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authorMatias Zabaljauregui <zabaljauregui@gmail.com>2008-09-29 00:40:07 -0400
committerRusty Russell <rusty@rustcorp.com.au>2008-12-29 17:56:11 -0500
commit58a24566449892dda409b9ad92c2e56c76c5670c (patch)
tree4dfe2305dfd078c71d949ea8cc6c9cc6e2679494 /Documentation
parentbe3c5832d51174ef7f21cefd6ad612dabdcb62fd (diff)
lguest: move the initial guest page table creation code to the host
This patch moves the initial guest page table creation code to the host, so the launcher keeps working with PAE enabled configs. Signed-off-by: Matias Zabaljauregui <zabaljauregui@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/lguest/lguest.c60
1 files changed, 6 insertions, 54 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index aa2574ca94c7..f2dbbf3bdeab 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -481,51 +481,6 @@ static unsigned long load_initrd(const char *name, unsigned long mem)
481 /* We return the initrd size. */ 481 /* We return the initrd size. */
482 return len; 482 return len;
483} 483}
484
485/* Once we know how much memory we have we can construct simple linear page
486 * tables which set virtual == physical which will get the Guest far enough
487 * into the boot to create its own.
488 *
489 * We lay them out of the way, just below the initrd (which is why we need to
490 * know its size here). */
491static unsigned long setup_pagetables(unsigned long mem,
492 unsigned long initrd_size)
493{
494 unsigned long *pgdir, *linear;
495 unsigned int mapped_pages, i, linear_pages;
496 unsigned int ptes_per_page = getpagesize()/sizeof(void *);
497
498 mapped_pages = mem/getpagesize();
499
500 /* Each PTE page can map ptes_per_page pages: how many do we need? */
501 linear_pages = (mapped_pages + ptes_per_page-1)/ptes_per_page;
502
503 /* We put the toplevel page directory page at the top of memory. */
504 pgdir = from_guest_phys(mem) - initrd_size - getpagesize();
505
506 /* Now we use the next linear_pages pages as pte pages */
507 linear = (void *)pgdir - linear_pages*getpagesize();
508
509 /* Linear mapping is easy: put every page's address into the mapping in
510 * order. PAGE_PRESENT contains the flags Present, Writable and
511 * Executable. */
512 for (i = 0; i < mapped_pages; i++)
513 linear[i] = ((i * getpagesize()) | PAGE_PRESENT);
514
515 /* The top level points to the linear page table pages above. */
516 for (i = 0; i < mapped_pages; i += ptes_per_page) {
517 pgdir[i/ptes_per_page]
518 = ((to_guest_phys(linear) + i*sizeof(void *))
519 | PAGE_PRESENT);
520 }
521
522 verbose("Linear mapping of %u pages in %u pte pages at %#lx\n",
523 mapped_pages, linear_pages, to_guest_phys(linear));
524
525 /* We return the top level (guest-physical) address: the kernel needs
526 * to know where it is. */
527 return to_guest_phys(pgdir);
528}
529/*:*/ 484/*:*/
530 485
531/* Simple routine to roll all the commandline arguments together with spaces 486/* Simple routine to roll all the commandline arguments together with spaces
@@ -548,13 +503,13 @@ static void concat(char *dst, char *args[])
548 503
549/*L:185 This is where we actually tell the kernel to initialize the Guest. We 504/*L:185 This is where we actually tell the kernel to initialize the Guest. We
550 * saw the arguments it expects when we looked at initialize() in lguest_user.c: 505 * saw the arguments it expects when we looked at initialize() in lguest_user.c:
551 * the base of Guest "physical" memory, the top physical page to allow, the 506 * the base of Guest "physical" memory, the top physical page to allow and the
552 * top level pagetable and the entry point for the Guest. */ 507 * entry point for the Guest. */
553static int tell_kernel(unsigned long pgdir, unsigned long start) 508static int tell_kernel(unsigned long start)
554{ 509{
555 unsigned long args[] = { LHREQ_INITIALIZE, 510 unsigned long args[] = { LHREQ_INITIALIZE,
556 (unsigned long)guest_base, 511 (unsigned long)guest_base,
557 guest_limit / getpagesize(), pgdir, start }; 512 guest_limit / getpagesize(), start };
558 int fd; 513 int fd;
559 514
560 verbose("Guest: %p - %p (%#lx)\n", 515 verbose("Guest: %p - %p (%#lx)\n",
@@ -1941,7 +1896,7 @@ int main(int argc, char *argv[])
1941{ 1896{
1942 /* Memory, top-level pagetable, code startpoint and size of the 1897 /* Memory, top-level pagetable, code startpoint and size of the
1943 * (optional) initrd. */ 1898 * (optional) initrd. */
1944 unsigned long mem = 0, pgdir, start, initrd_size = 0; 1899 unsigned long mem = 0, start, initrd_size = 0;
1945 /* Two temporaries and the /dev/lguest file descriptor. */ 1900 /* Two temporaries and the /dev/lguest file descriptor. */
1946 int i, c, lguest_fd; 1901 int i, c, lguest_fd;
1947 /* The boot information for the Guest. */ 1902 /* The boot information for the Guest. */
@@ -2040,9 +1995,6 @@ int main(int argc, char *argv[])
2040 boot->hdr.type_of_loader = 0xFF; 1995 boot->hdr.type_of_loader = 0xFF;
2041 } 1996 }
2042 1997
2043 /* Set up the initial linear pagetables, starting below the initrd. */
2044 pgdir = setup_pagetables(mem, initrd_size);
2045
2046 /* The Linux boot header contains an "E820" memory map: ours is a 1998 /* The Linux boot header contains an "E820" memory map: ours is a
2047 * simple, single region. */ 1999 * simple, single region. */
2048 boot->e820_entries = 1; 2000 boot->e820_entries = 1;
@@ -2064,7 +2016,7 @@ int main(int argc, char *argv[])
2064 2016
2065 /* We tell the kernel to initialize the Guest: this returns the open 2017 /* We tell the kernel to initialize the Guest: this returns the open
2066 * /dev/lguest file descriptor. */ 2018 * /dev/lguest file descriptor. */
2067 lguest_fd = tell_kernel(pgdir, start); 2019 lguest_fd = tell_kernel(start);
2068 2020
2069 /* We clone off a thread, which wakes the Launcher whenever one of the 2021 /* We clone off a thread, which wakes the Launcher whenever one of the
2070 * input file descriptors needs attention. We call this the Waker, and 2022 * input file descriptors needs attention. We call this the Waker, and