lguest: add MMIO region allocator in example launcher.
This is where we point our PCI BARs, so that we can intercept MMIO
accesses. We tell the kernel about it so any faults in this area are
directed to us.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index 02f3539..35d7aa9 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -92,7 +92,7 @@
/* The pointer to the start of guest memory. */
static void *guest_base;
/* The maximum guest physical address allowed, and maximum possible. */
-static unsigned long guest_limit, guest_max;
+static unsigned long guest_limit, guest_max, guest_mmio;
/* The /dev/lguest file descriptor. */
static int lguest_fd;
@@ -321,6 +321,23 @@
return addr;
}
+/* Get some bytes which won't be mapped into the guest. */
+static unsigned long get_mmio_region(size_t size)
+{
+ unsigned long addr = guest_mmio;
+ size_t i;
+
+ if (!size)
+ return addr;
+
+ /* Size has to be a power of 2 (and multiple of 16) */
+ for (i = 1; i < size; i <<= 1);
+
+ guest_mmio += i;
+
+ return addr;
+}
+
/*
* This routine is used to load the kernel or initrd. It tries mmap, but if
* that fails (Plan 9's kernel file isn't nicely aligned on page boundaries),
@@ -549,9 +566,10 @@
unsigned long args[] = { LHREQ_INITIALIZE,
(unsigned long)guest_base,
guest_limit / getpagesize(), start,
- guest_limit / getpagesize() };
- verbose("Guest: %p - %p (%#lx)\n",
- guest_base, guest_base + guest_limit, guest_limit);
+ (guest_mmio+getpagesize()-1) / getpagesize() };
+ verbose("Guest: %p - %p (%#lx, MMIO %#lx)\n",
+ guest_base, guest_base + guest_limit,
+ guest_limit, guest_mmio);
lguest_fd = open_or_die("/dev/lguest", O_RDWR);
if (write(lguest_fd, args, sizeof(args)) < 0)
err(1, "Writing to /dev/lguest");
@@ -2079,7 +2097,7 @@
guest_base = map_zeroed_pages(mem / getpagesize()
+ DEVICE_PAGES);
guest_limit = mem;
- guest_max = mem + DEVICE_PAGES*getpagesize();
+ guest_max = guest_mmio = mem + DEVICE_PAGES*getpagesize();
devices.descpage = get_pages(1);
break;
}