KVM: PPC: Avoid patching paravirt template code

Currently we patch the whole code include paravirt template code.
This isn't safe for scratch area and has impact to performance.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 16 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 04d4b5aa6dca..62bdf2389669 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -665,6 +665,9 @@ static void kvm_check_ins(u32 *inst, u32 features)
         }
 }
 
+extern u32 kvm_template_start[];
+extern u32 kvm_template_end[];
+
 static void kvm_use_magic_page(void)
 {
         u32 *p;
@@ -692,8 +695,14 @@ static void kvm_use_magic_page(void)
          */
         local_irq_disable();
 
-        for (p = start; p < end; p++)
+        for (p = start; p < end; p++) {
+                /* Avoid patching the template code */
+                if (p >= kvm_template_start && p < kvm_template_end) {
+                        p = kvm_template_end - 1;
+                        continue;
+                }
                 kvm_check_ins(p, features);
+        }
 
         local_irq_enable();
 
diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S
index 801058dd74db..e291cf3cf954 100644
--- a/arch/powerpc/kernel/kvm_emul.S
+++ b/arch/powerpc/kernel/kvm_emul.S
@@ -66,6 +66,9 @@ kvm_hypercall_start:
            shared->critical == r1 and r2 is always != r1 */             \
         STL64(r2, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);
 
+.global kvm_template_start
+kvm_template_start:
+
 .global kvm_emulate_mtmsrd
 kvm_emulate_mtmsrd:
 
@@ -350,3 +353,6 @@ kvm_emulate_mtsrin_orig_ins_offs:
 .global kvm_emulate_mtsrin_len
 kvm_emulate_mtsrin_len:
         .long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4
+
+.global kvm_template_end
+kvm_template_end: