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| author | Rusty Russell <rusty@rustcorp.com.au> | 2013-04-22 08:40:42 +0400 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2013-04-22 10:15:03 +0400 |
| commit | 6b39271746de131366a14bcf04f5740cdc4abdef (patch) | |
| tree | a2f8875e7186df5a801345a61b01b9b2eab9bbca | |
| parent | 6d0cda93c0d3c8bb0a553047c10f114c88c8af89 (diff) | |
| download | linux-6b39271746de131366a14bcf04f5740cdc4abdef.tar.xz | |
lguest: map Switcher below fixmap.
Now we've adjusted all the code, we can simply set switcher_addr to
wherever it needs to go below the fixmaps, rather than asserting that
it should be so.
With large NR_CPUS and PAE, people were hitting the "mapping switcher
would thwack fixmap" message.
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| -rw-r--r-- | arch/x86/include/asm/lguest.h | 6 | ||||
| -rw-r--r-- | drivers/lguest/core.c | 15 |
2 files changed, 5 insertions, 16 deletions
diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h index 74edebd010ab..e2d4a4afa8c3 100644 --- a/arch/x86/include/asm/lguest.h +++ b/arch/x86/include/asm/lguest.h @@ -14,12 +14,6 @@ /* Page for Switcher text itself, then two pages per cpu */ #define TOTAL_SWITCHER_PAGES (1 + 2 * nr_cpu_ids) -/* We map at -4M (-2M for PAE) for ease of mapping (one PTE page). */ -#ifdef CONFIG_X86_PAE -#define SWITCHER_ADDR 0xFFE00000 -#else -#define SWITCHER_ADDR 0xFFC00000 -#endif /* Where we map the Switcher, in both Host and Guest. */ extern unsigned long switcher_addr; diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index 7e1d7ee36478..0bf1e4edf04d 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -83,18 +83,13 @@ static __init int map_switcher(void) } } - switcher_addr = SWITCHER_ADDR; - /* - * First we check that the Switcher won't overlap the fixmap area at - * the top of memory. It's currently nowhere near, but it could have - * very strange effects if it ever happened. + * We place the Switcher underneath the fixmap area, which is the + * highest virtual address we can get. This is important, since we + * tell the Guest it can't access this memory, so we want its ceiling + * as high as possible. */ - if (switcher_addr + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){ - err = -ENOMEM; - printk("lguest: mapping switcher would thwack fixmap\n"); - goto free_pages; - } + switcher_addr = FIXADDR_START - (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE; /* * Now we reserve the "virtual memory area" we want. We might |