Attachment 217341 Details for Bug 320111 – Patch to fix the slow boot

[patch] Patch to fix the slow boot

boot-decompress-vt-fix.patch (text/plain), 1.15 KB, created by Daniel Buchmann on 2007-10-05 13:36:13 UTC

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Creator: Daniel Buchmann

Created: 2007-10-05 13:36:13 UTC

Size: 1.15 KB

patch

obsolete

>VT is very picky about when it can enter execution.
>Get all segments setup and get LDT and TR into valid state to allow
>VT execution under VMware and KVM (untested).
>
>This makes the boot decompression run under VT, which makes it several
>orders of magnitude faster on 64-bit Intel hardware.
>
>Before, I was seeing times up to a minute or more to decompress a 1.3MB kernel
>on a very fast box.
>
>Signed-off-by: Zachary Amsden <zach@vmware.com>
>
>
>===================================================================
>--- a/arch/x86_64/boot/compressed/head.S
>+++ a/arch/x86_64/boot/compressed/head.S
>@@ -195,6 +195,11 @@
> 	movl	%eax, %ds
> 	movl	%eax, %es
> 	movl	%eax, %ss
>+	movl	%eax, %fs
>+	movl	%eax, %gs
>+	lldt	%ax
>+	movl    $0x20, %eax
>+	ltr	%ax
> 
> 	/* Compute the decompressed kernel start address.  It is where
> 	 * we were loaded at aligned to a 2M boundary. %rbp contains the
>@@ -295,6 +300,8 @@
> 	.quad	0x0000000000000000	/* NULL descriptor */
> 	.quad	0x00af9a000000ffff	/* __KERNEL_CS */
> 	.quad	0x00cf92000000ffff	/* __KERNEL_DS */
>+	.quad	0x0080890000000000	/* TS descriptor */
>+	.quad   0x0000000000000000	/* TS continued */
> gdt_end:
> 	.bss
> /* Stack for uncompression */

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Attachments on bug 320111: 217341