Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Xen mmu operations |
| 3 | * |
| 4 | * This file contains the various mmu fetch and update operations. |
| 5 | * The most important job they must perform is the mapping between the |
| 6 | * domain's pfn and the overall machine mfns. |
| 7 | * |
| 8 | * Xen allows guests to directly update the pagetable, in a controlled |
| 9 | * fashion. In other words, the guest modifies the same pagetable |
| 10 | * that the CPU actually uses, which eliminates the overhead of having |
| 11 | * a separate shadow pagetable. |
| 12 | * |
| 13 | * In order to allow this, it falls on the guest domain to map its |
| 14 | * notion of a "physical" pfn - which is just a domain-local linear |
| 15 | * address - into a real "machine address" which the CPU's MMU can |
| 16 | * use. |
| 17 | * |
| 18 | * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be |
| 19 | * inserted directly into the pagetable. When creating a new |
| 20 | * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely, |
| 21 | * when reading the content back with __(pgd|pmd|pte)_val, it converts |
| 22 | * the mfn back into a pfn. |
| 23 | * |
| 24 | * The other constraint is that all pages which make up a pagetable |
| 25 | * must be mapped read-only in the guest. This prevents uncontrolled |
| 26 | * guest updates to the pagetable. Xen strictly enforces this, and |
| 27 | * will disallow any pagetable update which will end up mapping a |
| 28 | * pagetable page RW, and will disallow using any writable page as a |
| 29 | * pagetable. |
| 30 | * |
| 31 | * Naively, when loading %cr3 with the base of a new pagetable, Xen |
| 32 | * would need to validate the whole pagetable before going on. |
| 33 | * Naturally, this is quite slow. The solution is to "pin" a |
| 34 | * pagetable, which enforces all the constraints on the pagetable even |
| 35 | * when it is not actively in use. This menas that Xen can be assured |
| 36 | * that it is still valid when you do load it into %cr3, and doesn't |
| 37 | * need to revalidate it. |
| 38 | * |
| 39 | * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 |
| 40 | */ |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 41 | #include <linux/sched.h> |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 42 | #include <linux/highmem.h> |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 43 | #include <linux/bug.h> |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 44 | |
| 45 | #include <asm/pgtable.h> |
| 46 | #include <asm/tlbflush.h> |
| 47 | #include <asm/mmu_context.h> |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 48 | #include <asm/paravirt.h> |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 49 | |
| 50 | #include <asm/xen/hypercall.h> |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 51 | #include <asm/xen/hypervisor.h> |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 52 | |
| 53 | #include <xen/page.h> |
| 54 | #include <xen/interface/xen.h> |
| 55 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 56 | #include "multicalls.h" |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 57 | #include "mmu.h" |
| 58 | |
| 59 | xmaddr_t arbitrary_virt_to_machine(unsigned long address) |
| 60 | { |
| 61 | pte_t *pte = lookup_address(address); |
| 62 | unsigned offset = address & PAGE_MASK; |
| 63 | |
| 64 | BUG_ON(pte == NULL); |
| 65 | |
| 66 | return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset); |
| 67 | } |
| 68 | |
| 69 | void make_lowmem_page_readonly(void *vaddr) |
| 70 | { |
| 71 | pte_t *pte, ptev; |
| 72 | unsigned long address = (unsigned long)vaddr; |
| 73 | |
| 74 | pte = lookup_address(address); |
| 75 | BUG_ON(pte == NULL); |
| 76 | |
| 77 | ptev = pte_wrprotect(*pte); |
| 78 | |
| 79 | if (HYPERVISOR_update_va_mapping(address, ptev, 0)) |
| 80 | BUG(); |
| 81 | } |
| 82 | |
| 83 | void make_lowmem_page_readwrite(void *vaddr) |
| 84 | { |
| 85 | pte_t *pte, ptev; |
| 86 | unsigned long address = (unsigned long)vaddr; |
| 87 | |
| 88 | pte = lookup_address(address); |
| 89 | BUG_ON(pte == NULL); |
| 90 | |
| 91 | ptev = pte_mkwrite(*pte); |
| 92 | |
| 93 | if (HYPERVISOR_update_va_mapping(address, ptev, 0)) |
| 94 | BUG(); |
| 95 | } |
| 96 | |
| 97 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 98 | void xen_set_pmd(pmd_t *ptr, pmd_t val) |
| 99 | { |
Jeremy Fitzhardinge | d66bf8f | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 100 | struct multicall_space mcs; |
| 101 | struct mmu_update *u; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 102 | |
Jeremy Fitzhardinge | d66bf8f | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 103 | preempt_disable(); |
| 104 | |
| 105 | mcs = xen_mc_entry(sizeof(*u)); |
| 106 | u = mcs.args; |
| 107 | u->ptr = virt_to_machine(ptr).maddr; |
| 108 | u->val = pmd_val_ma(val); |
| 109 | MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF); |
| 110 | |
| 111 | xen_mc_issue(PARAVIRT_LAZY_MMU); |
| 112 | |
| 113 | preempt_enable(); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 114 | } |
| 115 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 116 | /* |
| 117 | * Associate a virtual page frame with a given physical page frame |
| 118 | * and protection flags for that frame. |
| 119 | */ |
| 120 | void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) |
| 121 | { |
| 122 | pgd_t *pgd; |
| 123 | pud_t *pud; |
| 124 | pmd_t *pmd; |
| 125 | pte_t *pte; |
| 126 | |
| 127 | pgd = swapper_pg_dir + pgd_index(vaddr); |
| 128 | if (pgd_none(*pgd)) { |
| 129 | BUG(); |
| 130 | return; |
| 131 | } |
| 132 | pud = pud_offset(pgd, vaddr); |
| 133 | if (pud_none(*pud)) { |
| 134 | BUG(); |
| 135 | return; |
| 136 | } |
| 137 | pmd = pmd_offset(pud, vaddr); |
| 138 | if (pmd_none(*pmd)) { |
| 139 | BUG(); |
| 140 | return; |
| 141 | } |
| 142 | pte = pte_offset_kernel(pmd, vaddr); |
| 143 | /* <mfn,flags> stored as-is, to permit clearing entries */ |
| 144 | xen_set_pte(pte, mfn_pte(mfn, flags)); |
| 145 | |
| 146 | /* |
| 147 | * It's enough to flush this one mapping. |
| 148 | * (PGE mappings get flushed as well) |
| 149 | */ |
| 150 | __flush_tlb_one(vaddr); |
| 151 | } |
| 152 | |
| 153 | void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, |
| 154 | pte_t *ptep, pte_t pteval) |
| 155 | { |
Jeremy Fitzhardinge | d66bf8f | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 156 | if (mm == current->mm || mm == &init_mm) { |
Jeremy Fitzhardinge | 8965c1c | 2007-10-16 11:51:29 -0700 | [diff] [blame] | 157 | if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { |
Jeremy Fitzhardinge | d66bf8f | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 158 | struct multicall_space mcs; |
| 159 | mcs = xen_mc_entry(0); |
| 160 | |
| 161 | MULTI_update_va_mapping(mcs.mc, addr, pteval, 0); |
| 162 | xen_mc_issue(PARAVIRT_LAZY_MMU); |
| 163 | return; |
| 164 | } else |
| 165 | if (HYPERVISOR_update_va_mapping(addr, pteval, 0) == 0) |
| 166 | return; |
| 167 | } |
| 168 | xen_set_pte(ptep, pteval); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 169 | } |
| 170 | |
| 171 | #ifdef CONFIG_X86_PAE |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 172 | void xen_set_pud(pud_t *ptr, pud_t val) |
| 173 | { |
Jeremy Fitzhardinge | d66bf8f | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 174 | struct multicall_space mcs; |
| 175 | struct mmu_update *u; |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 176 | |
Jeremy Fitzhardinge | d66bf8f | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 177 | preempt_disable(); |
| 178 | |
| 179 | mcs = xen_mc_entry(sizeof(*u)); |
| 180 | u = mcs.args; |
| 181 | u->ptr = virt_to_machine(ptr).maddr; |
| 182 | u->val = pud_val_ma(val); |
| 183 | MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF); |
| 184 | |
| 185 | xen_mc_issue(PARAVIRT_LAZY_MMU); |
| 186 | |
| 187 | preempt_enable(); |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 188 | } |
| 189 | |
| 190 | void xen_set_pte(pte_t *ptep, pte_t pte) |
| 191 | { |
| 192 | ptep->pte_high = pte.pte_high; |
| 193 | smp_wmb(); |
| 194 | ptep->pte_low = pte.pte_low; |
| 195 | } |
| 196 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 197 | void xen_set_pte_atomic(pte_t *ptep, pte_t pte) |
| 198 | { |
| 199 | set_64bit((u64 *)ptep, pte_val_ma(pte)); |
| 200 | } |
| 201 | |
| 202 | void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) |
| 203 | { |
| 204 | ptep->pte_low = 0; |
| 205 | smp_wmb(); /* make sure low gets written first */ |
| 206 | ptep->pte_high = 0; |
| 207 | } |
| 208 | |
| 209 | void xen_pmd_clear(pmd_t *pmdp) |
| 210 | { |
| 211 | xen_set_pmd(pmdp, __pmd(0)); |
| 212 | } |
| 213 | |
| 214 | unsigned long long xen_pte_val(pte_t pte) |
| 215 | { |
| 216 | unsigned long long ret = 0; |
| 217 | |
| 218 | if (pte.pte_low) { |
| 219 | ret = ((unsigned long long)pte.pte_high << 32) | pte.pte_low; |
| 220 | ret = machine_to_phys(XMADDR(ret)).paddr | 1; |
| 221 | } |
| 222 | |
| 223 | return ret; |
| 224 | } |
| 225 | |
| 226 | unsigned long long xen_pmd_val(pmd_t pmd) |
| 227 | { |
| 228 | unsigned long long ret = pmd.pmd; |
| 229 | if (ret) |
| 230 | ret = machine_to_phys(XMADDR(ret)).paddr | 1; |
| 231 | return ret; |
| 232 | } |
| 233 | |
| 234 | unsigned long long xen_pgd_val(pgd_t pgd) |
| 235 | { |
| 236 | unsigned long long ret = pgd.pgd; |
| 237 | if (ret) |
| 238 | ret = machine_to_phys(XMADDR(ret)).paddr | 1; |
| 239 | return ret; |
| 240 | } |
| 241 | |
| 242 | pte_t xen_make_pte(unsigned long long pte) |
| 243 | { |
| 244 | if (pte & 1) |
| 245 | pte = phys_to_machine(XPADDR(pte)).maddr; |
| 246 | |
| 247 | return (pte_t){ pte, pte >> 32 }; |
| 248 | } |
| 249 | |
| 250 | pmd_t xen_make_pmd(unsigned long long pmd) |
| 251 | { |
| 252 | if (pmd & 1) |
| 253 | pmd = phys_to_machine(XPADDR(pmd)).maddr; |
| 254 | |
| 255 | return (pmd_t){ pmd }; |
| 256 | } |
| 257 | |
| 258 | pgd_t xen_make_pgd(unsigned long long pgd) |
| 259 | { |
| 260 | if (pgd & _PAGE_PRESENT) |
| 261 | pgd = phys_to_machine(XPADDR(pgd)).maddr; |
| 262 | |
| 263 | return (pgd_t){ pgd }; |
| 264 | } |
| 265 | #else /* !PAE */ |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 266 | void xen_set_pte(pte_t *ptep, pte_t pte) |
| 267 | { |
| 268 | *ptep = pte; |
| 269 | } |
| 270 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 271 | unsigned long xen_pte_val(pte_t pte) |
| 272 | { |
| 273 | unsigned long ret = pte.pte_low; |
| 274 | |
| 275 | if (ret & _PAGE_PRESENT) |
| 276 | ret = machine_to_phys(XMADDR(ret)).paddr; |
| 277 | |
| 278 | return ret; |
| 279 | } |
| 280 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 281 | unsigned long xen_pgd_val(pgd_t pgd) |
| 282 | { |
| 283 | unsigned long ret = pgd.pgd; |
| 284 | if (ret) |
| 285 | ret = machine_to_phys(XMADDR(ret)).paddr | 1; |
| 286 | return ret; |
| 287 | } |
| 288 | |
| 289 | pte_t xen_make_pte(unsigned long pte) |
| 290 | { |
| 291 | if (pte & _PAGE_PRESENT) |
| 292 | pte = phys_to_machine(XPADDR(pte)).maddr; |
| 293 | |
| 294 | return (pte_t){ pte }; |
| 295 | } |
| 296 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 297 | pgd_t xen_make_pgd(unsigned long pgd) |
| 298 | { |
| 299 | if (pgd & _PAGE_PRESENT) |
| 300 | pgd = phys_to_machine(XPADDR(pgd)).maddr; |
| 301 | |
| 302 | return (pgd_t){ pgd }; |
| 303 | } |
| 304 | #endif /* CONFIG_X86_PAE */ |
| 305 | |
| 306 | |
| 307 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 308 | /* |
| 309 | (Yet another) pagetable walker. This one is intended for pinning a |
| 310 | pagetable. This means that it walks a pagetable and calls the |
| 311 | callback function on each page it finds making up the page table, |
| 312 | at every level. It walks the entire pagetable, but it only bothers |
| 313 | pinning pte pages which are below pte_limit. In the normal case |
| 314 | this will be TASK_SIZE, but at boot we need to pin up to |
| 315 | FIXADDR_TOP. But the important bit is that we don't pin beyond |
| 316 | there, because then we start getting into Xen's ptes. |
| 317 | */ |
| 318 | static int pgd_walk(pgd_t *pgd_base, int (*func)(struct page *, unsigned), |
| 319 | unsigned long limit) |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 320 | { |
| 321 | pgd_t *pgd = pgd_base; |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 322 | int flush = 0; |
| 323 | unsigned long addr = 0; |
| 324 | unsigned long pgd_next; |
| 325 | |
| 326 | BUG_ON(limit > FIXADDR_TOP); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 327 | |
| 328 | if (xen_feature(XENFEAT_auto_translated_physmap)) |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 329 | return 0; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 330 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 331 | for (; addr != FIXADDR_TOP; pgd++, addr = pgd_next) { |
| 332 | pud_t *pud; |
| 333 | unsigned long pud_limit, pud_next; |
| 334 | |
| 335 | pgd_next = pud_limit = pgd_addr_end(addr, FIXADDR_TOP); |
| 336 | |
| 337 | if (!pgd_val(*pgd)) |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 338 | continue; |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 339 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 340 | pud = pud_offset(pgd, 0); |
| 341 | |
| 342 | if (PTRS_PER_PUD > 1) /* not folded */ |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 343 | flush |= (*func)(virt_to_page(pud), 0); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 344 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 345 | for (; addr != pud_limit; pud++, addr = pud_next) { |
| 346 | pmd_t *pmd; |
| 347 | unsigned long pmd_limit; |
| 348 | |
| 349 | pud_next = pud_addr_end(addr, pud_limit); |
| 350 | |
| 351 | if (pud_next < limit) |
| 352 | pmd_limit = pud_next; |
| 353 | else |
| 354 | pmd_limit = limit; |
| 355 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 356 | if (pud_none(*pud)) |
| 357 | continue; |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 358 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 359 | pmd = pmd_offset(pud, 0); |
| 360 | |
| 361 | if (PTRS_PER_PMD > 1) /* not folded */ |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 362 | flush |= (*func)(virt_to_page(pmd), 0); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 363 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 364 | for (; addr != pmd_limit; pmd++) { |
| 365 | addr += (PAGE_SIZE * PTRS_PER_PTE); |
| 366 | if ((pmd_limit-1) < (addr-1)) { |
| 367 | addr = pmd_limit; |
| 368 | break; |
| 369 | } |
| 370 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 371 | if (pmd_none(*pmd)) |
| 372 | continue; |
| 373 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 374 | flush |= (*func)(pmd_page(*pmd), 0); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 375 | } |
| 376 | } |
| 377 | } |
| 378 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 379 | flush |= (*func)(virt_to_page(pgd_base), UVMF_TLB_FLUSH); |
| 380 | |
| 381 | return flush; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 382 | } |
| 383 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 384 | static int pin_page(struct page *page, unsigned flags) |
| 385 | { |
| 386 | unsigned pgfl = test_and_set_bit(PG_pinned, &page->flags); |
| 387 | int flush; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 388 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 389 | if (pgfl) |
| 390 | flush = 0; /* already pinned */ |
| 391 | else if (PageHighMem(page)) |
| 392 | /* kmaps need flushing if we found an unpinned |
| 393 | highpage */ |
| 394 | flush = 1; |
| 395 | else { |
| 396 | void *pt = lowmem_page_address(page); |
| 397 | unsigned long pfn = page_to_pfn(page); |
| 398 | struct multicall_space mcs = __xen_mc_entry(0); |
| 399 | |
| 400 | flush = 0; |
| 401 | |
| 402 | MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, |
| 403 | pfn_pte(pfn, PAGE_KERNEL_RO), |
| 404 | flags); |
| 405 | } |
| 406 | |
| 407 | return flush; |
| 408 | } |
| 409 | |
| 410 | /* This is called just after a mm has been created, but it has not |
| 411 | been used yet. We need to make sure that its pagetable is all |
| 412 | read-only, and can be pinned. */ |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 413 | void xen_pgd_pin(pgd_t *pgd) |
| 414 | { |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 415 | struct multicall_space mcs; |
| 416 | struct mmuext_op *op; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 417 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 418 | xen_mc_batch(); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 419 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 420 | if (pgd_walk(pgd, pin_page, TASK_SIZE)) { |
| 421 | /* re-enable interrupts for kmap_flush_unused */ |
| 422 | xen_mc_issue(0); |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 423 | kmap_flush_unused(); |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 424 | xen_mc_batch(); |
| 425 | } |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 426 | |
| 427 | mcs = __xen_mc_entry(sizeof(*op)); |
| 428 | op = mcs.args; |
| 429 | |
| 430 | #ifdef CONFIG_X86_PAE |
| 431 | op->cmd = MMUEXT_PIN_L3_TABLE; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 432 | #else |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 433 | op->cmd = MMUEXT_PIN_L2_TABLE; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 434 | #endif |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 435 | op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd))); |
| 436 | MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); |
| 437 | |
| 438 | xen_mc_issue(0); |
| 439 | } |
| 440 | |
| 441 | /* The init_mm pagetable is really pinned as soon as its created, but |
| 442 | that's before we have page structures to store the bits. So do all |
| 443 | the book-keeping now. */ |
| 444 | static __init int mark_pinned(struct page *page, unsigned flags) |
| 445 | { |
| 446 | SetPagePinned(page); |
| 447 | return 0; |
| 448 | } |
| 449 | |
| 450 | void __init xen_mark_init_mm_pinned(void) |
| 451 | { |
| 452 | pgd_walk(init_mm.pgd, mark_pinned, FIXADDR_TOP); |
| 453 | } |
| 454 | |
| 455 | static int unpin_page(struct page *page, unsigned flags) |
| 456 | { |
| 457 | unsigned pgfl = test_and_clear_bit(PG_pinned, &page->flags); |
| 458 | |
| 459 | if (pgfl && !PageHighMem(page)) { |
| 460 | void *pt = lowmem_page_address(page); |
| 461 | unsigned long pfn = page_to_pfn(page); |
| 462 | struct multicall_space mcs = __xen_mc_entry(0); |
| 463 | |
| 464 | MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, |
| 465 | pfn_pte(pfn, PAGE_KERNEL), |
| 466 | flags); |
| 467 | } |
| 468 | |
| 469 | return 0; /* never need to flush on unpin */ |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 470 | } |
| 471 | |
| 472 | /* Release a pagetables pages back as normal RW */ |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 473 | static void xen_pgd_unpin(pgd_t *pgd) |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 474 | { |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 475 | struct mmuext_op *op; |
| 476 | struct multicall_space mcs; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 477 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 478 | xen_mc_batch(); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 479 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 480 | mcs = __xen_mc_entry(sizeof(*op)); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 481 | |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 482 | op = mcs.args; |
| 483 | op->cmd = MMUEXT_UNPIN_TABLE; |
| 484 | op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd))); |
| 485 | |
| 486 | MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); |
| 487 | |
| 488 | pgd_walk(pgd, unpin_page, TASK_SIZE); |
| 489 | |
| 490 | xen_mc_issue(0); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 491 | } |
| 492 | |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 493 | void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next) |
| 494 | { |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 495 | spin_lock(&next->page_table_lock); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 496 | xen_pgd_pin(next->pgd); |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 497 | spin_unlock(&next->page_table_lock); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 498 | } |
| 499 | |
| 500 | void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) |
| 501 | { |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 502 | spin_lock(&mm->page_table_lock); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 503 | xen_pgd_pin(mm->pgd); |
Jeremy Fitzhardinge | f4f97b3 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 504 | spin_unlock(&mm->page_table_lock); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 505 | } |
| 506 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 507 | |
| 508 | #ifdef CONFIG_SMP |
| 509 | /* Another cpu may still have their %cr3 pointing at the pagetable, so |
| 510 | we need to repoint it somewhere else before we can unpin it. */ |
| 511 | static void drop_other_mm_ref(void *info) |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 512 | { |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 513 | struct mm_struct *mm = info; |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 514 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 515 | if (__get_cpu_var(cpu_tlbstate).active_mm == mm) |
| 516 | leave_mm(smp_processor_id()); |
Jeremy Fitzhardinge | 9f79991 | 2007-10-16 11:51:30 -0700 | [diff] [blame^] | 517 | |
| 518 | /* If this cpu still has a stale cr3 reference, then make sure |
| 519 | it has been flushed. */ |
| 520 | if (x86_read_percpu(xen_current_cr3) == __pa(mm->pgd)) { |
| 521 | load_cr3(swapper_pg_dir); |
| 522 | arch_flush_lazy_cpu_mode(); |
| 523 | } |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 524 | } |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 525 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 526 | static void drop_mm_ref(struct mm_struct *mm) |
| 527 | { |
Jeremy Fitzhardinge | 9f79991 | 2007-10-16 11:51:30 -0700 | [diff] [blame^] | 528 | cpumask_t mask; |
| 529 | unsigned cpu; |
| 530 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 531 | if (current->active_mm == mm) { |
| 532 | if (current->mm == mm) |
| 533 | load_cr3(swapper_pg_dir); |
| 534 | else |
| 535 | leave_mm(smp_processor_id()); |
Jeremy Fitzhardinge | 9f79991 | 2007-10-16 11:51:30 -0700 | [diff] [blame^] | 536 | arch_flush_lazy_cpu_mode(); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 537 | } |
| 538 | |
Jeremy Fitzhardinge | 9f79991 | 2007-10-16 11:51:30 -0700 | [diff] [blame^] | 539 | /* Get the "official" set of cpus referring to our pagetable. */ |
| 540 | mask = mm->cpu_vm_mask; |
| 541 | |
| 542 | /* It's possible that a vcpu may have a stale reference to our |
| 543 | cr3, because its in lazy mode, and it hasn't yet flushed |
| 544 | its set of pending hypercalls yet. In this case, we can |
| 545 | look at its actual current cr3 value, and force it to flush |
| 546 | if needed. */ |
| 547 | for_each_online_cpu(cpu) { |
| 548 | if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd)) |
| 549 | cpu_set(cpu, mask); |
| 550 | } |
| 551 | |
| 552 | if (!cpus_empty(mask)) |
| 553 | xen_smp_call_function_mask(mask, drop_other_mm_ref, mm, 1); |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 554 | } |
| 555 | #else |
| 556 | static void drop_mm_ref(struct mm_struct *mm) |
| 557 | { |
| 558 | if (current->active_mm == mm) |
| 559 | load_cr3(swapper_pg_dir); |
| 560 | } |
| 561 | #endif |
| 562 | |
| 563 | /* |
| 564 | * While a process runs, Xen pins its pagetables, which means that the |
| 565 | * hypervisor forces it to be read-only, and it controls all updates |
| 566 | * to it. This means that all pagetable updates have to go via the |
| 567 | * hypervisor, which is moderately expensive. |
| 568 | * |
| 569 | * Since we're pulling the pagetable down, we switch to use init_mm, |
| 570 | * unpin old process pagetable and mark it all read-write, which |
| 571 | * allows further operations on it to be simple memory accesses. |
| 572 | * |
| 573 | * The only subtle point is that another CPU may be still using the |
| 574 | * pagetable because of lazy tlb flushing. This means we need need to |
| 575 | * switch all CPUs off this pagetable before we can unpin it. |
| 576 | */ |
| 577 | void xen_exit_mmap(struct mm_struct *mm) |
| 578 | { |
| 579 | get_cpu(); /* make sure we don't move around */ |
| 580 | drop_mm_ref(mm); |
| 581 | put_cpu(); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 582 | |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 583 | spin_lock(&mm->page_table_lock); |
Jeremy Fitzhardinge | df912ea | 2007-09-25 11:50:00 -0700 | [diff] [blame] | 584 | |
| 585 | /* pgd may not be pinned in the error exit path of execve */ |
| 586 | if (PagePinned(virt_to_page(mm->pgd))) |
| 587 | xen_pgd_unpin(mm->pgd); |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 588 | spin_unlock(&mm->page_table_lock); |
Jeremy Fitzhardinge | 3b827c1 | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 589 | } |