[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: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index 5b14e95..edef508 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -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 @@
#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
*/