[PATCH] i386: PARAVIRT: Allow boot-time disable of paravirt_ops patching

Add "noreplace-paravirt" to disable paravirt_ops patching.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 242b3a0..38d7db3 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -64,6 +64,7 @@ parameter is applicable:
        GENERIC_TIME The generic timeofday code is enabled.
        NFS     Appropriate NFS support is enabled.
        OSS     OSS sound support is enabled.
+       PV_OPS  A paravirtualized kernel
        PARIDE  The ParIDE subsystem is enabled.
        PARISC  The PA-RISC architecture is enabled.
        PCI     PCI bus support is enabled.
@@ -1164,6 +1165,8 @@ and is between 256 and 4096 characters. It is defined in the file
 
        nomce           [IA-32] Machine Check Exception
 
+       noreplace-paravirt      [IA-32,PV_OPS] Don't patch paravirt_ops
+
        noreplace-smp   [IA-32,SMP] Don't replace SMP instructions
                        with UP alternatives
 

diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c
index c5d037c..080a59d 100644 (file)
--- a/arch/i386/kernel/alternative.c
+++ b/arch/i386/kernel/alternative.c
@@ -30,6 +30,16 @@ static int __init setup_noreplace_smp(char *str)
 }
 __setup("noreplace-smp", setup_noreplace_smp);
 
+#ifdef CONFIG_PARAVIRT
+static int noreplace_paravirt = 0;
+
+static int __init setup_noreplace_paravirt(char *str)
+{
+       noreplace_paravirt = 1;
+       return 1;
+}
+__setup("noreplace-paravirt", setup_noreplace_paravirt);
+#endif
 
 #define DPRINTK(fmt, args...) if (debug_alternative) \
        printk(KERN_DEBUG fmt, args)
@@ -330,6 +340,9 @@ void apply_paravirt(struct paravirt_patch_site *start,
 {
        struct paravirt_patch_site *p;
 
+       if (noreplace_paravirt)
+               return;
+
        for (p = start; p < end; p++) {
                unsigned int used;