| // 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 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_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_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 |
| * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to |
| * 512 and 1024 entries respectively. |
| * |
| * In short, these structures contain the Machine Frame Number (MFN) of the PFN. |
| * |
| * However not all entries are filled with MFNs. Specifically for all other |
| * 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 because we |
| * get the PFN value to match the MFN. |
| * |
| * 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 |
| * 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. |
| */ |
| |
| #include <linux/init.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 <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 "multicalls.h" |
| #include "xen-ops.h" |
| |
| #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 PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) |
| |
| 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); |
| |
| #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT |
| #define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT |
| #else |
| #define P2M_LIMIT 0 |
| #endif |
| |
| static DEFINE_SPINLOCK(p2m_update_lock); |
| |
| 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; |
| |
| /* |
| * 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) |
| { |
| BUG_ON(pfn >= MAX_P2M_PFN); |
| return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); |
| } |
| |
| 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_mfn_init(unsigned long *top) |
| { |
| unsigned i; |
| |
| for (i = 0; i < P2M_TOP_PER_PAGE; i++) |
| top[i] = virt_to_mfn(p2m_mid_missing_mfn); |
| } |
| |
| static void p2m_top_mfn_p_init(unsigned long **top) |
| { |
| unsigned i; |
| |
| for (i = 0; i < P2M_TOP_PER_PAGE; i++) |
| top[i] = p2m_mid_missing_mfn; |
| } |
| |
| 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] = virt_to_mfn(leaf); |
| } |
| |
| static void p2m_init(unsigned long *p2m) |
| { |
| unsigned i; |
| |
| for (i = 0; i < P2M_PER_PAGE; i++) |
| p2m[i] = INVALID_P2M_ENTRY; |
| } |
| |
| static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) |
| { |
| unsigned i; |
| |
| 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())) { |
| void *ptr = memblock_alloc(PAGE_SIZE, PAGE_SIZE); |
| |
| if (!ptr) |
| panic("%s: Failed to allocate %lu bytes align=0x%lx\n", |
| __func__, PAGE_SIZE, PAGE_SIZE); |
| |
| return ptr; |
| } |
| |
| return (void *)__get_free_page(GFP_KERNEL); |
| } |
| |
| static void __ref free_p2m_page(void *p) |
| { |
| if (unlikely(!slab_is_available())) { |
| memblock_free((unsigned long)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 rather early, and must use alloc_bootmem*() |
| * to allocate memory. |
| * |
| * - After resume we're called from within stop_machine, but the mfn |
| * tree should already be completely allocated. |
| */ |
| void __ref xen_build_mfn_list_list(void) |
| { |
| 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 = alloc_p2m_page(); |
| p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); |
| |
| p2m_top_mfn_p = alloc_p2m_page(); |
| p2m_top_mfn_p_init(p2m_top_mfn_p); |
| |
| 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_missing); |
| } |
| |
| 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_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 (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); |
| pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; |
| continue; |
| } |
| |
| if (mid_mfn_p == p2m_mid_missing_mfn) { |
| 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] = mfn; |
| } |
| } |
| |
| void xen_setup_mfn_list_list(void) |
| { |
| BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); |
| |
| 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 pfn; |
| |
| xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; |
| xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); |
| |
| for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) |
| xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; |
| |
| xen_max_p2m_pfn = xen_p2m_size; |
| } |
| |
| #define P2M_TYPE_IDENTITY 0 |
| #define P2M_TYPE_MISSING 1 |
| #define P2M_TYPE_PFN 2 |
| #define P2M_TYPE_UNKNOWN 3 |
| |
| static int xen_p2m_elem_type(unsigned long pfn) |
| { |
| unsigned long mfn; |
| |
| if (pfn >= xen_p2m_size) |
| return P2M_TYPE_IDENTITY; |
| |
| mfn = xen_p2m_addr[pfn]; |
| |
| if (mfn == INVALID_P2M_ENTRY) |
| return P2M_TYPE_MISSING; |
| |
| if (mfn & IDENTITY_FRAME_BIT) |
| return P2M_TYPE_IDENTITY; |
| |
| return P2M_TYPE_PFN; |
| } |
| |
| static void __init xen_rebuild_p2m_list(unsigned long *p2m) |
| { |
| unsigned int i, chunk; |
| unsigned long pfn; |
| unsigned long *mfns; |
| pte_t *ptep; |
| pmd_t *pmdp; |
| int type; |
| |
| p2m_missing = alloc_p2m_page(); |
| p2m_init(p2m_missing); |
| p2m_identity = alloc_p2m_page(); |
| p2m_init(p2m_identity); |
| |
| 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)); |
| } |
| |
| 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. */ |
| #ifdef CONFIG_X86_64 |
| mfns = alloc_p2m_page(); |
| copy_page(mfns, xen_p2m_addr + pfn); |
| #else |
| mfns = xen_p2m_addr + pfn; |
| #endif |
| ptep = populate_extra_pte((unsigned long)(p2m + pfn)); |
| set_pte(ptep, |
| pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); |
| continue; |
| } |
| |
| 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; |
| } |
| |
| /* 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)); |
| } |
| } |
| } |
| |
| void __init xen_vmalloc_p2m_tree(void) |
| { |
| static struct vm_struct vm; |
| unsigned long p2m_limit; |
| |
| xen_p2m_last_pfn = xen_max_p2m_pfn; |
| |
| 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); |
| |
| xen_max_p2m_pfn = vm.size / sizeof(unsigned long); |
| |
| xen_rebuild_p2m_list(vm.addr); |
| |
| xen_p2m_addr = vm.addr; |
| xen_p2m_size = xen_max_p2m_pfn; |
| |
| xen_inv_extra_mem(); |
| } |
| |
| unsigned long get_phys_to_machine(unsigned long pfn) |
| { |
| pte_t *ptep; |
| unsigned int level; |
| |
| if (unlikely(pfn >= xen_p2m_size)) { |
| if (pfn < xen_max_p2m_pfn) |
| return xen_chk_extra_mem(pfn); |
| |
| return IDENTITY_FRAME(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 (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) |
| return IDENTITY_FRAME(pfn); |
| |
| return xen_p2m_addr[pfn]; |
| } |
| EXPORT_SYMBOL_GPL(get_phys_to_machine); |
| |
| /* |
| * 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. In case of PAE/x86-32 there are multiple pmds to allocate! |
| */ |
| static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) |
| { |
| 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; |
| |
| /* 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]); |
| |
| return NULL; |
| } |
| } |
| |
| vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); |
| |
| 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); |
| |
| pmdp = lookup_pmd_address(vaddr); |
| BUG_ON(!pmdp); |
| |
| spin_lock_irqsave(&p2m_update_lock, flags); |
| |
| 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; |
| } |
| |
| spin_unlock_irqrestore(&p2m_update_lock, flags); |
| |
| if (pte_newpg[i]) { |
| paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); |
| free_p2m_page(pte_newpg[i]); |
| } |
| |
| vaddr += PMD_SIZE; |
| } |
| |
| return lookup_address(addr, &level); |
| } |
| |
| /* |
| * 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. |
| */ |
| int xen_alloc_p2m_entry(unsigned long pfn) |
| { |
| unsigned topidx; |
| 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; |
| } |
| |
| 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; |
| unsigned long old_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); |
| old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn); |
| if (old_mfn != missing_mfn) { |
| free_p2m_page(mid_mfn); |
| mid_mfn = mfn_to_virt(old_mfn); |
| } else { |
| p2m_top_mfn_p[topidx] = mid_mfn; |
| } |
| } |
| } else { |
| mid_mfn = NULL; |
| } |
| |
| 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; |
| |
| p2m = alloc_p2m_page(); |
| if (!p2m) |
| return -ENOMEM; |
| |
| 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; |
| } |
| |
| spin_unlock_irqrestore(&p2m_update_lock, flags); |
| |
| if (p2m) |
| free_p2m_page(p2m); |
| } |
| |
| /* Expanded the p2m? */ |
| if (pfn > xen_p2m_last_pfn) { |
| xen_p2m_last_pfn = pfn; |
| HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; |
| } |
| |
| 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 >= xen_p2m_size)) |
| return 0; |
| |
| if (pfn_s > pfn_e) |
| return 0; |
| |
| if (pfn_e > xen_p2m_size) |
| pfn_e = xen_p2m_size; |
| |
| for (pfn = pfn_s; pfn < pfn_e; pfn++) |
| xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); |
| |
| return pfn - pfn_s; |
| } |
| |
| bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) |
| { |
| pte_t *ptep; |
| unsigned int level; |
| |
| if (unlikely(pfn >= xen_p2m_size)) { |
| BUG_ON(mfn != INVALID_P2M_ENTRY); |
| return true; |
| } |
| |
| /* |
| * The interface requires atomic updates on p2m elements. |
| * xen_safe_write_ulong() is using an atomic store via asm(). |
| */ |
| if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) |
| return true; |
| |
| 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; |
| |
| if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) |
| return mfn == IDENTITY_FRAME(pfn); |
| |
| return false; |
| } |
| |
| bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) |
| { |
| if (unlikely(!__set_phys_to_machine(pfn, mfn))) { |
| int ret; |
| |
| ret = xen_alloc_p2m_entry(pfn); |
| if (ret < 0) |
| return false; |
| |
| return __set_phys_to_machine(pfn, mfn); |
| } |
| |
| return true; |
| } |
| |
| 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) |
| { |
| int i, ret = 0; |
| pte_t *pte; |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return 0; |
| |
| if (kmap_ops) { |
| ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, |
| kmap_ops, count); |
| if (ret) |
| goto out; |
| } |
| |
| for (i = 0; i < count; i++) { |
| unsigned long mfn, pfn; |
| |
| /* Do not add to override if the map failed. */ |
| if (map_ops[i].status) |
| continue; |
| |
| 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]); |
| |
| WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); |
| |
| if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| } |
| |
| out: |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); |
| |
| 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; |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return 0; |
| |
| 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]); |
| |
| if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| set_phys_to_machine(pfn, INVALID_P2M_ENTRY); |
| } |
| if (kunmap_ops) |
| ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, |
| kunmap_ops, count); |
| out: |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); |
| |
| #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 type_name[] = { |
| [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; |
| first_pfn = pfn; |
| } |
| } |
| seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, |
| type_name[prev_type]); |
| return 0; |
| } |
| |
| 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, |
| }; |
| |
| static struct dentry *d_mmu_debug; |
| |
| 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); |
| return 0; |
| } |
| fs_initcall(xen_p2m_debugfs); |
| #endif /* CONFIG_XEN_DEBUG_FS */ |