KVM: PPC: Introduce branch patching helper
authorAlexander Graf <agraf@suse.de>
Thu, 29 Jul 2010 12:48:02 +0000 (14:48 +0200)
committerAvi Kivity <avi@redhat.com>
Sun, 24 Oct 2010 08:50:54 +0000 (10:50 +0200)
We will need to patch several instruction streams over to a different
code path, so we need a way to patch a single instruction with a branch
somewhere else.

This patch adds a helper to facilitate this patching.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
arch/powerpc/kernel/kvm.c

index 926f93f..239a70d 100644 (file)
@@ -107,6 +107,20 @@ static void kvm_patch_ins_nop(u32 *inst)
        kvm_patch_ins(inst, KVM_INST_NOP);
 }
 
+static void kvm_patch_ins_b(u32 *inst, int addr)
+{
+#ifdef CONFIG_RELOCATABLE
+       /* On relocatable kernels interrupts handlers and our code
+          can be in different regions, so we don't patch them */
+
+       extern u32 __end_interrupts;
+       if ((ulong)inst < (ulong)&__end_interrupts)
+               return;
+#endif
+
+       kvm_patch_ins(inst, KVM_INST_B | (addr & KVM_INST_B_MASK));
+}
+
 static u32 *kvm_alloc(int len)
 {
        u32 *p;