diff options
author | Matias Zabaljauregui <matias.zabaljauregui@cern.ch> | 2007-10-22 11:03:33 +1000 |
---|---|---|
committer | Rusty Russell <rusty@rustcorp.com.au> | 2007-10-23 15:49:53 +1000 |
commit | df29f43e650df29456804dabdb2611de914e7c0f (patch) | |
tree | 2f8de4a2f1b7c4141e710123fc86db266f507d83 /drivers/lguest/page_tables.c | |
parent | 47aee45ae3c708ab678e09abfba0efaf6ca0e87a (diff) |
Pagetables to use normal kernel types
This is my first step in the migration of page_tables.c to the kernel
types and functions/macros (2.6.23-rc3). Seems to be working OK.
Signed-off-by: Matias Zabaljauregui <matias.zabaljauregui@cern.ch>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/lguest/page_tables.c')
-rw-r--r-- | drivers/lguest/page_tables.c | 192 |
1 files changed, 89 insertions, 103 deletions
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index 9cd2faceb87..5c4c53f38cf 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -44,44 +44,32 @@ * (vii) Setting up the page tables initially. :*/ -/* Pages a 4k long, and each page table entry is 4 bytes long, giving us 1024 - * (or 2^10) entries per page. */ -#define PTES_PER_PAGE_SHIFT 10 -#define PTES_PER_PAGE (1 << PTES_PER_PAGE_SHIFT) /* 1024 entries in a page table page maps 1024 pages: 4MB. The Switcher is * conveniently placed at the top 4MB, so it uses a separate, complete PTE * page. */ -#define SWITCHER_PGD_INDEX (PTES_PER_PAGE - 1) +#define SWITCHER_PGD_INDEX (PTRS_PER_PGD - 1) /* We actually need a separate PTE page for each CPU. Remember that after the * Switcher code itself comes two pages for each CPU, and we don't want this * CPU's guest to see the pages of any other CPU. */ -static DEFINE_PER_CPU(spte_t *, switcher_pte_pages); +static DEFINE_PER_CPU(pte_t *, switcher_pte_pages); #define switcher_pte_page(cpu) per_cpu(switcher_pte_pages, cpu) /*H:320 With our shadow and Guest types established, we need to deal with * them: the page table code is curly enough to need helper functions to keep * it clear and clean. * - * The first helper takes a virtual address, and says which entry in the top - * level page table deals with that address. Since each top level entry deals - * with 4M, this effectively divides by 4M. */ -static unsigned vaddr_to_pgd_index(unsigned long vaddr) -{ - return vaddr >> (PAGE_SHIFT + PTES_PER_PAGE_SHIFT); -} - -/* There are two functions which return pointers to the shadow (aka "real") + * There are two functions which return pointers to the shadow (aka "real") * page tables. * * spgd_addr() takes the virtual address and returns a pointer to the top-level * page directory entry 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 spgd_t *spgd_addr(struct lguest *lg, u32 i, unsigned long vaddr) +static pgd_t *spgd_addr(struct lguest *lg, u32 i, unsigned long vaddr) { - unsigned int index = vaddr_to_pgd_index(vaddr); + unsigned int index = pgd_index(vaddr); /* We kill any Guest trying to touch the Switcher addresses. */ if (index >= SWITCHER_PGD_INDEX) { @@ -95,28 +83,28 @@ static spgd_t *spgd_addr(struct lguest *lg, u32 i, unsigned long vaddr) /* This routine then takes the PGD entry given above, which contains the * address of the PTE page. It then returns a pointer to the PTE entry for the * given address. */ -static spte_t *spte_addr(struct lguest *lg, spgd_t spgd, unsigned long vaddr) +static pte_t *spte_addr(struct lguest *lg, pgd_t spgd, unsigned long vaddr) { - spte_t *page = __va(spgd.pfn << PAGE_SHIFT); + pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT); /* You should never call this if the PGD entry wasn't valid */ - BUG_ON(!(spgd.flags & _PAGE_PRESENT)); - return &page[(vaddr >> PAGE_SHIFT) % PTES_PER_PAGE]; + BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT)); + return &page[(vaddr >> PAGE_SHIFT) % PTRS_PER_PTE]; } /* 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) { - unsigned int index = vaddr >> (PAGE_SHIFT + PTES_PER_PAGE_SHIFT); - return lg->pgdirs[lg->pgdidx].cr3 + index * sizeof(gpgd_t); + unsigned int index = vaddr >> (PGDIR_SHIFT); + return lg->pgdirs[lg->pgdidx].cr3 + index * sizeof(pgd_t); } static unsigned long gpte_addr(struct lguest *lg, - gpgd_t gpgd, unsigned long vaddr) + pgd_t gpgd, unsigned long vaddr) { - unsigned long gpage = gpgd.pfn << PAGE_SHIFT; - BUG_ON(!(gpgd.flags & _PAGE_PRESENT)); - return gpage + ((vaddr>>PAGE_SHIFT) % PTES_PER_PAGE) * sizeof(gpte_t); + unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT; + BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT)); + return gpage + ((vaddr>>PAGE_SHIFT) % PTRS_PER_PTE) * sizeof(pte_t); } /*H:350 This routine takes a page number given by the Guest and converts it to @@ -149,16 +137,15 @@ 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 spte_t gpte_to_spte(struct lguest *lg, gpte_t gpte, int write) +static pte_t gpte_to_spte(struct lguest *lg, pte_t gpte, int write) { - spte_t spte; - unsigned long pfn, base; + unsigned long pfn, base, flags; /* The Guest sets the global flag, because it thinks that it is using * PGE. We only told it to use PGE so it would tell us whether it was * flushing a kernel mapping or a userspace mapping. We don't actually * use the global bit, so throw it away. */ - spte.flags = (gpte.flags & ~_PAGE_GLOBAL); + flags = (pte_flags(gpte) & ~_PAGE_GLOBAL); /* The Guest's pages are offset inside the Launcher. */ base = (unsigned long)lg->mem_base / PAGE_SIZE; @@ -167,38 +154,38 @@ static spte_t gpte_to_spte(struct lguest *lg, gpte_t gpte, int write) * get_pfn(), because it returns 0xFFFFFFFF on failure, which wouldn't * fit in spte.pfn. get_pfn() finds the real physical number of the * page, given the virtual number. */ - pfn = get_pfn(base + gpte.pfn, write); + pfn = get_pfn(base + pte_pfn(gpte), write); if (pfn == -1UL) { - kill_guest(lg, "failed to get page %u", gpte.pfn); + kill_guest(lg, "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! */ - spte.flags = 0; + flags = 0; } - /* Now we assign the page number, and our shadow PTE is complete. */ - spte.pfn = pfn; - return spte; + /* Now we assemble our shadow PTE from the page number and flags. */ + return pfn_pte(pfn, __pgprot(flags)); } /*H:460 And to complete the chain, release_pte() looks like this: */ -static void release_pte(spte_t pte) +static void release_pte(pte_t pte) { /* Remember that get_user_pages() took a reference to the page, in * get_pfn()? We have to put it back now. */ - if (pte.flags & _PAGE_PRESENT) - put_page(pfn_to_page(pte.pfn)); + if (pte_flags(pte) & _PAGE_PRESENT) + put_page(pfn_to_page(pte_pfn(pte))); } /*:*/ -static void check_gpte(struct lguest *lg, gpte_t gpte) +static void check_gpte(struct lguest *lg, pte_t gpte) { - if ((gpte.flags & (_PAGE_PWT|_PAGE_PSE)) || gpte.pfn >= lg->pfn_limit) + if ((pte_flags(gpte) & (_PAGE_PWT|_PAGE_PSE)) + || pte_pfn(gpte) >= lg->pfn_limit) kill_guest(lg, "bad page table entry"); } -static void check_gpgd(struct lguest *lg, gpgd_t gpgd) +static void check_gpgd(struct lguest *lg, pgd_t gpgd) { - if ((gpgd.flags & ~_PAGE_TABLE) || gpgd.pfn >= lg->pfn_limit) + if ((pgd_flags(gpgd) & ~_PAGE_TABLE) || pgd_pfn(gpgd) >= lg->pfn_limit) kill_guest(lg, "bad page directory entry"); } @@ -214,21 +201,21 @@ static void check_gpgd(struct lguest *lg, gpgd_t gpgd) * true. */ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode) { - gpgd_t gpgd; - spgd_t *spgd; + pgd_t gpgd; + pgd_t *spgd; unsigned long gpte_ptr; - gpte_t gpte; - spte_t *spte; + pte_t gpte; + pte_t *spte; /* First step: get the top-level Guest page table entry. */ - gpgd = mkgpgd(lgread_u32(lg, gpgd_addr(lg, vaddr))); + gpgd = __pgd(lgread_u32(lg, gpgd_addr(lg, vaddr))); /* Toplevel not present? We can't map it in. */ - if (!(gpgd.flags & _PAGE_PRESENT)) + if (!(pgd_flags(gpgd) & _PAGE_PRESENT)) return 0; /* Now look at the matching shadow entry. */ spgd = spgd_addr(lg, lg->pgdidx, vaddr); - if (!(spgd->flags & _PAGE_PRESENT)) { + 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 @@ -241,34 +228,35 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode) check_gpgd(lg, 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->raw.val = (__pa(ptepage) | gpgd.flags); + *spgd = __pgd(__pa(ptepage) | pgd_flags(gpgd)); } /* 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 = mkgpte(lgread_u32(lg, gpte_ptr)); + gpte = __pte(lgread_u32(lg, gpte_ptr)); /* If this page isn't in the Guest page tables, we can't page it in. */ - if (!(gpte.flags & _PAGE_PRESENT)) + if (!(pte_flags(gpte) & _PAGE_PRESENT)) return 0; /* Check they're not trying to write to a page the Guest wants * read-only (bit 2 of errcode == write). */ - if ((errcode & 2) && !(gpte.flags & _PAGE_RW)) + if ((errcode & 2) && !(pte_flags(gpte) & _PAGE_RW)) return 0; /* User access to a kernel page? (bit 3 == user access) */ - if ((errcode & 4) && !(gpte.flags & _PAGE_USER)) + if ((errcode & 4) && !(pte_flags(gpte) & _PAGE_USER)) return 0; /* 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); /* Add the _PAGE_ACCESSED and (for a write) _PAGE_DIRTY flag */ - gpte.flags |= _PAGE_ACCESSED; + gpte = pte_mkyoung(gpte); + if (errcode & 2) - gpte.flags |= _PAGE_DIRTY; + gpte = pte_mkdirty(gpte); /* Get the pointer to the shadow PTE entry we're going to set. */ spte = spte_addr(lg, *spgd, vaddr); @@ -278,21 +266,18 @@ 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 (gpte.flags & _PAGE_DIRTY) + if (pte_dirty(gpte)) *spte = gpte_to_spte(lg, gpte, 1); - else { + 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 come back here when a write does actually ocur, so we can * update the Guest's _PAGE_DIRTY flag. */ - gpte_t ro_gpte = gpte; - ro_gpte.flags &= ~_PAGE_RW; - *spte = gpte_to_spte(lg, ro_gpte, 0); - } + *spte = gpte_to_spte(lg, 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_u32(lg, gpte_ptr, gpte.raw.val); + lgwrite_u32(lg, gpte_ptr, pte_val(gpte)); /* We succeeded in mapping the page! */ return 1; @@ -308,17 +293,18 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode) * mapped by the shadow page tables, and is it writable? */ static int page_writable(struct lguest *lg, unsigned long vaddr) { - spgd_t *spgd; + pgd_t *spgd; unsigned long flags; /* Look at the top level entry: is it present? */ spgd = spgd_addr(lg, lg->pgdidx, vaddr); - if (!(spgd->flags & _PAGE_PRESENT)) + if (!(pgd_flags(*spgd) & _PAGE_PRESENT)) return 0; /* Check the flags on the pte entry itself: it must be present and * writable. */ - flags = spte_addr(lg, *spgd, vaddr)->flags; + flags = pte_flags(*(spte_addr(lg, *spgd, vaddr))); + return (flags & (_PAGE_PRESENT|_PAGE_RW)) == (_PAGE_PRESENT|_PAGE_RW); } @@ -332,22 +318,22 @@ void pin_page(struct lguest *lg, unsigned long vaddr) } /*H:450 If we chase down the release_pgd() code, it looks like this: */ -static void release_pgd(struct lguest *lg, spgd_t *spgd) +static void release_pgd(struct lguest *lg, pgd_t *spgd) { /* If the entry's not present, there's nothing to release. */ - if (spgd->flags & _PAGE_PRESENT) { + if (pgd_flags(*spgd) & _PAGE_PRESENT) { unsigned int i; /* Converting the pfn to find the actual PTE page is easy: turn * the page number into a physical address, then convert to a * virtual address (easy for kernel pages like this one). */ - spte_t *ptepage = __va(spgd->pfn << PAGE_SHIFT); + pte_t *ptepage = __va(pgd_pfn(*spgd) << PAGE_SHIFT); /* For each entry in the page, we might need to release it. */ - for (i = 0; i < PTES_PER_PAGE; i++) + for (i = 0; i < PTRS_PER_PTE; i++) release_pte(ptepage[i]); /* Now we can free the page of PTEs */ free_page((long)ptepage); /* And zero out the PGD entry we we never release it twice. */ - spgd->raw.val = 0; + *spgd = __pgd(0); } } @@ -359,7 +345,7 @@ static void flush_user_mappings(struct lguest *lg, int idx) { unsigned int i; /* Release every pgd entry up to the kernel's address. */ - for (i = 0; i < vaddr_to_pgd_index(lg->page_offset); i++) + for (i = 0; i < pgd_index(lg->page_offset); i++) release_pgd(lg, lg->pgdirs[idx].pgdir + i); } @@ -398,7 +384,7 @@ static unsigned int new_pgdir(struct lguest *lg, next = random32() % ARRAY_SIZE(lg->pgdirs); /* If it's never been allocated at all before, try now. */ if (!lg->pgdirs[next].pgdir) { - lg->pgdirs[next].pgdir = (spgd_t *)get_zeroed_page(GFP_KERNEL); + 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; @@ -475,26 +461,27 @@ void guest_pagetable_clear_all(struct lguest *lg) * they set _PAGE_DIRTY then we can put a writable PTE entry in immediately. */ static void do_set_pte(struct lguest *lg, int idx, - unsigned long vaddr, gpte_t gpte) + unsigned long vaddr, pte_t gpte) { /* Look up the matching shadow page directot entry. */ - spgd_t *spgd = spgd_addr(lg, idx, vaddr); + pgd_t *spgd = spgd_addr(lg, idx, vaddr); /* If the top level isn't present, there's no entry to update. */ - if (spgd->flags & _PAGE_PRESENT) { + if (pgd_flags(*spgd) & _PAGE_PRESENT) { /* Otherwise, we start by releasing the existing entry. */ - spte_t *spte = spte_addr(lg, *spgd, vaddr); + pte_t *spte = spte_addr(lg, *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 (gpte.flags & (_PAGE_DIRTY | _PAGE_ACCESSED)) { + if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) { check_gpte(lg, gpte); - *spte = gpte_to_spte(lg, gpte, gpte.flags&_PAGE_DIRTY); + *spte = gpte_to_spte(lg, gpte, + pte_flags(gpte) & _PAGE_DIRTY); } else /* Otherwise we can demand_page() it in later. */ - spte->raw.val = 0; + *spte = __pte(0); } } @@ -509,7 +496,7 @@ 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, - unsigned long cr3, unsigned long vaddr, gpte_t gpte) + unsigned long cr3, unsigned long vaddr, pte_t gpte) { /* Kernel mappings must be changed on all top levels. Slow, but * doesn't happen often. */ @@ -564,15 +551,15 @@ void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 idx) int init_guest_pagetable(struct lguest *lg, unsigned long pgtable) { /* In flush_user_mappings() we loop from 0 to - * "vaddr_to_pgd_index(lg->page_offset)". This assumes it won't hit + * "pgd_index(lg->page_offset)". This assumes it won't hit * the Switcher mappings, so check that now. */ - if (vaddr_to_pgd_index(lg->page_offset) >= SWITCHER_PGD_INDEX) + if (pgd_index(lg->page_offset) >= SWITCHER_PGD_INDEX) return -EINVAL; /* We start on the first shadow page table, and give it a blank PGD * page. */ lg->pgdidx = 0; lg->pgdirs[lg->pgdidx].cr3 = pgtable; - lg->pgdirs[lg->pgdidx].pgdir = (spgd_t*)get_zeroed_page(GFP_KERNEL); + lg->pgdirs[lg->pgdidx].pgdir = (pgd_t*)get_zeroed_page(GFP_KERNEL); if (!lg->pgdirs[lg->pgdidx].pgdir) return -ENOMEM; return 0; @@ -597,14 +584,14 @@ void free_guest_pagetable(struct lguest *lg) * for each CPU already set up, we just need to hook them in. */ void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages) { - spte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages); - spgd_t switcher_pgd; - spte_t regs_pte; + pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages); + pgd_t switcher_pgd; + pte_t regs_pte; /* Make the last PGD entry for this Guest point to the Switcher's PTE * page for this CPU (with appropriate flags). */ - switcher_pgd.pfn = __pa(switcher_pte_page) >> PAGE_SHIFT; - switcher_pgd.flags = _PAGE_KERNEL; + switcher_pgd = __pgd(__pa(switcher_pte_page) | _PAGE_KERNEL); + lg->pgdirs[lg->pgdidx].pgdir[SWITCHER_PGD_INDEX] = switcher_pgd; /* We also change the Switcher PTE page. When we're running the Guest, @@ -614,10 +601,8 @@ 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 = __pa(lg->regs_page) >> PAGE_SHIFT; - regs_pte.flags = _PAGE_KERNEL; - switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTES_PER_PAGE] - = regs_pte; + regs_pte = pfn_pte (__pa(lg->regs_page) >> PAGE_SHIFT, __pgprot(_PAGE_KERNEL)); + switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTRS_PER_PTE] = regs_pte; } /*:*/ @@ -638,24 +623,25 @@ static __init void populate_switcher_pte_page(unsigned int cpu, unsigned int pages) { unsigned int i; - spte_t *pte = switcher_pte_page(cpu); + pte_t *pte = switcher_pte_page(cpu); /* The first entries are easy: they map the Switcher code. */ for (i = 0; i < pages; i++) { - pte[i].pfn = page_to_pfn(switcher_page[i]); - pte[i].flags = _PAGE_PRESENT|_PAGE_ACCESSED; + pte[i] = mk_pte(switcher_page[i], + __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)); } /* The only other thing we map is this CPU's pair of pages. */ i = pages + cpu*2; /* First page (Guest registers) is writable from the Guest */ - pte[i].pfn = page_to_pfn(switcher_page[i]); - pte[i].flags = _PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW; + pte[i] = pfn_pte(page_to_pfn(switcher_page[i]), + __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW)); + /* The second page contains the "struct lguest_ro_state", and is * read-only. */ - pte[i+1].pfn = page_to_pfn(switcher_page[i+1]); - pte[i+1].flags = _PAGE_PRESENT|_PAGE_ACCESSED; + pte[i+1] = pfn_pte(page_to_pfn(switcher_page[i+1]), + __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)); } /*H:510 At boot or module load time, init_pagetables() allocates and populates @@ -665,7 +651,7 @@ __init int init_pagetables(struct page **switcher_page, unsigned int pages) unsigned int i; for_each_possible_cpu(i) { - switcher_pte_page(i) = (spte_t *)get_zeroed_page(GFP_KERNEL); + switcher_pte_page(i) = (pte_t *)get_zeroed_page(GFP_KERNEL); if (!switcher_pte_page(i)) { free_switcher_pte_pages(); return -ENOMEM; |