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authorRusty Russell <rusty@rustcorp.com.au>2007-10-22 05:03:36 +0400
committerRusty Russell <rusty@rustcorp.com.au>2007-10-23 09:49:54 +0400
commit47436aa4ad054c1c7c8231618e86ebd9305308dc (patch)
treea9ba6e0521f9116442144a86e781a3164ec86094 /drivers/lguest/lguest_user.c
parentc18acd73ffc209def08003a1927473096f66c5ad (diff)
downloadlinux-47436aa4ad054c1c7c8231618e86ebd9305308dc.tar.xz
Boot with virtual == physical to get closer to native Linux.
1) This allows us to get alot closer to booting bzImages. 2) It means we don't have to know page_offset. 3) The Guest needs to modify the boot pagetables to create the PAGE_OFFSET mapping before jumping to C code. 4) guest_pa() walks the page tables rather than using page_offset. 5) We don't use page_offset to figure out whether to emulate: it was always kinda quesationable, and won't work for instructions done before remapping (bzImage unpacking in particular). 6) We still want the kernel address for tlb flushing: have the initial hypercall give us that, too. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/lguest/lguest_user.c')
-rw-r--r--drivers/lguest/lguest_user.c11
1 files changed, 2 insertions, 9 deletions
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index b184652e45d7..61b177e1e649 100644
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -111,7 +111,7 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o)
return run_guest(lg, (unsigned long __user *)user);
}
-/*L:020 The initialization write supplies 5 pointer sized (32 or 64 bit)
+/*L:020 The initialization write supplies 4 pointer sized (32 or 64 bit)
* values (in addition to the LHREQ_INITIALIZE value). These are:
*
* base: The start of the Guest-physical memory inside the Launcher memory.
@@ -124,12 +124,6 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o)
* pagetables (which are set up by the Launcher).
*
* start: The first instruction to execute ("eip" in x86-speak).
- *
- * page_offset: The PAGE_OFFSET constant in the Guest kernel. We should
- * probably wean the code off this, but it's a very useful constant! Any
- * address above this is within the Guest kernel, and any kernel address can
- * quickly converted from physical to virtual by adding PAGE_OFFSET. It's
- * 0xC0000000 (3G) by default, but it's configurable at kernel build time.
*/
static int initialize(struct file *file, const unsigned long __user *input)
{
@@ -137,7 +131,7 @@ static int initialize(struct file *file, const unsigned long __user *input)
* Guest. */
struct lguest *lg;
int err;
- unsigned long args[5];
+ unsigned long args[4];
/* We grab the Big Lguest lock, which protects against multiple
* simultaneous initializations. */
@@ -162,7 +156,6 @@ static int initialize(struct file *file, const unsigned long __user *input)
/* Populate the easy fields of our "struct lguest" */
lg->mem_base = (void __user *)(long)args[0];
lg->pfn_limit = args[1];
- lg->page_offset = args[4];
/* We need a complete page for the Guest registers: they are accessible
* to the Guest and we can only grant it access to whole pages. */