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lguest: prepare to make SWITCHER_ADDR a variable.
We currently use the whole top PGD entry for the switcher, but that's hitting the fixmap in some configurations (mainly, large NR_CPUS). Introduce a variable, currently set to the constant. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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parent
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commit
406a590ba1
3 changed files with 14 additions and 10 deletions
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@ -23,6 +23,8 @@
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#else
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#define SWITCHER_ADDR 0xFFC00000
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#endif
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/* Where we map the Switcher, in both Host and Guest. */
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extern unsigned long switcher_addr;
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/* Found in switcher.S */
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extern unsigned long default_idt_entries[];
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@ -20,7 +20,7 @@
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#include <asm/asm-offsets.h>
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#include "lg.h"
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unsigned long switcher_addr;
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static struct vm_struct *switcher_vma;
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static struct page **switcher_page;
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@ -75,25 +75,27 @@ static __init int map_switcher(void)
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}
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}
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switcher_addr = SWITCHER_ADDR;
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/*
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* First we check that the Switcher won't overlap the fixmap area at
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* the top of memory. It's currently nowhere near, but it could have
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* very strange effects if it ever happened.
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*/
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if (SWITCHER_ADDR + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){
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if (switcher_addr + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){
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err = -ENOMEM;
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printk("lguest: mapping switcher would thwack fixmap\n");
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goto free_pages;
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}
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/*
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* Now we reserve the "virtual memory area" we want: 0xFFC00000
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* (SWITCHER_ADDR). We might not get it in theory, but in practice
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* it's worked so far. The end address needs +1 because __get_vm_area
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* allocates an extra guard page, so we need space for that.
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* Now we reserve the "virtual memory area" we want. We might
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* not get it in theory, but in practice it's worked so far.
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* The end address needs +1 because __get_vm_area allocates an
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* extra guard page, so we need space for that.
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*/
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switcher_vma = __get_vm_area(TOTAL_SWITCHER_PAGES * PAGE_SIZE,
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VM_ALLOC, SWITCHER_ADDR, SWITCHER_ADDR
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VM_ALLOC, switcher_addr, switcher_addr
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+ (TOTAL_SWITCHER_PAGES+1) * PAGE_SIZE);
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if (!switcher_vma) {
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err = -ENOMEM;
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@ -103,7 +105,7 @@ static __init int map_switcher(void)
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/*
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* This code actually sets up the pages we've allocated to appear at
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* SWITCHER_ADDR. map_vm_area() takes the vma we allocated above, the
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* switcher_addr. map_vm_area() takes the vma we allocated above, the
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* kind of pages we're mapping (kernel pages), and a pointer to our
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* array of struct pages. It increments that pointer, but we don't
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* care.
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@ -59,14 +59,14 @@ static struct {
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/* Offset from where switcher.S was compiled to where we've copied it */
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static unsigned long switcher_offset(void)
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{
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return SWITCHER_ADDR - (unsigned long)start_switcher_text;
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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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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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(switcher_addr + SHARED_SWITCHER_PAGES*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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