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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86: partially revert use of 2M mappings for hypervisor image
commit 0b8a17244475855dc3f32c29500f56c449de8013
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Mar 15 12:21:04 2016 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Mar 15 12:21:04 2016 +0100
x86: partially revert use of 2M mappings for hypervisor image
As explained by Andrew in
http://lists.xenproject.org/archives/html/xen-devel/2016-03/msg01380.html
that change makes the uncompressed xen.gz image too large for certain
boot environments. As a result this change makes some of the effects of
commits cf393624ee ("x86: use 2M superpages for text/data/bss
mappings") and 53aa3dde17 ("x86: unilaterally remove .init mappings")
conditional, restoring alternative previous code where necessary. This
is so that xen.efi can still benefit from the new mechanisms, as it is
unaffected by said limitations.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/setup.c | 35 ++++++++++++++++++++++++++++++++---
xen/arch/x86/xen.lds.S | 12 ++++++++++++
2 files changed, 44 insertions(+), 3 deletions(-)
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 8431f06..a8bf2c9 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -497,6 +497,17 @@ static void __init kexec_reserve_area(struct e820map *e820)
#endif
}
+static inline bool_t using_2M_mapping(void)
+{
+ return !l1_table_offset((unsigned long)__2M_text_end) &&
+ !l1_table_offset((unsigned long)__2M_rodata_start) &&
+ !l1_table_offset((unsigned long)__2M_rodata_end) &&
+ !l1_table_offset((unsigned long)__2M_init_start) &&
+ !l1_table_offset((unsigned long)__2M_init_end) &&
+ !l1_table_offset((unsigned long)__2M_rwdata_start) &&
+ !l1_table_offset((unsigned long)__2M_rwdata_end);
+}
+
static void noinline init_done(void)
{
void *va;
@@ -510,9 +521,18 @@ static void noinline init_done(void)
clear_page(va);
/* Destroy Xen's mappings, and reuse the pages. */
- destroy_xen_mappings((unsigned long)&__2M_init_start,
- (unsigned long)&__2M_init_end);
- init_xenheap_pages(__pa(__2M_init_start), __pa(__2M_init_end));
+ if ( using_2M_mapping() )
+ {
+ destroy_xen_mappings((unsigned long)&__2M_init_start,
+ (unsigned long)&__2M_init_end);
+ init_xenheap_pages(__pa(__2M_init_start), __pa(__2M_init_end));
+ }
+ else
+ {
+ destroy_xen_mappings((unsigned long)&__init_begin,
+ (unsigned long)&__init_end);
+ init_xenheap_pages(__pa(__init_begin), __pa(__init_end));
+ }
printk("Freed %ldkB init memory.\n", (long)(__init_end-__init_begin)>>10);
@@ -922,6 +942,8 @@ void __init noreturn __start_xen(unsigned long mbi_p)
* Undo the temporary-hooking of the l1_identmap. __2M_text_start
* is contained in this PTE.
*/
+ BUG_ON(l2_table_offset((unsigned long)_erodata) ==
+ l2_table_offset((unsigned long)_stext));
*pl2e++ = l2e_from_pfn(xen_phys_start >> PAGE_SHIFT,
PAGE_HYPERVISOR_RX | _PAGE_PSE);
for ( i = 1; i < L2_PAGETABLE_ENTRIES; i++, pl2e++ )
@@ -931,6 +953,13 @@ void __init noreturn __start_xen(unsigned long mbi_p)
if ( !(l2e_get_flags(*pl2e) & _PAGE_PRESENT) )
continue;
+ if ( !using_2M_mapping() )
+ {
+ *pl2e = l2e_from_intpte(l2e_get_intpte(*pl2e) +
+ xen_phys_start);
+ continue;
+ }
+
if ( i < l2_table_offset((unsigned long)&__2M_text_end) )
{
flags = PAGE_HYPERVISOR_RX | _PAGE_PSE;
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 2922165..5cb9741 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -53,11 +53,14 @@ SECTIONS
_etext = .; /* End of text section */
} :text = 0x9090
+#ifdef EFI
. = ALIGN(MB(2));
+#endif
__2M_text_end = .;
__2M_rodata_start = .; /* Start of 2M superpages, mapped RO. */
.rodata : {
+ _srodata = .;
/* Bug frames table */
. = ALIGN(4);
__start_bug_frames = .;
@@ -79,9 +82,12 @@ SECTIONS
*(.lockprofile.data)
__lock_profile_end = .;
#endif
+ _erodata = .;
} :text
+#ifdef EFI
. = ALIGN(MB(2));
+#endif
__2M_rodata_end = .;
__2M_init_start = .; /* Start of 2M superpages, mapped RWX (boot
only). */
@@ -148,7 +154,9 @@ SECTIONS
. = ALIGN(PAGE_SIZE);
__init_end = .;
+#ifdef EFI
. = ALIGN(MB(2));
+#endif
__2M_init_end = .;
__2M_rwdata_start = .; /* Start of 2M superpages, mapped RW. */
@@ -200,7 +208,9 @@ SECTIONS
} :text
_end = . ;
+#ifdef EFI
. = ALIGN(MB(2));
+#endif
__2M_rwdata_end = .;
#ifdef EFI
@@ -250,6 +260,7 @@ ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE,
"kexec_reloc is too large")
#endif
ASSERT(IS_ALIGNED(__2M_text_start, MB(2)), "__2M_text_start misaligned")
+#ifdef EFI
ASSERT(IS_ALIGNED(__2M_text_end, MB(2)), "__2M_text_end misaligned")
ASSERT(IS_ALIGNED(__2M_rodata_start, MB(2)), "__2M_rodata_start misaligned")
ASSERT(IS_ALIGNED(__2M_rodata_end, MB(2)), "__2M_rodata_end misaligned")
@@ -257,6 +268,7 @@ ASSERT(IS_ALIGNED(__2M_init_start, MB(2)),
"__2M_init_start misaligned")
ASSERT(IS_ALIGNED(__2M_init_end, MB(2)), "__2M_init_end misaligned")
ASSERT(IS_ALIGNED(__2M_rwdata_start, MB(2)), "__2M_rwdata_start misaligned")
ASSERT(IS_ALIGNED(__2M_rwdata_end, MB(2)), "__2M_rwdata_end misaligned")
+#endif
ASSERT(IS_ALIGNED(cpu0_stack, STACK_SIZE), "cpu0_stack misaligned")
--
generated by git-patchbot for /home/xen/git/xen.git#master
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