diff options
Diffstat (limited to 'drivers/lguest/page_tables.c')
| -rw-r--r-- | drivers/lguest/page_tables.c | 179 |
1 files changed, 92 insertions, 87 deletions
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index fffabb327157..74b4cf2a6c41 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -68,23 +68,23 @@ 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 * contains the address of the page table entry (PTE) page. It then returns a * pointer to the PTE entry for the given address. */ -static pte_t *spte_addr(struct lguest *lg, pgd_t spgd, unsigned long vaddr) +static pte_t *spte_addr(pgd_t spgd, unsigned long vaddr) { pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT); /* You should never call this if the PGD entry wasn't valid */ @@ -94,14 +94,13 @@ static pte_t *spte_addr(struct lguest *lg, pgd_t spgd, unsigned long vaddr) /* These two functions just like the above two, except they access the Guest * page tables. Hence they return a Guest address. */ -static unsigned long gpgd_addr(struct lguest *lg, unsigned long vaddr) +static unsigned long gpgd_addr(struct lg_cpu *cpu, unsigned long vaddr) { unsigned int index = vaddr >> (PGDIR_SHIFT); - return lg->pgdirs[lg->pgdidx].gpgdir + index * sizeof(pgd_t); + return cpu->lg->pgdirs[cpu->cpu_pgd].gpgdir + index * sizeof(pgd_t); } -static unsigned long gpte_addr(struct lguest *lg, - pgd_t gpgd, unsigned long vaddr) +static unsigned long gpte_addr(pgd_t gpgd, unsigned long vaddr) { unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT; BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT)); @@ -138,7 +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; @@ -149,7 +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 @@ -157,7 +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! */ @@ -177,17 +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 @@ -200,7 +200,7 @@ static void check_gpgd(struct lguest *lg, pgd_t gpgd) * * If we fixed up the fault (ie. we mapped the address), this routine returns * true. Otherwise, it was a real fault and we need to tell the Guest. */ -int demand_page(struct lguest *lg, unsigned long vaddr, int errcode) +int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) { pgd_t gpgd; pgd_t *spgd; @@ -209,24 +209,24 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode) pte_t *spte; /* First step: get the top-level Guest page table entry. */ - gpgd = lgread(lg, gpgd_addr(lg, 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, lg->pgdidx, 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)); @@ -234,8 +234,8 @@ int demand_page(struct lguest *lg, 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(lg, gpgd, vaddr); - gpte = lgread(lg, gpte_ptr, pte_t); + gpte_ptr = gpte_addr(gpgd, vaddr); + 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 lguest *lg, 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); @@ -260,7 +260,7 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode) gpte = pte_mkdirty(gpte); /* Get the pointer to the shadow PTE entry we're going to set. */ - spte = spte_addr(lg, *spgd, vaddr); + spte = spte_addr(*spgd, vaddr); /* If there was a valid shadow PTE entry here before, we release it. * This can happen with a write to a previously read-only entry. */ release_pte(*spte); @@ -268,17 +268,17 @@ int demand_page(struct lguest *lg, 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 @@ -297,19 +297,19 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode) * * This is a quick version which answers the question: is this virtual address * mapped by the shadow page tables, and is it writable? */ -static int page_writable(struct lguest *lg, unsigned long vaddr) +static int page_writable(struct lg_cpu *cpu, unsigned long vaddr) { pgd_t *spgd; unsigned long flags; /* Look at the current top level entry: is it present? */ - spgd = spgd_addr(lg, lg->pgdidx, vaddr); + spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr); if (!(pgd_flags(*spgd) & _PAGE_PRESENT)) return 0; /* Check the flags on the pte entry itself: it must be present and * writable. */ - flags = pte_flags(*(spte_addr(lg, *spgd, vaddr))); + flags = pte_flags(*(spte_addr(*spgd, vaddr))); return (flags & (_PAGE_PRESENT|_PAGE_RW)) == (_PAGE_PRESENT|_PAGE_RW); } @@ -317,10 +317,10 @@ static int page_writable(struct lguest *lg, unsigned long vaddr) /* So, when pin_stack_pages() asks us to pin a page, we check if it's already * in the page tables, and if not, we call demand_page() with error code 2 * (meaning "write"). */ -void pin_page(struct lguest *lg, unsigned long vaddr) +void pin_page(struct lg_cpu *cpu, unsigned long vaddr) { - if (!page_writable(lg, vaddr) && !demand_page(lg, vaddr, 2)) - kill_guest(lg, "bad stack page %#lx", vaddr); + if (!page_writable(cpu, vaddr) && !demand_page(cpu, vaddr, 2)) + kill_guest(cpu, "bad stack page %#lx", vaddr); } /*H:450 If we chase down the release_pgd() code, it looks like this: */ @@ -358,28 +358,28 @@ static void flush_user_mappings(struct lguest *lg, int idx) * * The Guest has a hypercall to throw away the page tables: it's used when a * large number of mappings have been changed. */ -void guest_pagetable_flush_user(struct lguest *lg) +void guest_pagetable_flush_user(struct lg_cpu *cpu) { /* Drop the userspace part of the current page table. */ - flush_user_mappings(lg, lg->pgdidx); + flush_user_mappings(cpu->lg, cpu->cpu_pgd); } /*:*/ /* We walk down the guest page tables to get a guest-physical address */ -unsigned long guest_pa(struct lguest *lg, unsigned long vaddr) +unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr) { pgd_t gpgd; pte_t gpte; /* First step: get the top-level Guest page table entry. */ - gpgd = lgread(lg, gpgd_addr(lg, 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(lg, "Bad address %#lx", vaddr); + kill_guest(cpu, "Bad address %#lx", vaddr); - gpte = lgread(lg, gpte_addr(lg, gpgd, vaddr), pte_t); + gpte = lgread(cpu, gpte_addr(gpgd, vaddr), pte_t); if (!(pte_flags(gpte) & _PAGE_PRESENT)) - kill_guest(lg, "Bad address %#lx", vaddr); + kill_guest(cpu, "Bad address %#lx", vaddr); return pte_pfn(gpte) * PAGE_SIZE | (vaddr & ~PAGE_MASK); } @@ -399,7 +399,7 @@ static unsigned int find_pgdir(struct lguest *lg, unsigned long pgtable) /*H:435 And this is us, creating the new page directory. If we really do * allocate a new one (and so the kernel parts are not there), we set * blank_pgdir. */ -static unsigned int new_pgdir(struct lguest *lg, +static unsigned int new_pgdir(struct lg_cpu *cpu, unsigned long gpgdir, int *blank_pgdir) { @@ -407,22 +407,23 @@ static unsigned int new_pgdir(struct lguest *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) - next = lg->pgdidx; + if (!cpu->lg->pgdirs[next].pgdir) + next = cpu->cpu_pgd; else /* This is a blank page, so there are no kernel * mappings: caller must map the stack! */ *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; } @@ -432,21 +433,21 @@ static unsigned int new_pgdir(struct lguest *lg, * Now we've seen all the page table setting and manipulation, let's see what * what happens when the Guest changes page tables (ie. changes the top-level * pgdir). This occurs on almost every context switch. */ -void guest_new_pagetable(struct lguest *lg, unsigned long pgtable) +void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable) { int newpgdir, repin = 0; /* 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)) - newpgdir = new_pgdir(lg, pgtable, &repin); + if (newpgdir == ARRAY_SIZE(cpu->lg->pgdirs)) + newpgdir = new_pgdir(cpu, pgtable, &repin); /* Change the current pgd index to the new one. */ - lg->pgdidx = newpgdir; + cpu->cpu_pgd = newpgdir; /* If it was completely blank, we map in the Guest kernel stack */ if (repin) - pin_stack_pages(lg); + pin_stack_pages(cpu); } /*H:470 Finally, a routine which throws away everything: all PGD entries in all @@ -468,11 +469,11 @@ static void release_all_pagetables(struct lguest *lg) * mapping. Since kernel mappings are in every page table, it's easiest to * throw them all away. This traps the Guest in amber for a while as * everything faults back in, but it's rare. */ -void guest_pagetable_clear_all(struct lguest *lg) +void guest_pagetable_clear_all(struct lg_cpu *cpu) { - release_all_pagetables(lg); + release_all_pagetables(cpu->lg); /* We need the Guest kernel stack mapped again. */ - pin_stack_pages(lg); + pin_stack_pages(cpu); } /*:*/ /*M:009 Since we throw away all mappings when a kernel mapping changes, our @@ -497,24 +498,24 @@ void guest_pagetable_clear_all(struct lguest *lg) * _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) { /* Otherwise, we start by releasing the existing entry. */ - pte_t *spte = spte_addr(lg, *spgd, vaddr); + pte_t *spte = spte_addr(*spgd, vaddr); release_pte(*spte); /* If they're setting this entry as dirty or accessed, we might * 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 @@ -533,22 +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); } } @@ -590,30 +591,32 @@ int init_guest_pagetable(struct lguest *lg, unsigned long pgtable) { /* We start on the first shadow page table, and give it a blank PGD * page. */ - lg->pgdidx = 0; - lg->pgdirs[lg->pgdidx].gpgdir = pgtable; - lg->pgdirs[lg->pgdidx].pgdir = (pgd_t*)get_zeroed_page(GFP_KERNEL); - if (!lg->pgdirs[lg->pgdidx].pgdir) + lg->pgdirs[0].gpgdir = pgtable; + lg->pgdirs[0].pgdir = (pgd_t *)get_zeroed_page(GFP_KERNEL); + if (!lg->pgdirs[0].pgdir) return -ENOMEM; + lg->cpus[0].cpu_pgd = 0; return 0; } /* 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[lg->pgdidx].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. */ @@ -634,17 +637,18 @@ void free_guest_pagetable(struct lguest *lg) * Guest (and not the pages for other CPUs). We have the appropriate PTE pages * for each CPU already set up, we just need to hook them in now we know which * Guest is about to run on this CPU. */ -void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages) +void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages) { pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages); pgd_t switcher_pgd; pte_t regs_pte; + unsigned long pfn; /* Make the last PGD entry for this Guest point to the Switcher's PTE * page for this CPU (with appropriate flags). */ - switcher_pgd = __pgd(__pa(switcher_pte_page) | _PAGE_KERNEL); + switcher_pgd = __pgd(__pa(switcher_pte_page) | __PAGE_KERNEL); - lg->pgdirs[lg->pgdidx].pgdir[SWITCHER_PGD_INDEX] = switcher_pgd; + cpu->lg->pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX] = switcher_pgd; /* We also change the Switcher PTE page. When we're running the Guest, * we want the Guest's "regs" page to appear where the first Switcher @@ -653,7 +657,8 @@ void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages) * CPU's "struct lguest_pages": if we make sure the Guest's register * page is already mapped there, we don't have to copy them out * again. */ - regs_pte = pfn_pte (__pa(lg->regs_page) >> PAGE_SHIFT, __pgprot(_PAGE_KERNEL)); + pfn = __pa(cpu->regs_page) >> PAGE_SHIFT; + regs_pte = pfn_pte(pfn, __pgprot(__PAGE_KERNEL)); switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTRS_PER_PTE] = regs_pte; } /*:*/ |