[PATCH 26/52] KVM: PPC: Avoid patching paravirt template code

Alexander Graf
2012-01-13T14:31:29Z

From: Liu Yu-B13201 <Yu.Liu@freescale.com>

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>
---
arch/powerpc/kernel/kvm.c | 11 ++++++++++-
arch/powerpc/kernel/kvm_emul.S | 6 ++++++
2 files changed, 16 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 04d4b5a..62bdf23 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 801058d..e291cf3 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:
--
1.6.0.2