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Commit c9ccf30d authored by Rusty Russell's avatar Rusty Russell Committed by Andi Kleen
Browse files

[PATCH] paravirt: Add startup infrastructure for paravirtualization 



1) Each hypervisor writes a probe function to detect whether we are
   running under that hypervisor.  paravirt_probe() registers this
   function.

2) If vmlinux is booted with ring != 0, we call all the probe
   functions (with registers except %esp intact) in link order: the
   winner will not return.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
parent d7cd5611

arch/i386/kernel/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -39,6 +39,8 @@ obj-$(CONFIG_VM86) += vm86.o 
obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o

obj-$(CONFIG_HPET_TIMER) 	+= hpet.o

obj-$(CONFIG_K8_NB)		+= k8.o



# Make sure this is linked after any other paravirt_ops structs: see head.S

obj-$(CONFIG_PARAVIRT)		+= paravirt.o



EXTRA_AFLAGS   := -traditional

arch/i386/kernel/head.S

+33 −0
Original line number Diff line number Diff line
@@ -55,6 +55,12 @@ 
 */

ENTRY(startup_32)



#ifdef CONFIG_PARAVIRT

        movl %cs, %eax

        testl $0x3, %eax

        jnz startup_paravirt

#endif



/*

 * Set segments to known values.

 */
@@ -486,6 +492,33 @@ ignore_int: 
#endif

	iret



#ifdef CONFIG_PARAVIRT

startup_paravirt:

	cld

 	movl $(init_thread_union+THREAD_SIZE),%esp



	/* We take pains to preserve all the regs. */

	pushl	%edx

	pushl	%ecx

	pushl	%eax



	/* paravirt.o is last in link, and that probe fn never returns */

	pushl	$__start_paravirtprobe

1:

	movl	0(%esp), %eax

	pushl	(%eax)

	movl	8(%esp), %eax

	call	*(%esp)

	popl	%eax



	movl	4(%esp), %eax

	movl	8(%esp), %ecx

	movl	12(%esp), %edx



	addl	$4, (%esp)

	jmp	1b

#endif



/*

 * Real beginning of normal "text" segment

 */

arch/i386/kernel/paravirt.c

+4 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/module.h>

#include <linux/efi.h>

#include <linux/bcd.h>

#include <linux/start_kernel.h>



#include <asm/bug.h>

#include <asm/paravirt.h>
@@ -387,6 +388,9 @@ static int __init print_banner(void) 
}

core_initcall(print_banner);



/* We simply declare start_kernel to be the paravirt probe of last resort. */

paravirt_probe(start_kernel);



struct paravirt_ops paravirt_ops = {

	.name = "bare hardware",

	.paravirt_enabled = 0,

arch/i386/kernel/vmlinux.lds.S

+6 −0
Original line number Diff line number Diff line
@@ -65,6 +65,12 @@ SECTIONS 
	CONSTRUCTORS

	} :data



  __start_paravirtprobe = .;

  .paravirtprobe : AT(ADDR(.paravirtprobe) - LOAD_OFFSET) {

	*(.paravirtprobe)

  }

  __stop_paravirtprobe = .;



  . = ALIGN(4096);

  .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {

  	__nosave_begin = .;

include/asm-i386/paravirt.h

+5 −0
Original line number Diff line number Diff line
@@ -120,6 +120,11 @@ struct paravirt_ops 
	void (fastcall *iret)(void);

};



/* Mark a paravirt probe function. */

#define paravirt_probe(fn)						\

 static asmlinkage void (*__paravirtprobe_##fn)(void) __attribute_used__ \

		__attribute__((__section__(".paravirtprobe"))) = fn



extern struct paravirt_ops paravirt_ops;



#define paravirt_enabled() (paravirt_ops.paravirt_enabled)