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authorZachary Amsden <zach@vmware.com>2006-01-06 00:11:47 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-06 08:33:33 -0800
commit7c4cb60e5b97677424e95baee9c29df54b26e6ba (patch)
treea2ad6e6104e153d15bc4bfbb67f74b0e05fea03c /arch/i386/kernel/head.S
parent599a6e8ca4ff7f453f847217ecc2718d68e3b0f6 (diff)
[PATCH] x86: GDT alignment fix
Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by: Zachary Amsden <zach@vmware.com> Cc: "Seth, Rohit" <rohit.seth@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel/head.S')
-rw-r--r--arch/i386/kernel/head.S2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index e437fb36749..870f20bf33c 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -525,3 +525,5 @@ ENTRY(cpu_gdt_table)
.quad 0x0000000000000000 /* 0xf0 - unused */
.quad 0x0000000000000000 /* 0xf8 - GDT entry 31: double-fault TSS */
+ /* Be sure this is zeroed to avoid false validations in Xen */
+ .fill PAGE_SIZE_asm / 8 - GDT_ENTRIES,8,0