lguest: assume Switcher text is a single page.
ie. SHARED_SWITCHER_PAGES == 1. It is well under a page, and it's a minor simplification: it's nice to have *one* simplification in a patch series! Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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parent
856c608827
commit
93a2cdff98
5 changed files with 21 additions and 23 deletions
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@ -11,11 +11,8 @@
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#define GUEST_PL 1
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/* Every guest maps the core switcher code. */
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#define SHARED_SWITCHER_PAGES \
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DIV_ROUND_UP(end_switcher_text - start_switcher_text, PAGE_SIZE)
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/* Pages for switcher itself, then two pages per cpu */
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#define TOTAL_SWITCHER_PAGES (SHARED_SWITCHER_PAGES + 2 * nr_cpu_ids)
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/* Page for Switcher text itself, then two pages per cpu */
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#define TOTAL_SWITCHER_PAGES (1 + 2 * nr_cpu_ids)
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/* We map at -4M (-2M for PAE) for ease of mapping (one PTE page). */
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#ifdef CONFIG_X86_PAE
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@ -52,6 +52,13 @@ static __init int map_switcher(void)
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* easy.
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*/
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/* We assume Switcher text fits into a single page. */
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if (end_switcher_text - start_switcher_text > PAGE_SIZE) {
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printk(KERN_ERR "lguest: switcher text too large (%zu)\n",
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end_switcher_text - start_switcher_text);
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return -EINVAL;
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}
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/*
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* We allocate an array of struct page pointers. map_vm_area() wants
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* this, rather than just an array of pages.
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@ -326,7 +333,7 @@ static int __init init(void)
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goto out;
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/* Now we set up the pagetable implementation for the Guests. */
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err = init_pagetables(switcher_pages, SHARED_SWITCHER_PAGES);
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err = init_pagetables(switcher_pages);
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if (err)
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goto unmap;
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@ -15,7 +15,7 @@
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#include <asm/lguest.h>
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void free_pagetables(void);
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int init_pagetables(struct page **switcher_pages, unsigned int pages);
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int init_pagetables(struct page **switcher_pages);
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struct pgdir {
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unsigned long gpgdir;
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@ -1079,25 +1079,20 @@ static void free_switcher_pte_pages(void)
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/*H:520
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* Setting up the Switcher PTE page for given CPU is fairly easy, given
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* the CPU number and the "struct page"s for the Switcher code itself.
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*
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* Currently the Switcher is less than a page long, so "pages" is always 1.
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* the CPU number and the "struct page"s for the Switcher and per-cpu pages.
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*/
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static __init void populate_switcher_pte_page(unsigned int cpu,
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struct page *switcher_pages[],
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unsigned int pages)
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struct page *switcher_pages[])
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{
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unsigned int i;
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pte_t *pte = switcher_pte_page(cpu);
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int i;
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/* The first entries are easy: they map the Switcher code. */
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for (i = 0; i < pages; i++) {
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set_pte(&pte[i], mk_pte(switcher_pages[i],
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/* The first entries maps the Switcher code. */
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set_pte(&pte[0], mk_pte(switcher_pages[0],
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__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)));
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}
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/* The only other thing we map is this CPU's pair of pages. */
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i = pages + cpu*2;
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i = 1 + cpu*2;
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/* First page (Guest registers) is writable from the Guest */
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set_pte(&pte[i], pfn_pte(page_to_pfn(switcher_pages[i]),
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@ -1128,7 +1123,7 @@ static __init void populate_switcher_pte_page(unsigned int cpu,
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* At boot or module load time, init_pagetables() allocates and populates
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* the Switcher PTE page for each CPU.
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*/
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__init int init_pagetables(struct page **switcher_pages, unsigned int pages)
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__init int init_pagetables(struct page **switcher_pages)
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{
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unsigned int i;
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@ -1138,7 +1133,7 @@ __init int init_pagetables(struct page **switcher_pages, unsigned int pages)
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free_switcher_pte_pages();
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return -ENOMEM;
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}
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populate_switcher_pte_page(i, switcher_pages, pages);
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populate_switcher_pte_page(i, switcher_pages);
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}
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return 0;
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}
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@ -62,11 +62,10 @@ static unsigned long switcher_offset(void)
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return switcher_addr - (unsigned long)start_switcher_text;
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}
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/* This cpu's struct lguest_pages. */
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/* This cpu's struct lguest_pages (after the Switcher text page) */
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static struct lguest_pages *lguest_pages(unsigned int cpu)
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{
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return &(((struct lguest_pages *)
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(switcher_addr + SHARED_SWITCHER_PAGES*PAGE_SIZE))[cpu]);
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return &(((struct lguest_pages *)(switcher_addr + PAGE_SIZE))[cpu]);
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}
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static DEFINE_PER_CPU(struct lg_cpu *, lg_last_cpu);
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