info->mfn_list; - /*We copy in increments of P2M_PER_PAGE * sizeof(unsigned long), - * so make sure it is rounded up to that */ - size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); - va_end = va_start + size; - - /* If we were revectored already, don't do it again. */ - if (va_start <= __START_KERNEL_map && va_start >= __PAGE_OFFSET) - return 0; + unsigned long *mfns; + pte_t *ptep; + pmd_t *pmdp; + int type; - mfn_list = alloc_bootmem_align(size, PAGE_SIZE); - if (!mfn_list) { - pr_warn("Could not allocate space for a new P2M tree!\n"); - return xen_start_info->mfn_list; - } - /* Fill it out with INVALID_P2M_ENTRY value */ - memset(mfn_list, 0xFF, size); + p2m_missing = alloc_p2m_page(); + p2m_init(p2m_missing); + p2m_identity = alloc_p2m_page(); + p2m_init(p2m_identity); - for (pfn = 0; pfn < ALIGN(MAX_DOMAIN_PAGES, P2M_PER_PAGE); pfn += P2M_PER_PAGE) { - unsigned topidx = p2m_top_index(pfn); - unsigned mididx; - unsigned long *mid_p; + p2m_missing_pte = alloc_p2m_page(); + paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT); + p2m_identity_pte = alloc_p2m_page(); + paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT); + for (i = 0; i < PTRS_PER_PTE; i++) { + set_pte(p2m_missing_pte + i, + pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO)); + set_pte(p2m_identity_pte + i, + pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO)); + } - if (!p2m_top[topidx]) + for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { + /* + * Try to map missing/identity PMDs or p2m-pages if possible. + * We have to respect the structure of the mfn_list_list + * which will be built just afterwards. + * Chunk size to test is one p2m page if we are in the middle + * of a mfn_list_list mid page and the complete mid page area + * if we are at index 0 of the mid page. Please note that a + * mid page might cover more than one PMD, e.g. on 32 bit PAE + * kernels. + */ + chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? + P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; + + type = xen_p2m_elem_type(pfn); + i = 0; + if (type != P2M_TYPE_PFN) + for (i = 1; i < chunk; i++) + if (xen_p2m_elem_type(pfn + i) != type) + break; + if (i < chunk) + /* Reset to minimal chunk size. */ + chunk = P2M_PER_PAGE; + + if (type == P2M_TYPE_PFN || i < chunk) { + /* Use initial p2m page contents. */ + mfns = alloc_p2m_page(); + copy_page(mfns, xen_p2m_addr + pfn); + ptep = populate_extra_pte((unsigned long)(p2m + pfn)); + set_pte(ptep, + pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); continue; + } - if (p2m_top[topidx] == p2m_mid_missing) + if (chunk == P2M_PER_PAGE) { + /* Map complete missing or identity p2m-page. */ + mfns = (type == P2M_TYPE_MISSING) ? + p2m_missing : p2m_identity; + ptep = populate_extra_pte((unsigned long)(p2m + pfn)); + set_pte(ptep, + pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); continue; + } - mididx = p2m_mid_index(pfn); - mid_p = p2m_top[topidx][mididx]; - if (!mid_p) - continue; - if ((mid_p == p2m_missing) || (mid_p == p2m_identity)) - continue; + /* Complete missing or identity PMD(s) can be mapped. */ + ptep = (type == P2M_TYPE_MISSING) ? + p2m_missing_pte : p2m_identity_pte; + for (i = 0; i < PMDS_PER_MID_PAGE; i++) { + pmdp = populate_extra_pmd( + (unsigned long)(p2m + pfn) + i * PMD_SIZE); + set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE)); + } + } +} - if ((unsigned long)mid_p == INVALID_P2M_ENTRY) - continue; +void __init xen_vmalloc_p2m_tree(void) +{ + static struct vm_struct vm; + unsigned long p2m_limit; - /* The old va. Rebase it on mfn_list */ - if (mid_p >= (unsigned long *)va_start && mid_p <= (unsigned long *)va_end) { - unsigned long *new; + xen_p2m_last_pfn = xen_max_p2m_pfn; - if (pfn_free > (size / sizeof(unsigned long))) { - WARN(1, "Only allocated for %ld pages, but we want %ld!\n", - size / sizeof(unsigned long), pfn_free); - return 0; - } - new = &mfn_list[pfn_free]; + p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; + vm.flags = VM_ALLOC; + vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), + PMD_SIZE * PMDS_PER_MID_PAGE); + vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); + pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); - copy_page(new, mid_p); - p2m_top[topidx][mididx] = &mfn_list[pfn_free]; - p2m_top_mfn_p[topidx][mididx] = virt_to_mfn(&mfn_list[pfn_free]); + xen_max_p2m_pfn = vm.size / sizeof(unsigned long); - pfn_free += P2M_PER_PAGE; + xen_rebuild_p2m_list(vm.addr); - } - /* This should be the leafs allocated for identity from _brk. */ - } - return (unsigned long)mfn_list; + xen_p2m_addr = vm.addr; + xen_p2m_size = xen_max_p2m_pfn; + xen_inv_extra_mem(); } -#else -unsigned long __init xen_revector_p2m_tree(void) -{ - return 0; -} -#endif + unsigned long get_phys_to_machine(unsigned long pfn) { - unsigned topidx, mididx, idx; + pte_t *ptep; + unsigned int level; + + if (unlikely(pfn >= xen_p2m_size)) { + if (pfn < xen_max_p2m_pfn) + return xen_chk_extra_mem(pfn); - if (unlikely(pfn >= MAX_P2M_PFN)) - return INVALID_P2M_ENTRY; + return IDENTITY_FRAME(pfn); + } - topidx = p2m_top_index(pfn); - mididx = p2m_mid_index(pfn); - idx = p2m_index(pfn); + ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); + BUG_ON(!ptep || level != PG_LEVEL_4K); /* * The INVALID_P2M_ENTRY is filled in both p2m_*identity * and in p2m_*missing, so returning the INVALID_P2M_ENTRY * would be wrong. */ - if (p2m_top[topidx][mididx] == p2m_identity) + if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) return IDENTITY_FRAME(pfn); - return p2m_top[topidx][mididx][idx]; + return xen_p2m_addr[pfn]; } EXPORT_SYMBOL_GPL(get_phys_to_machine); -static void *alloc_p2m_page(void) -{ - return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT); -} - -static void free_p2m_page(void *p) -{ - free_page((unsigned long)p); -} - /* - * Fully allocate the p2m structure for a given pfn. We need to check - * that both the top and mid levels are allocated, and make sure the - * parallel mfn tree is kept in sync. We may race with other cpus, so - * the new pages are installed with cmpxchg; if we lose the race then - * simply free the page we allocated and use the one that's there. + * Allocate new pmd(s). It is checked whether the old pmd is still in place. + * If not, nothing is changed. This is okay as the only reason for allocating + * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual + * pmd. */ -static bool alloc_p2m(unsigned long pfn) +static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) { - unsigned topidx, mididx; - unsigned long ***top_p, **mid; - unsigned long *top_mfn_p, *mid_mfn; - - topidx = p2m_top_index(pfn); - mididx = p2m_mid_index(pfn); - - top_p = &p2m_top[topidx]; - mid = *top_p; - - if (mid == p2m_mid_missing) { - /* Mid level is missing, allocate a new one */ - mid = alloc_p2m_page(); - if (!mid) - return false; - - p2m_mid_init(mid); - - if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing) - free_p2m_page(mid); - } - - top_mfn_p = &p2m_top_mfn[topidx]; - mid_mfn = p2m_top_mfn_p[topidx]; - - BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); - - if (mid_mfn == p2m_mid_missing_mfn) { - /* Separately check the mid mfn level */ - unsigned long missing_mfn; - unsigned long mid_mfn_mfn; - - mid_mfn = alloc_p2m_page(); - if (!mid_mfn) - return false; - - p2m_mid_mfn_init(mid_mfn); - - missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); - mid_mfn_mfn = virt_to_mfn(mid_mfn); - if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn) - free_p2m_page(mid_mfn); - else - p2m_top_mfn_p[topidx] = mid_mfn; - } - - if (p2m_top[topidx][mididx] == p2m_identity || - p2m_top[topidx][mididx] == p2m_missing) { - /* p2m leaf page is missing */ - unsigned long *p2m; - unsigned long *p2m_orig = p2m_top[topidx][mididx]; - - p2m = alloc_p2m_page(); - if (!p2m) - return false; + pte_t *ptechk; + pte_t *pte_newpg[PMDS_PER_MID_PAGE]; + pmd_t *pmdp; + unsigned int level; + unsigned long flags; + unsigned long vaddr; + int i; - p2m_init(p2m); + /* Do all allocations first to bail out in error case. */ + for (i = 0; i < PMDS_PER_MID_PAGE; i++) { + pte_newpg[i] = alloc_p2m_page(); + if (!pte_newpg[i]) { + for (i--; i >= 0; i--) + free_p2m_page(pte_newpg[i]); - if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig) - free_p2m_page(p2m); - else - mid_mfn[mididx] = virt_to_mfn(p2m); + return NULL; + } } - return true; -} - -static bool __init early_alloc_p2m_middle(unsigned long pfn, bool check_boundary) -{ - unsigned topidx, mididx, idx; - unsigned long *p2m; - unsigned long *mid_mfn_p; - - topidx = p2m_top_index(pfn); - mididx = p2m_mid_index(pfn); - idx = p2m_index(pfn); - - /* Pfff.. No boundary cross-over, lets get out. */ - if (!idx && check_boundary) - return false; - - WARN(p2m_top[topidx][mididx] == p2m_identity, - "P2M[%d][%d] == IDENTITY, should be MISSING (or alloced)!\n", - topidx, mididx); - - /* - * Could be done by xen_build_dynamic_phys_to_machine.. - */ - if (p2m_top[topidx][mididx] != p2m_missing) - return false; - - /* Boundary cross-over for the edges: */ - p2m = extend_brk(PAGE_SIZE, PAGE_SIZE); - - p2m_init(p2m); - - p2m_top[topidx][mididx] = p2m; + vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); - /* For save/restore we need to MFN of the P2M saved */ + for (i = 0; i < PMDS_PER_MID_PAGE; i++) { + copy_page(pte_newpg[i], pte_pg); + paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT); - mid_mfn_p = p2m_top_mfn_p[topidx]; - WARN(mid_mfn_p[mididx] != virt_to_mfn(p2m_missing), - "P2M_TOP_P[%d][%d] != MFN of p2m_missing!\n", - topidx, mididx); - mid_mfn_p[mididx] = virt_to_mfn(p2m); + pmdp = lookup_pmd_address(vaddr); + BUG_ON(!pmdp); - return true; -} - -static bool __init early_alloc_p2m(unsigned long pfn) -{ - unsigned topidx = p2m_top_index(pfn); - unsigned long *mid_mfn_p; - unsigned long **mid; + spin_lock_irqsave(&p2m_update_lock, flags); - mid = p2m_top[topidx]; - mid_mfn_p = p2m_top_mfn_p[topidx]; - if (mid == p2m_mid_missing) { - mid = extend_brk(PAGE_SIZE, PAGE_SIZE); + ptechk = lookup_address(vaddr, &level); + if (ptechk == pte_pg) { + HYPERVISOR_shared_info->arch.p2m_generation++; + wmb(); /* Tools are synchronizing via p2m_generation. */ + set_pmd(pmdp, + __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); + wmb(); /* Tools are synchronizing via p2m_generation. */ + HYPERVISOR_shared_info->arch.p2m_generation++; + pte_newpg[i] = NULL; + } - p2m_mid_init(mid); + spin_unlock_irqrestore(&p2m_update_lock, flags); - p2m_top[topidx] = mid; + if (pte_newpg[i]) { + paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); + free_p2m_page(pte_newpg[i]); + } - BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); + vaddr += PMD_SIZE; } - /* And the save/restore P2M tables.. */ - if (mid_mfn_p == p2m_mid_missing_mfn) { - mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); - p2m_mid_mfn_init(mid_mfn_p); - p2m_top_mfn_p[topidx] = mid_mfn_p; - p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); - /* Note: we don't set mid_mfn_p[midix] here, - * look in early_alloc_p2m_middle */ - } - return true; + return lookup_address(addr, &level); } /* - * Skim over the P2M tree looking at pages that are either filled with - * INVALID_P2M_ENTRY or with 1:1 PFNs. If found, re-use that page and - * replace the P2M leaf with a p2m_missing or p2m_identity. - * Stick the old page in the new P2M tree location. + * Fully allocate the p2m structure for a given pfn. We need to check + * that both the top and mid levels are allocated, and make sure the + * parallel mfn tree is kept in sync. We may race with other cpus, so + * the new pages are installed with cmpxchg; if we lose the race then + * simply free the page we allocated and use the one that's there. */ -bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_mfn) +int xen_alloc_p2m_entry(unsigned long pfn) { unsigned topidx; - unsigned mididx; - unsigned ident_pfns; - unsigned inv_pfns; - unsigned long *p2m; - unsigned long *mid_mfn_p; - unsigned idx; - unsigned long pfn; - - /* We only look when this entails a P2M middle layer */ - if (p2m_index(set_pfn)) - return false; + unsigned long *top_mfn_p, *mid_mfn; + pte_t *ptep, *pte_pg; + unsigned int level; + unsigned long flags; + unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); + unsigned long p2m_pfn; + + ptep = lookup_address(addr, &level); + BUG_ON(!ptep || level != PG_LEVEL_4K); + pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); + + if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { + /* PMD level is missing, allocate a new one */ + ptep = alloc_p2m_pmd(addr, pte_pg); + if (!ptep) + return -ENOMEM; + } - for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_PER_PAGE) { + if (p2m_top_mfn && pfn < MAX_P2M_PFN) { topidx = p2m_top_index(pfn); + top_mfn_p = &p2m_top_mfn[topidx]; + mid_mfn = READ_ONCE(p2m_top_mfn_p[topidx]); + + BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); + + if (mid_mfn == p2m_mid_missing_mfn) { + /* Separately check the mid mfn level */ + unsigned long missing_mfn; + unsigned long mid_mfn_mfn; + + mid_mfn = alloc_p2m_page(); + if (!mid_mfn) + return -ENOMEM; + + p2m_mid_mfn_init(mid_mfn, p2m_missing); + + missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); + mid_mfn_mfn = virt_to_mfn(mid_mfn); + /* try_cmpxchg() updates missing_mfn on failure. */ + if (try_cmpxchg(top_mfn_p, &missing_mfn, mid_mfn_mfn)) { + p2m_top_mfn_p[topidx] = mid_mfn; + } else { + free_p2m_page(mid_mfn); + mid_mfn = mfn_to_virt(missing_mfn); + } + } + } else { + mid_mfn = NULL; + } - if (!p2m_top[topidx]) - continue; - - if (p2m_top[topidx] == p2m_mid_missing) - continue; + p2m_pfn = pte_pfn(READ_ONCE(*ptep)); + if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) || + p2m_pfn == PFN_DOWN(__pa(p2m_missing))) { + /* p2m leaf page is missing */ + unsigned long *p2m; - mididx = p2m_mid_index(pfn); - p2m = p2m_top[topidx][mididx]; + p2m = alloc_p2m_page(); if (!p2m) - continue; - - if ((p2m == p2m_missing) || (p2m == p2m_identity)) - continue; - - if ((unsigned long)p2m == INVALID_P2M_ENTRY) - continue; + return -ENOMEM; - ident_pfns = 0; - inv_pfns = 0; - for (idx = 0; idx < P2M_PER_PAGE; idx++) { - /* IDENTITY_PFNs are 1:1 */ - if (p2m[idx] == IDENTITY_FRAME(pfn + idx)) - ident_pfns++; - else if (p2m[idx] == INVALID_P2M_ENTRY) - inv_pfns++; - else - break; + if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) + p2m_init(p2m); + else + p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); + + spin_lock_irqsave(&p2m_update_lock, flags); + + if (pte_pfn(*ptep) == p2m_pfn) { + HYPERVISOR_shared_info->arch.p2m_generation++; + wmb(); /* Tools are synchronizing via p2m_generation. */ + set_pte(ptep, + pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); + wmb(); /* Tools are synchronizing via p2m_generation. */ + HYPERVISOR_shared_info->arch.p2m_generation++; + if (mid_mfn) + mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m); + p2m = NULL; } - if ((ident_pfns == P2M_PER_PAGE) || (inv_pfns == P2M_PER_PAGE)) - goto found; - } - return false; -found: - /* Found one, replace old with p2m_identity or p2m_missing */ - p2m_top[topidx][mididx] = (ident_pfns ? p2m_identity : p2m_missing); - /* And the other for save/restore.. */ - mid_mfn_p = p2m_top_mfn_p[topidx]; - /* NOTE: Even if it is a p2m_identity it should still be point to - * a page filled with INVALID_P2M_ENTRY entries. */ - mid_mfn_p[mididx] = virt_to_mfn(p2m_missing); - - /* Reset where we want to stick the old page in. */ - topidx = p2m_top_index(set_pfn); - mididx = p2m_mid_index(set_pfn); - - /* This shouldn't happen */ - if (WARN_ON(p2m_top[topidx] == p2m_mid_missing)) - early_alloc_p2m(set_pfn); - - if (WARN_ON(p2m_top[topidx][mididx] != p2m_missing)) - return false; - - p2m_init(p2m); - p2m_top[topidx][mididx] = p2m; - mid_mfn_p = p2m_top_mfn_p[topidx]; - mid_mfn_p[mididx] = virt_to_mfn(p2m); - return true; -} -bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn) -{ - if (unlikely(!__set_phys_to_machine(pfn, mfn))) { - if (!early_alloc_p2m(pfn)) - return false; - - if (early_can_reuse_p2m_middle(pfn, mfn)) - return __set_phys_to_machine(pfn, mfn); + spin_unlock_irqrestore(&p2m_update_lock, flags); - if (!early_alloc_p2m_middle(pfn, false /* boundary crossover OK!*/)) - return false; + if (p2m) + free_p2m_page(p2m); + } - if (!__set_phys_to_machine(pfn, mfn)) - return false; + /* Expanded the p2m? */ + if (pfn >= xen_p2m_last_pfn) { + xen_p2m_last_pfn = ALIGN(pfn + 1, P2M_PER_PAGE); + HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; } - return true; + return 0; } +EXPORT_SYMBOL(xen_alloc_p2m_entry); + unsigned long __init set_phys_range_identity(unsigned long pfn_s, unsigned long pfn_e) { unsigned long pfn; - if (unlikely(pfn_s >= MAX_P2M_PFN || pfn_e >= MAX_P2M_PFN)) + if (unlikely(pfn_s >= xen_p2m_size)) return 0; - if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) - return pfn_e - pfn_s; - if (pfn_s > pfn_e) return 0; - for (pfn = (pfn_s & ~(P2M_MID_PER_PAGE * P2M_PER_PAGE - 1)); - pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE)); - pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE) - { - WARN_ON(!early_alloc_p2m(pfn)); - } - - early_alloc_p2m_middle(pfn_s, true); - early_alloc_p2m_middle(pfn_e, true); + if (pfn_e > xen_p2m_size) + pfn_e = xen_p2m_size; for (pfn = pfn_s; pfn < pfn_e; pfn++) - if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn))) - break; - - if (!WARN((pfn - pfn_s) != (pfn_e - pfn_s), - "Identity mapping failed. We are %ld short of 1-1 mappings!\n", - (pfn_e - pfn_s) - (pfn - pfn_s))) - printk(KERN_DEBUG "1-1 mapping on %lx->%lx\n", pfn_s, pfn); + xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); return pfn - pfn_s; } -/* Try to install p2m mapping; fail if intermediate bits missing */ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) { - unsigned topidx, mididx, idx; - - if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) { - BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY); - return true; - } - if (unlikely(pfn >= MAX_P2M_PFN)) { - BUG_ON(mfn != INVALID_P2M_ENTRY); - return true; - } + pte_t *ptep; + unsigned int level; - topidx = p2m_top_index(pfn); - mididx = p2m_mid_index(pfn); - idx = p2m_index(pfn); + /* Only invalid entries allowed above the highest p2m covered frame. */ + if (unlikely(pfn >= xen_p2m_size)) + return mfn == INVALID_P2M_ENTRY; - /* For sparse holes were the p2m leaf has real PFN along with - * PCI holes, stick in the PFN as the MFN value. + /* + * The interface requires atomic updates on p2m elements. + * xen_safe_write_ulong() is using an atomic store via asm(). */ - if (mfn != INVALID_P2M_ENTRY && (mfn & IDENTITY_FRAME_BIT)) { - if (p2m_top[topidx][mididx] == p2m_identity) - return true; - - /* Swap over from MISSING to IDENTITY if needed. */ - if (p2m_top[topidx][mididx] == p2m_missing) { - WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing, - p2m_identity) != p2m_missing); - return true; - } - } + if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) + return true; - if (p2m_top[topidx][mididx] == p2m_missing) + ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); + BUG_ON(!ptep || level != PG_LEVEL_4K); + + if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) return mfn == INVALID_P2M_ENTRY; - p2m_top[topidx][mididx][idx] = mfn; + if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) + return mfn == IDENTITY_FRAME(pfn); - return true; + return false; } bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) { - if (unlikely(!__set_phys_to_machine(pfn, mfn))) { - if (!alloc_p2m(pfn)) - return false; + if (unlikely(!__set_phys_to_machine(pfn, mfn))) { + int ret; - if (!__set_phys_to_machine(pfn, mfn)) + ret = xen_alloc_p2m_entry(pfn); + if (ret < 0) return false; + + return __set_phys_to_machine(pfn, mfn); } return true; } -#define M2P_OVERRIDE_HASH_SHIFT 10 -#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT) - -static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH); -static DEFINE_SPINLOCK(m2p_override_lock); - -static void __init m2p_override_init(void) +int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count) { - unsigned i; + int i, ret = 0; + pte_t *pte; - m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, - sizeof(unsigned long)); + if (!xen_pv_domain()) + return 0; - for (i = 0; i < M2P_OVERRIDE_HASH; i++) - INIT_LIST_HEAD(&m2p_overrides[i]); -} + if (kmap_ops) { + ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, + kmap_ops, count); + if (ret) + goto out; + } -static unsigned long mfn_hash(unsigned long mfn) -{ - return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT); -} + for (i = 0; i < count; i++) { + unsigned long mfn, pfn; + struct gnttab_unmap_grant_ref unmap[2]; + int rc; -/* Add an MFN override for a particular page */ -int m2p_add_override(unsigned long mfn, struct page *page, - struct gnttab_map_grant_ref *kmap_op) -{ - unsigned long flags; - unsigned long pfn; - unsigned long uninitialized_var(address); - unsigned level; - pte_t *ptep = NULL; - int ret = 0; - - pfn = page_to_pfn(page); - if (!PageHighMem(page)) { - address = (unsigned long)__va(pfn << PAGE_SHIFT); - ptep = lookup_address(address, &level); - if (WARN(ptep == NULL || level != PG_LEVEL_4K, - "m2p_add_override: pfn %lx not mapped", pfn)) - return -EINVAL; - } - WARN_ON(PagePrivate(page)); - SetPagePrivate(page); - set_page_private(page, mfn); - page->index = pfn_to_mfn(pfn); + /* Do not add to override if the map failed. */ + if (map_ops[i].status != GNTST_okay || + (kmap_ops && kmap_ops[i].status != GNTST_okay)) + continue; - if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) - return -ENOMEM; + if (map_ops[i].flags & GNTMAP_contains_pte) { + pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + + (map_ops[i].host_addr & ~PAGE_MASK)); + mfn = pte_mfn(*pte); + } else { + mfn = PFN_DOWN(map_ops[i].dev_bus_addr); + } + pfn = page_to_pfn(pages[i]); - if (kmap_op != NULL) { - if (!PageHighMem(page)) { - struct multicall_space mcs = - xen_mc_entry(sizeof(*kmap_op)); + WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); - MULTI_grant_table_op(mcs.mc, - GNTTABOP_map_grant_ref, kmap_op, 1); + if (likely(set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) + continue; - xen_mc_issue(PARAVIRT_LAZY_MMU); + /* + * Signal an error for this slot. This in turn requires + * immediate unmapping. + */ + map_ops[i].status = GNTST_general_error; + unmap[0].host_addr = map_ops[i].host_addr; + unmap[0].handle = map_ops[i].handle; + map_ops[i].handle = INVALID_GRANT_HANDLE; + if (map_ops[i].flags & GNTMAP_device_map) + unmap[0].dev_bus_addr = map_ops[i].dev_bus_addr; + else + unmap[0].dev_bus_addr = 0; + + if (kmap_ops) { + kmap_ops[i].status = GNTST_general_error; + unmap[1].host_addr = kmap_ops[i].host_addr; + unmap[1].handle = kmap_ops[i].handle; + kmap_ops[i].handle = INVALID_GRANT_HANDLE; + if (kmap_ops[i].flags & GNTMAP_device_map) + unmap[1].dev_bus_addr = kmap_ops[i].dev_bus_addr; + else + unmap[1].dev_bus_addr = 0; } - } - spin_lock_irqsave(&m2p_override_lock, flags); - list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]); - spin_unlock_irqrestore(&m2p_override_lock, flags); - - /* p2m(m2p(mfn)) == mfn: the mfn is already present somewhere in - * this domain. Set the FOREIGN_FRAME_BIT in the p2m for the other - * pfn so that the following mfn_to_pfn(mfn) calls will return the - * pfn from the m2p_override (the backend pfn) instead. - * We need to do this because the pages shared by the frontend - * (xen-blkfront) can be already locked (lock_page, called by - * do_read_cache_page); when the userspace backend tries to use them - * with direct_IO, mfn_to_pfn returns the pfn of the frontend, so - * do_blockdev_direct_IO is going to try to lock the same pages - * again resulting in a deadlock. - * As a side effect get_user_pages_fast might not be safe on the - * frontend pages while they are being shared with the backend, - * because mfn_to_pfn (that ends up being called by GUPF) will - * return the backend pfn rather than the frontend pfn. */ - ret = __get_user(pfn, &machine_to_phys_mapping[mfn]); - if (ret == 0 && get_phys_to_machine(pfn) == mfn) - set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)); - return 0; -} -EXPORT_SYMBOL_GPL(m2p_add_override); -int m2p_remove_override(struct page *page, - struct gnttab_map_grant_ref *kmap_op) -{ - unsigned long flags; - unsigned long mfn; - unsigned long pfn; - unsigned long uninitialized_var(address); - unsigned level; - pte_t *ptep = NULL; - int ret = 0; - - pfn = page_to_pfn(page); - mfn = get_phys_to_machine(pfn); - if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) - return -EINVAL; - - if (!PageHighMem(page)) { - address = (unsigned long)__va(pfn << PAGE_SHIFT); - ptep = lookup_address(address, &level); - - if (WARN(ptep == NULL || level != PG_LEVEL_4K, - "m2p_remove_override: pfn %lx not mapped", pfn)) - return -EINVAL; + /* + * Pre-populate both status fields, to be recognizable in + * the log message below. + */ + unmap[0].status = 1; + unmap[1].status = 1; + + rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, + unmap, 1 + !!kmap_ops); + if (rc || unmap[0].status != GNTST_okay || + unmap[1].status != GNTST_okay) + pr_err_once("gnttab unmap failed: rc=%d st0=%d st1=%d\n", + rc, unmap[0].status, unmap[1].status); } - spin_lock_irqsave(&m2p_override_lock, flags); - list_del(&page->lru); - spin_unlock_irqrestore(&m2p_override_lock, flags); - WARN_ON(!PagePrivate(page)); - ClearPagePrivate(page); - - set_phys_to_machine(pfn, page->index); - if (kmap_op != NULL) { - if (!PageHighMem(page)) { - struct multicall_space mcs; - struct gnttab_unmap_grant_ref *unmap_op; - - /* - * It might be that we queued all the m2p grant table - * hypercalls in a multicall, then m2p_remove_override - * get called before the multicall has actually been - * issued. In this case handle is going to -1 because - * it hasn't been modified yet. - */ - if (kmap_op->handle == -1) - xen_mc_flush(); - /* - * Now if kmap_op->handle is negative it means that the - * hypercall actually returned an error. - */ - if (kmap_op->handle == GNTST_general_error) { - printk(KERN_WARNING "m2p_remove_override: " - "pfn %lx mfn %lx, failed to modify kernel mappings", - pfn, mfn); - return -1; - } +out: + return ret; +} - mcs = xen_mc_entry( - sizeof(struct gnttab_unmap_grant_ref)); - unmap_op = mcs.args; - unmap_op->host_addr = kmap_op->host_addr; - unmap_op->handle = kmap_op->handle; - unmap_op->dev_bus_addr = 0; +int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, + struct gnttab_unmap_grant_ref *kunmap_ops, + struct page **pages, unsigned int count) +{ + int i, ret = 0; - MULTI_grant_table_op(mcs.mc, - GNTTABOP_unmap_grant_ref, unmap_op, 1); + if (!xen_pv_domain()) + return 0; - xen_mc_issue(PARAVIRT_LAZY_MMU); + for (i = 0; i < count; i++) { + unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); + unsigned long pfn = page_to_pfn(pages[i]); - set_pte_at(&init_mm, address, ptep, - pfn_pte(pfn, PAGE_KERNEL)); - __flush_tlb_single(address); - kmap_op->host_addr = 0; - } + if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT)) + set_phys_to_machine(pfn, INVALID_P2M_ENTRY); + else + ret = -EINVAL; } + if (kunmap_ops) + ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, + kunmap_ops, count) ?: ret; - /* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present - * somewhere in this domain, even before being added to the - * m2p_override (see comment above in m2p_add_override). - * If there are no other entries in the m2p_override corresponding - * to this mfn, then remove the FOREIGN_FRAME_BIT from the p2m for - * the original pfn (the one shared by the frontend): the backend - * cannot do any IO on this page anymore because it has been - * unshared. Removing the FOREIGN_FRAME_BIT from the p2m entry of - * the original pfn causes mfn_to_pfn(mfn) to return the frontend - * pfn again. */ - mfn &= ~FOREIGN_FRAME_BIT; - ret = __get_user(pfn, &machine_to_phys_mapping[mfn]); - if (ret == 0 && get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) && - m2p_find_override(mfn) == NULL) - set_phys_to_machine(pfn, mfn); - - return 0; + return ret; } -EXPORT_SYMBOL_GPL(m2p_remove_override); -struct page *m2p_find_override(unsigned long mfn) -{ - unsigned long flags; - struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)]; - struct page *p, *ret; +/* Remapped non-RAM areas */ +#define NR_NONRAM_REMAP 4 +static struct nonram_remap { + phys_addr_t maddr; + phys_addr_t paddr; + size_t size; +} xen_nonram_remap[NR_NONRAM_REMAP] __ro_after_init; +static unsigned int nr_nonram_remap __ro_after_init; + +/* + * Do the real remapping of non-RAM regions as specified in the + * xen_nonram_remap[] array. + * In case of an error just crash the system. + */ +void __init xen_do_remap_nonram(void) +{ + unsigned int i; + unsigned int remapped = 0; + const struct nonram_remap *remap = xen_nonram_remap; + unsigned long pfn, mfn, end_pfn; + + for (i = 0; i < nr_nonram_remap; i++) { + end_pfn = PFN_UP(remap->paddr + remap->size); + pfn = PFN_DOWN(remap->paddr); + mfn = PFN_DOWN(remap->maddr); + while (pfn < end_pfn) { + if (!set_phys_to_machine(pfn, mfn)) + panic("Failed to set p2m mapping for pfn=%lx mfn=%lx\n", + pfn, mfn); + + pfn++; + mfn++; + remapped++; + } - ret = NULL; + remap++; + } - spin_lock_irqsave(&m2p_override_lock, flags); + pr_info("Remapped %u non-RAM page(s)\n", remapped); +} - list_for_each_entry(p, bucket, lru) { - if (page_private(p) == mfn) { - ret = p; +#ifdef CONFIG_ACPI +/* + * Xen variant of acpi_os_ioremap() taking potentially remapped non-RAM + * regions into account. + * Any attempt to map an area crossing a remap boundary will produce a + * WARN() splat. + * phys is related to remap->maddr on input and will be rebased to remap->paddr. + */ +static void __iomem *xen_acpi_os_ioremap(acpi_physical_address phys, + acpi_size size) +{ + unsigned int i; + const struct nonram_remap *remap = xen_nonram_remap; + + for (i = 0; i < nr_nonram_remap; i++) { + if (phys + size > remap->maddr && + phys < remap->maddr + remap->size) { + WARN_ON(phys < remap->maddr || + phys + size > remap->maddr + remap->size); + phys += remap->paddr - remap->maddr; break; } } - spin_unlock_irqrestore(&m2p_override_lock, flags); - - return ret; + return x86_acpi_os_ioremap(phys, size); } +#endif /* CONFIG_ACPI */ -unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn) +/* + * Add a new non-RAM remap entry. + * In case of no free entry found, just crash the system. + */ +void __init xen_add_remap_nonram(phys_addr_t maddr, phys_addr_t paddr, + unsigned long size) { - struct page *p = m2p_find_override(mfn); - unsigned long ret = pfn; + BUG_ON((maddr & ~PAGE_MASK) != (paddr & ~PAGE_MASK)); - if (p) - ret = page_to_pfn(p); + if (nr_nonram_remap == NR_NONRAM_REMAP) { + xen_raw_console_write("Number of required E820 entry remapping actions exceed maximum value\n"); + BUG(); + } - return ret; +#ifdef CONFIG_ACPI + /* Switch to the Xen acpi_os_ioremap() variant. */ + if (nr_nonram_remap == 0) + acpi_os_ioremap = xen_acpi_os_ioremap; +#endif + + xen_nonram_remap[nr_nonram_remap].maddr = maddr; + xen_nonram_remap[nr_nonram_remap].paddr = paddr; + xen_nonram_remap[nr_nonram_remap].size = size; + + nr_nonram_remap++; } -EXPORT_SYMBOL_GPL(m2p_find_override_pfn); #ifdef CONFIG_XEN_DEBUG_FS #include <linux/debugfs.h> -#include "debugfs.h" static int p2m_dump_show(struct seq_file *m, void *v) { - static const char * const level_name[] = { "top", "middle", - "entry", "abnormal", "error"}; -#define TYPE_IDENTITY 0 -#define TYPE_MISSING 1 -#define TYPE_PFN 2 -#define TYPE_UNKNOWN 3 static const char * const type_name[] = { - [TYPE_IDENTITY] = "identity", - [TYPE_MISSING] = "missing", - [TYPE_PFN] = "pfn", - [TYPE_UNKNOWN] = "abnormal"}; - unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0; - unsigned int uninitialized_var(prev_level); - unsigned int uninitialized_var(prev_type); - - if (!p2m_top) - return 0; - - for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) { - unsigned topidx = p2m_top_index(pfn); - unsigned mididx = p2m_mid_index(pfn); - unsigned idx = p2m_index(pfn); - unsigned lvl, type; - - lvl = 4; - type = TYPE_UNKNOWN; - if (p2m_top[topidx] == p2m_mid_missing) { - lvl = 0; type = TYPE_MISSING; - } else if (p2m_top[topidx] == NULL) { - lvl = 0; type = TYPE_UNKNOWN; - } else if (p2m_top[topidx][mididx] == NULL) { - lvl = 1; type = TYPE_UNKNOWN; - } else if (p2m_top[topidx][mididx] == p2m_identity) { - lvl = 1; type = TYPE_IDENTITY; - } else if (p2m_top[topidx][mididx] == p2m_missing) { - lvl = 1; type = TYPE_MISSING; - } else if (p2m_top[topidx][mididx][idx] == 0) { - lvl = 2; type = TYPE_UNKNOWN; - } else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) { - lvl = 2; type = TYPE_IDENTITY; - } else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) { - lvl = 2; type = TYPE_MISSING; - } else if (p2m_top[topidx][mididx][idx] == pfn) { - lvl = 2; type = TYPE_PFN; - } else if (p2m_top[topidx][mididx][idx] != pfn) { - lvl = 2; type = TYPE_PFN; - } - if (pfn == 0) { - prev_level = lvl; + [P2M_TYPE_IDENTITY] = "identity", + [P2M_TYPE_MISSING] = "missing", + [P2M_TYPE_PFN] = "pfn", + [P2M_TYPE_UNKNOWN] = "abnormal"}; + unsigned long pfn, first_pfn; + int type, prev_type; + + prev_type = xen_p2m_elem_type(0); + first_pfn = 0; + + for (pfn = 0; pfn < xen_p2m_size; pfn++) { + type = xen_p2m_elem_type(pfn); + if (type != prev_type) { + seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, + type_name[prev_type]); prev_type = type; - } - if (pfn == MAX_DOMAIN_PAGES-1) { - lvl = 3; - type = TYPE_UNKNOWN; - } - if (prev_type != type) { - seq_printf(m, " [0x%lx->0x%lx] %s\n", - prev_pfn_type, pfn, type_name[prev_type]); - prev_pfn_type = pfn; - prev_type = type; - } - if (prev_level != lvl) { - seq_printf(m, " [0x%lx->0x%lx] level %s\n", - prev_pfn_level, pfn, level_name[prev_level]); - prev_pfn_level = pfn; - prev_level = lvl; + first_pfn = pfn; } } + seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, + type_name[prev_type]); return 0; -#undef TYPE_IDENTITY -#undef TYPE_MISSING -#undef TYPE_PFN -#undef TYPE_UNKNOWN } -static int p2m_dump_open(struct inode *inode, struct file *filp) -{ - return single_open(filp, p2m_dump_show, NULL); -} - -static const struct file_operations p2m_dump_fops = { - .open = p2m_dump_open, - .read = seq_read, - .llseek = seq_lseek, - .release = single_release, -}; +DEFINE_SHOW_ATTRIBUTE(p2m_dump); static struct dentry *d_mmu_debug; @@ -1160,9 +921,6 @@ static int __init xen_p2m_debugfs(void) { struct dentry *d_xen = xen_init_debugfs(); - if (d_xen == NULL) - return -ENOMEM; - d_mmu_debug = debugfs_create_dir("mmu", d_xen); debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); |