diff options
| author | Rusty Russell | 2007-10-22 11:03:26 +1000 |
|---|---|---|
| committer | Rusty Russell | 2007-10-23 15:49:50 +1000 |
| commit | 3c6b5bfa3cf3b4057788e08482a468cc3bc00780 (patch) | |
| tree | f0d67890f6f8c9d0840c9b19a483ec06cbf822ef /drivers/lguest/page_tables.c | |
| parent | 6649bb7af6a819b675bfcf22ab704737e905645a (diff) | |
Introduce guest mem offset, static link example launcher
In order to avoid problematic special linking of the Launcher, we give
the Host an offset: this means we can use any memory region in the
Launcher as Guest memory rather than insisting on mmap() at 0.
The result is quite pleasing: a number of casts are replaced with
simple additions.
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 | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index b7a924ace684..9cd2faceb87c 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -152,7 +152,7 @@ static unsigned long get_pfn(unsigned long virtpfn, int write) static spte_t gpte_to_spte(struct lguest *lg, gpte_t gpte, int write) { spte_t spte; - unsigned long pfn; + unsigned long pfn, base; /* 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 @@ -160,11 +160,14 @@ static spte_t gpte_to_spte(struct lguest *lg, gpte_t gpte, int write) * use the global bit, so throw it away. */ spte.flags = (gpte.flags & ~_PAGE_GLOBAL); + /* The Guest's pages are offset inside the Launcher. */ + base = (unsigned long)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 * fit in spte.pfn. get_pfn() finds the real physical number of the * page, given the virtual number. */ - pfn = get_pfn(gpte.pfn, write); + pfn = get_pfn(base + gpte.pfn, write); if (pfn == -1UL) { kill_guest(lg, "failed to get page %u", gpte.pfn); /* When we destroy the Guest, we'll go through the shadow page |