diff options
Diffstat (limited to 'drivers/lguest/page_tables.c')
| -rw-r--r-- | drivers/lguest/page_tables.c | 115 |
1 files changed, 58 insertions, 57 deletions
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index c9acafc..983e902 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -68,17 +68,17 @@ static DEFINE_PER_CPU(pte_t *, switcher_pte_pages); * page directory entry (PGD) for that address. Since we keep track of several * page tables, the "i" argument tells us which one we're interested in (it's * usually the current one). */ -static pgd_t *spgd_addr(struct lguest *lg, u32 i, unsigned long vaddr) +static pgd_t *spgd_addr(struct lg_cpu *cpu, u32 i, unsigned long vaddr) { unsigned int index = pgd_index(vaddr); /* We kill any Guest trying to touch the Switcher addresses. */ if (index >= SWITCHER_PGD_INDEX) { - kill_guest(lg, "attempt to access switcher pages"); + kill_guest(cpu, "attempt to access switcher pages"); index = 0; } /* Return a pointer index'th pgd entry for the i'th page table. */ - return &lg->pgdirs[i].pgdir[index]; + return &cpu->lg->pgdirs[i].pgdir[index]; } /* This routine then takes the page directory entry returned above, which @@ -137,7 +137,7 @@ static unsigned long get_pfn(unsigned long virtpfn, int write) * entry can be a little tricky. The flags are (almost) the same, but the * Guest PTE contains a virtual page number: the CPU needs the real page * number. */ -static pte_t gpte_to_spte(struct lguest *lg, pte_t gpte, int write) +static pte_t gpte_to_spte(struct lg_cpu *cpu, pte_t gpte, int write) { unsigned long pfn, base, flags; @@ -148,7 +148,7 @@ static pte_t gpte_to_spte(struct lguest *lg, pte_t gpte, int write) flags = (pte_flags(gpte) & ~_PAGE_GLOBAL); /* The Guest's pages are offset inside the Launcher. */ - base = (unsigned long)lg->mem_base / PAGE_SIZE; + base = (unsigned long)cpu->lg->mem_base / PAGE_SIZE; /* We need a temporary "unsigned long" variable to hold the answer from * get_pfn(), because it returns 0xFFFFFFFF on failure, which wouldn't @@ -156,7 +156,7 @@ static pte_t gpte_to_spte(struct lguest *lg, pte_t gpte, int write) * page, given the virtual number. */ pfn = get_pfn(base + pte_pfn(gpte), write); if (pfn == -1UL) { - kill_guest(lg, "failed to get page %lu", pte_pfn(gpte)); + kill_guest(cpu, "failed to get page %lu", pte_pfn(gpte)); /* When we destroy the Guest, we'll go through the shadow page * tables and release_pte() them. Make sure we don't think * this one is valid! */ @@ -176,17 +176,18 @@ static void release_pte(pte_t pte) } /*:*/ -static void check_gpte(struct lguest *lg, pte_t gpte) +static void check_gpte(struct lg_cpu *cpu, pte_t gpte) { if ((pte_flags(gpte) & (_PAGE_PWT|_PAGE_PSE)) - || pte_pfn(gpte) >= lg->pfn_limit) - kill_guest(lg, "bad page table entry"); + || pte_pfn(gpte) >= cpu->lg->pfn_limit) + kill_guest(cpu, "bad page table entry"); } -static void check_gpgd(struct lguest *lg, pgd_t gpgd) +static void check_gpgd(struct lg_cpu *cpu, pgd_t gpgd) { - if ((pgd_flags(gpgd) & ~_PAGE_TABLE) || pgd_pfn(gpgd) >= lg->pfn_limit) - kill_guest(lg, "bad page directory entry"); + if ((pgd_flags(gpgd) & ~_PAGE_TABLE) || + (pgd_pfn(gpgd) >= cpu->lg->pfn_limit)) + kill_guest(cpu, "bad page directory entry"); } /*H:330 @@ -206,27 +207,26 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) unsigned long gpte_ptr; pte_t gpte; pte_t *spte; - struct lguest *lg = cpu->lg; /* First step: get the top-level Guest page table entry. */ - gpgd = lgread(lg, gpgd_addr(cpu, vaddr), pgd_t); + gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t); /* Toplevel not present? We can't map it in. */ if (!(pgd_flags(gpgd) & _PAGE_PRESENT)) return 0; /* Now look at the matching shadow entry. */ - spgd = spgd_addr(lg, cpu->cpu_pgd, vaddr); + spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr); if (!(pgd_flags(*spgd) & _PAGE_PRESENT)) { /* No shadow entry: allocate a new shadow PTE page. */ unsigned long ptepage = get_zeroed_page(GFP_KERNEL); /* This is not really the Guest's fault, but killing it is * simple for this corner case. */ if (!ptepage) { - kill_guest(lg, "out of memory allocating pte page"); + kill_guest(cpu, "out of memory allocating pte page"); return 0; } /* We check that the Guest pgd is OK. */ - check_gpgd(lg, gpgd); + check_gpgd(cpu, gpgd); /* And we copy the flags to the shadow PGD entry. The page * number in the shadow PGD is the page we just allocated. */ *spgd = __pgd(__pa(ptepage) | pgd_flags(gpgd)); @@ -235,7 +235,7 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) /* OK, now we look at the lower level in the Guest page table: keep its * address, because we might update it later. */ gpte_ptr = gpte_addr(gpgd, vaddr); - gpte = lgread(lg, gpte_ptr, pte_t); + gpte = lgread(cpu, gpte_ptr, pte_t); /* If this page isn't in the Guest page tables, we can't page it in. */ if (!(pte_flags(gpte) & _PAGE_PRESENT)) @@ -252,7 +252,7 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) /* Check that the Guest PTE flags are OK, and the page number is below * the pfn_limit (ie. not mapping the Launcher binary). */ - check_gpte(lg, gpte); + check_gpte(cpu, gpte); /* Add the _PAGE_ACCESSED and (for a write) _PAGE_DIRTY flag */ gpte = pte_mkyoung(gpte); @@ -268,17 +268,17 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) /* If this is a write, we insist that the Guest page is writable (the * final arg to gpte_to_spte()). */ if (pte_dirty(gpte)) - *spte = gpte_to_spte(lg, gpte, 1); + *spte = gpte_to_spte(cpu, gpte, 1); else /* If this is a read, don't set the "writable" bit in the page * table entry, even if the Guest says it's writable. That way * we will come back here when a write does actually occur, so * we can update the Guest's _PAGE_DIRTY flag. */ - *spte = gpte_to_spte(lg, pte_wrprotect(gpte), 0); + *spte = gpte_to_spte(cpu, pte_wrprotect(gpte), 0); /* Finally, we write the Guest PTE entry back: we've set the * _PAGE_ACCESSED and maybe the _PAGE_DIRTY flags. */ - lgwrite(lg, gpte_ptr, pte_t, gpte); + lgwrite(cpu, gpte_ptr, pte_t, gpte); /* The fault is fixed, the page table is populated, the mapping * manipulated, the result returned and the code complete. A small @@ -303,7 +303,7 @@ static int page_writable(struct lg_cpu *cpu, unsigned long vaddr) unsigned long flags; /* Look at the current top level entry: is it present? */ - spgd = spgd_addr(cpu->lg, cpu->cpu_pgd, vaddr); + spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr); if (!(pgd_flags(*spgd) & _PAGE_PRESENT)) return 0; @@ -320,7 +320,7 @@ static int page_writable(struct lg_cpu *cpu, unsigned long vaddr) void pin_page(struct lg_cpu *cpu, unsigned long vaddr) { if (!page_writable(cpu, vaddr) && !demand_page(cpu, vaddr, 2)) - kill_guest(cpu->lg, "bad stack page %#lx", vaddr); + kill_guest(cpu, "bad stack page %#lx", vaddr); } /*H:450 If we chase down the release_pgd() code, it looks like this: */ @@ -372,14 +372,14 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr) pte_t gpte; /* First step: get the top-level Guest page table entry. */ - gpgd = lgread(cpu->lg, gpgd_addr(cpu, vaddr), pgd_t); + gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t); /* Toplevel not present? We can't map it in. */ if (!(pgd_flags(gpgd) & _PAGE_PRESENT)) - kill_guest(cpu->lg, "Bad address %#lx", vaddr); + kill_guest(cpu, "Bad address %#lx", vaddr); - gpte = lgread(cpu->lg, gpte_addr(gpgd, vaddr), pte_t); + gpte = lgread(cpu, gpte_addr(gpgd, vaddr), pte_t); if (!(pte_flags(gpte) & _PAGE_PRESENT)) - kill_guest(cpu->lg, "Bad address %#lx", vaddr); + kill_guest(cpu, "Bad address %#lx", vaddr); return pte_pfn(gpte) * PAGE_SIZE | (vaddr & ~PAGE_MASK); } @@ -404,16 +404,16 @@ static unsigned int new_pgdir(struct lg_cpu *cpu, int *blank_pgdir) { unsigned int next; - struct lguest *lg = cpu->lg; /* We pick one entry at random to throw out. Choosing the Least * Recently Used might be better, but this is easy. */ - next = random32() % ARRAY_SIZE(lg->pgdirs); + next = random32() % ARRAY_SIZE(cpu->lg->pgdirs); /* If it's never been allocated at all before, try now. */ - if (!lg->pgdirs[next].pgdir) { - lg->pgdirs[next].pgdir = (pgd_t *)get_zeroed_page(GFP_KERNEL); + if (!cpu->lg->pgdirs[next].pgdir) { + cpu->lg->pgdirs[next].pgdir = + (pgd_t *)get_zeroed_page(GFP_KERNEL); /* If the allocation fails, just keep using the one we have */ - if (!lg->pgdirs[next].pgdir) + if (!cpu->lg->pgdirs[next].pgdir) next = cpu->cpu_pgd; else /* This is a blank page, so there are no kernel @@ -421,9 +421,9 @@ static unsigned int new_pgdir(struct lg_cpu *cpu, *blank_pgdir = 1; } /* Record which Guest toplevel this shadows. */ - lg->pgdirs[next].gpgdir = gpgdir; + cpu->lg->pgdirs[next].gpgdir = gpgdir; /* Release all the non-kernel mappings. */ - flush_user_mappings(lg, next); + flush_user_mappings(cpu->lg, next); return next; } @@ -436,13 +436,12 @@ static unsigned int new_pgdir(struct lg_cpu *cpu, void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable) { int newpgdir, repin = 0; - struct lguest *lg = cpu->lg; /* Look to see if we have this one already. */ - newpgdir = find_pgdir(lg, pgtable); + newpgdir = find_pgdir(cpu->lg, pgtable); /* If not, we allocate or mug an existing one: if it's a fresh one, * repin gets set to 1. */ - if (newpgdir == ARRAY_SIZE(lg->pgdirs)) + if (newpgdir == ARRAY_SIZE(cpu->lg->pgdirs)) newpgdir = new_pgdir(cpu, pgtable, &repin); /* Change the current pgd index to the new one. */ cpu->cpu_pgd = newpgdir; @@ -499,11 +498,11 @@ void guest_pagetable_clear_all(struct lg_cpu *cpu) * _PAGE_ACCESSED then we can put a read-only PTE entry in immediately, and if * they set _PAGE_DIRTY then we can put a writable PTE entry in immediately. */ -static void do_set_pte(struct lguest *lg, int idx, +static void do_set_pte(struct lg_cpu *cpu, int idx, unsigned long vaddr, pte_t gpte) { /* Look up the matching shadow page directory entry. */ - pgd_t *spgd = spgd_addr(lg, idx, vaddr); + pgd_t *spgd = spgd_addr(cpu, idx, vaddr); /* If the top level isn't present, there's no entry to update. */ if (pgd_flags(*spgd) & _PAGE_PRESENT) { @@ -515,8 +514,8 @@ static void do_set_pte(struct lguest *lg, int idx, * as well put that entry they've given us in now. This shaves * 10% off a copy-on-write micro-benchmark. */ if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) { - check_gpte(lg, gpte); - *spte = gpte_to_spte(lg, gpte, + check_gpte(cpu, gpte); + *spte = gpte_to_spte(cpu, gpte, pte_flags(gpte) & _PAGE_DIRTY); } else /* Otherwise kill it and we can demand_page() it in @@ -535,22 +534,22 @@ static void do_set_pte(struct lguest *lg, int idx, * * The benefit is that when we have to track a new page table, we can copy keep * all the kernel mappings. This speeds up context switch immensely. */ -void guest_set_pte(struct lguest *lg, +void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir, unsigned long vaddr, pte_t gpte) { /* Kernel mappings must be changed on all top levels. Slow, but * doesn't happen often. */ - if (vaddr >= lg->kernel_address) { + if (vaddr >= cpu->lg->kernel_address) { unsigned int i; - for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++) - if (lg->pgdirs[i].pgdir) - do_set_pte(lg, i, vaddr, gpte); + for (i = 0; i < ARRAY_SIZE(cpu->lg->pgdirs); i++) + if (cpu->lg->pgdirs[i].pgdir) + do_set_pte(cpu, i, vaddr, gpte); } else { /* Is this page table one we have a shadow for? */ - int pgdir = find_pgdir(lg, gpgdir); - if (pgdir != ARRAY_SIZE(lg->pgdirs)) + int pgdir = find_pgdir(cpu->lg, gpgdir); + if (pgdir != ARRAY_SIZE(cpu->lg->pgdirs)) /* If so, do the update. */ - do_set_pte(lg, pgdir, vaddr, gpte); + do_set_pte(cpu, pgdir, vaddr, gpte); } } @@ -601,21 +600,23 @@ int init_guest_pagetable(struct lguest *lg, unsigned long pgtable) } /* When the Guest calls LHCALL_LGUEST_INIT we do more setup. */ -void page_table_guest_data_init(struct lguest *lg) +void page_table_guest_data_init(struct lg_cpu *cpu) { /* We get the kernel address: above this is all kernel memory. */ - if (get_user(lg->kernel_address, &lg->lguest_data->kernel_address) + if (get_user(cpu->lg->kernel_address, + &cpu->lg->lguest_data->kernel_address) /* We tell the Guest that it can't use the top 4MB of virtual * addresses used by the Switcher. */ - || put_user(4U*1024*1024, &lg->lguest_data->reserve_mem) - || put_user(lg->pgdirs[0].gpgdir, &lg->lguest_data->pgdir)) - kill_guest(lg, "bad guest page %p", lg->lguest_data); + || put_user(4U*1024*1024, &cpu->lg->lguest_data->reserve_mem) + || put_user(cpu->lg->pgdirs[0].gpgdir, &cpu->lg->lguest_data->pgdir)) + kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data); /* In flush_user_mappings() we loop from 0 to * "pgd_index(lg->kernel_address)". This assumes it won't hit the * Switcher mappings, so check that now. */ - if (pgd_index(lg->kernel_address) >= SWITCHER_PGD_INDEX) - kill_guest(lg, "bad kernel address %#lx", lg->kernel_address); + if (pgd_index(cpu->lg->kernel_address) >= SWITCHER_PGD_INDEX) + kill_guest(cpu, "bad kernel address %#lx", + cpu->lg->kernel_address); } /* When a Guest dies, our cleanup is fairly simple. */ |