x86, documentation: kernel-parameters replace X86-32,X86-64 with X86

[safe/jmp/linux-2.6] / Documentation / lguest / lguest.c

diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index aa2574c..d36fcc0 100644 (file)
--- 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)
        /* We return the initrd size. */
        return len;
 }
-
-/* Once we know how much memory we have we can construct simple linear page
- * tables which set virtual == physical which will get the Guest far enough
- * into the boot to create its own.
- *
- * We lay them out of the way, just below the initrd (which is why we need to
- * know its size here). */
-static unsigned long setup_pagetables(unsigned long mem,
-                                     unsigned long initrd_size)
-{
-       unsigned long *pgdir, *linear;
-       unsigned int mapped_pages, i, linear_pages;
-       unsigned int ptes_per_page = getpagesize()/sizeof(void *);
-
-       mapped_pages = mem/getpagesize();
-
-       /* Each PTE page can map ptes_per_page pages: how many do we need? */
-       linear_pages = (mapped_pages + ptes_per_page-1)/ptes_per_page;
-
-       /* We put the toplevel page directory page at the top of memory. */
-       pgdir = from_guest_phys(mem) - initrd_size - getpagesize();
-
-       /* Now we use the next linear_pages pages as pte pages */
-       linear = (void *)pgdir - linear_pages*getpagesize();
-
-       /* Linear mapping is easy: put every page's address into the mapping in
-        * order.  PAGE_PRESENT contains the flags Present, Writable and
-        * Executable. */
-       for (i = 0; i < mapped_pages; i++)
-               linear[i] = ((i * getpagesize()) | PAGE_PRESENT);
-
-       /* The top level points to the linear page table pages above. */
-       for (i = 0; i < mapped_pages; i += ptes_per_page) {
-               pgdir[i/ptes_per_page]
-                       = ((to_guest_phys(linear) + i*sizeof(void *))
-                          | PAGE_PRESENT);
-       }
-
-       verbose("Linear mapping of %u pages in %u pte pages at %#lx\n",
-               mapped_pages, linear_pages, to_guest_phys(linear));
-
-       /* We return the top level (guest-physical) address: the kernel needs
-        * to know where it is. */
-       return to_guest_phys(pgdir);
-}
 /*:*/
 
 /* Simple routine to roll all the commandline arguments together with spaces
@@ -548,13 +503,13 @@ static void concat(char *dst, char *args[])
 
 /*L:185 This is where we actually tell the kernel to initialize the Guest.  We
  * saw the arguments it expects when we looked at initialize() in lguest_user.c:
- * the base of Guest "physical" memory, the top physical page to allow, the
- * top level pagetable and the entry point for the Guest. */
-static int tell_kernel(unsigned long pgdir, unsigned long start)
+ * the base of Guest "physical" memory, the top physical page to allow and the
+ * entry point for the Guest. */
+static int tell_kernel(unsigned long start)
 {
        unsigned long args[] = { LHREQ_INITIALIZE,
                                 (unsigned long)guest_base,
-                                guest_limit / getpagesize(), pgdir, start };
+                                guest_limit / getpagesize(), start };
        int fd;
 
        verbose("Guest: %p - %p (%#lx)\n",
@@ -1675,6 +1630,13 @@ static bool service_io(struct device *dev)
                }
        }
 
+       /* OK, so we noted that it was pretty poor to use an fdatasync as a
+        * barrier.  But Christoph Hellwig points out that we need a sync
+        * *afterwards* as well: "Barriers specify no reordering to the front
+        * or the back."  And Jens Axboe confirmed it, so here we are: */
+       if (out->type & VIRTIO_BLK_T_BARRIER)
+               fdatasync(vblk->fd);
+
        /* We can't trigger an IRQ, because we're not the Launcher.  It does
         * that when we tell it we're done. */
        add_used(dev->vq, head, wlen);
@@ -1941,7 +1903,7 @@ int main(int argc, char *argv[])
 {
        /* Memory, top-level pagetable, code startpoint and size of the
         * (optional) initrd. */
-       unsigned long mem = 0, pgdir, start, initrd_size = 0;
+       unsigned long mem = 0, start, initrd_size = 0;
        /* Two temporaries and the /dev/lguest file descriptor. */
        int i, c, lguest_fd;
        /* The boot information for the Guest. */
@@ -2040,9 +2002,6 @@ int main(int argc, char *argv[])
                boot->hdr.type_of_loader = 0xFF;
        }
 
-       /* Set up the initial linear pagetables, starting below the initrd. */
-       pgdir = setup_pagetables(mem, initrd_size);
-
        /* The Linux boot header contains an "E820" memory map: ours is a
         * simple, single region. */
        boot->e820_entries = 1;
@@ -2064,7 +2023,7 @@ int main(int argc, char *argv[])
 
        /* We tell the kernel to initialize the Guest: this returns the open
         * /dev/lguest file descriptor. */
-       lguest_fd = tell_kernel(pgdir, start);
+       lguest_fd = tell_kernel(start);
 
        /* We clone off a thread, which wakes the Launcher whenever one of the
         * input file descriptors needs attention.  We call this the Waker, and