On 2024-04-26 10:01, Andrew Cooper wrote:
modules_headroom is a misleading name as it applies strictly to mod[0] only,
and the movement loop is deeply unintuitive and completely undocumented.
Provide help to whomever needs to look at this code next.
Signed-off-by: Andrew Cooper <[email protected]>
---
CC: Jan Beulich <[email protected]>
CC: Roger Pau Monné <[email protected]>
CC: Stefano Stabellini <[email protected]>
CC: Daniel Smith <[email protected]>
CC: Christopher Clark <[email protected]>
---
xen/arch/x86/setup.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index caf235c6286d..59907fae095f 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1432,6 +1432,11 @@ void asmlinkage __init noreturn __start_xen(unsigned
long mbi_p)
/* Is the region suitable for relocating the multiboot modules? */
for ( j = mbi->mods_count - 1; j >= 0; j-- )
{
+ /*
+ * 'headroom' is a guess for the decompressed size and
+ * decompressor overheads of mod[0] (the dom0 kernel). When we
+ * move mod[0], we incorperate this as extra space at the start.
incorporate
With that:
Reviewed-by: Jason Andryuk <[email protected]>
Thanks,
Jason
+ */
unsigned long headroom = j ? 0 : modules_headroom;
unsigned long size = PAGE_ALIGN(headroom + mod[j].mod_end);
