The purpose of struct boot_module is to encapsulate the state of boot module as
it is processed by Xen. Locating boot module state struct boot_module reduces
the number of global variables as well as the number of state variables that
must be passed around. It also lays the groundwork for hyperlaunch mult-domain
construction, where multiple instances of state variables like headroom will be
needed.
Signed-off-by: Daniel P. Smith <dpsm...@apertussolutions.com>
Reviewed-by: Jason Andryuk <jason.andr...@amd.com>
---
Changes since v6:
- add blank line to separate comment from line above it
Changes since v5:
- reword and expand comment on headroom
- consolidated declaration and assignment
---
xen/arch/x86/include/asm/bootinfo.h | 14 ++++++++++++++
xen/arch/x86/setup.c | 21 ++++++++++++---------
2 files changed, 26 insertions(+), 9 deletions(-)
diff --git a/xen/arch/x86/include/asm/bootinfo.h
b/xen/arch/x86/include/asm/bootinfo.h
index ffa443406747..59e6696f9671 100644
--- a/xen/arch/x86/include/asm/bootinfo.h
+++ b/xen/arch/x86/include/asm/bootinfo.h
@@ -17,6 +17,20 @@
struct boot_module {
/* Transitionary only */
module_t *mod;
+
+ /*
+ * A boot module may contain a compressed kernel that will require
+ * additional space, before the module data, into which the kernel will be
+ * decompressed.
+ *
+ * Memory layout at boot:
+ * [ compressed kernel ]
+ * After boot module relocation:
+ * [ estimated headroom + PAGE_SIZE rounding ][ compressed kernel ]
+ * After kernel decompression:
+ * [ decompressed kernel ][ unused rounding ]
+ */
+ unsigned long headroom;
};
/*
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 1eafa0a61e0e..48809aa94451 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1028,7 +1028,7 @@ void asmlinkage __init noreturn __start_xen(unsigned long
mbi_p)
struct boot_info *bi;
multiboot_info_t *mbi;
module_t *mod;
- unsigned long nr_pages, raw_max_page, modules_headroom, module_map[1];
+ unsigned long nr_pages, raw_max_page, module_map[1];
int i, j, e820_warn = 0, bytes = 0;
unsigned long eb_start, eb_end;
bool acpi_boot_table_init_done = false, relocated = false;
@@ -1394,7 +1394,10 @@ void asmlinkage __init noreturn __start_xen(unsigned
long mbi_p)
mod[bi->nr_modules].mod_end = __2M_rwdata_end - _stext;
}
- modules_headroom = bzimage_headroom(bootstrap_map(mod), mod->mod_end);
+ bi->mods[0].headroom =
+ bzimage_headroom(bootstrap_map(bi->mods[0].mod),
+ bi->mods[0].mod->mod_end);
+
bootstrap_map(NULL);
#ifndef highmem_start
@@ -1479,8 +1482,8 @@ void asmlinkage __init noreturn __start_xen(unsigned long
mbi_p)
* decompressor overheads of mod[0] (the dom0 kernel). When we
* move mod[0], we incorporate this as extra space at the start.
*/
- unsigned long headroom = j ? 0 : modules_headroom;
- unsigned long size = PAGE_ALIGN(headroom + mod[j].mod_end);
+ struct boot_module *bm = &bi->mods[j];
+ unsigned long size = PAGE_ALIGN(bm->headroom + mod[j].mod_end);
if ( mod[j].reserved )
continue;
@@ -1493,14 +1496,14 @@ void asmlinkage __init noreturn __start_xen(unsigned
long mbi_p)
continue;
if ( s < end &&
- (headroom ||
+ (bm->headroom ||
((end - size) >> PAGE_SHIFT) > mod[j].mod_start) )
{
- move_memory(end - size + headroom,
+ move_memory(end - size + bm->headroom,
(uint64_t)mod[j].mod_start << PAGE_SHIFT,
mod[j].mod_end);
mod[j].mod_start = (end - size) >> PAGE_SHIFT;
- mod[j].mod_end += headroom;
+ mod[j].mod_end += bm->headroom;
mod[j].reserved = 1;
}
}
@@ -1527,7 +1530,7 @@ void asmlinkage __init noreturn __start_xen(unsigned long
mbi_p)
#endif
}
- if ( modules_headroom && !mod->reserved )
+ if ( bi->mods[0].headroom && !mod->reserved )
panic("Not enough memory to relocate the dom0 kernel image\n");
for ( i = 0; i < bi->nr_modules; ++i )
{
@@ -2079,7 +2082,7 @@ void asmlinkage __init noreturn __start_xen(unsigned long
mbi_p)
* We're going to setup domain0 using the module(s) that we stashed safely
* above our heap. The second module, if present, is an initrd ramdisk.
*/
- dom0 = create_dom0(mod, modules_headroom,
+ dom0 = create_dom0(mod, bi->mods[0].headroom,
initrdidx < bi->nr_modules ? mod + initrdidx : NULL,
kextra, bi->loader);
if ( !dom0 )
--
2.30.2
