multiboot header has 0 in mem_upper field

[Peter Chubb]

When booting a multiboot image,. mem_upper is now always zero.

To test, build qemu from current git head, then do
  cd tests/multiboot
  ./run_test.sh

You will see the test fail. In each case mem_upper is 0k.

git-bisect says the bad commit is 0169c511554cb0014a00290b0d3d26c31a49818f in qemu.git

[Peter Chubb (peter-chubb-1)]

This change fixes it.

diff --git a/exec.c b/exec.c
index 2435d9e..b387d28 100644
--- a/exec.c
+++ b/exec.c
@@ -1070,7 +1070,7 @@ static void *file_ram_alloc(RAMBlock *block,
         }

         /* MAP_POPULATE silently ignores failures */
- for (i = 0; i < (memory/hpagesize); i++) {
+ for (i = 0; i < (memory/hpagesize)-1; i++) {
             memset(area + (hpagesize*i), 0, 1);
         }

peterc@Diprotodon:/usr/src/qemu/tests/m

[Peter Chubb (peter-chubb-1)]

>>>>> "Peter" == Peter Chubb <email address hidden> writes:
This change fixes it.

> diff --git a/exec.c b/exec.c
> index 2435d9e..b387d28 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -1070,7 +1070,7 @@ static void *file_ram_alloc(RAMBlock *block,
> }
>
> /* MAP_POPULATE silently ignores failures */
> - for (i = 0; i < (memory/hpagesize); i++) {
> + for (i = 0; i < (memory/hpagesize)-1; i++) {
> memset(area + (hpagesize*i), 0, 1);
> }

I don't know why this fixes the issue. Hence, no signed-off-by line, etc.

My guess is that the memset zeros something it shouldn't off the end of
the array (but that doesn't make sense to me!)

Peter C
--
Dr Peter Chubb peter.chubb AT nicta.com.au
http://www.ssrg.nicta.com.au Software Systems Research Group/NICTA

[Thomas Huth (th-huth)]

tests/multiboot seems to work with current git again, so I assume this issue has been fixed? Or is there something left to do?

[Launchpad Janitor (janitor)]

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