KVM: PPC: Add mtsrin PV code
This is the guest side of the mtsr acceleration. Using this a guest can now
call mtsrin with almost no overhead as long as it ensures that it only uses
it with (MSR_IR|MSR_DR) == 0. Linux does that, so we're good.
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S
index 3199f65..a6e97e7 100644
--- a/arch/powerpc/kernel/kvm_emul.S
+++ b/arch/powerpc/kernel/kvm_emul.S
@@ -245,3 +245,53 @@
.global kvm_emulate_wrteei_len
kvm_emulate_wrteei_len:
.long (kvm_emulate_wrteei_end - kvm_emulate_wrteei) / 4
+
+
+.global kvm_emulate_mtsrin
+kvm_emulate_mtsrin:
+
+ SCRATCH_SAVE
+
+ LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
+ andi. r31, r31, MSR_DR | MSR_IR
+ beq kvm_emulate_mtsrin_reg1
+
+ SCRATCH_RESTORE
+
+kvm_emulate_mtsrin_orig_ins:
+ nop
+ b kvm_emulate_mtsrin_branch
+
+kvm_emulate_mtsrin_reg1:
+ /* rX >> 26 */
+ rlwinm r30,r0,6,26,29
+
+kvm_emulate_mtsrin_reg2:
+ stw r0, (KVM_MAGIC_PAGE + KVM_MAGIC_SR)(r30)
+
+ SCRATCH_RESTORE
+
+ /* Go back to caller */
+kvm_emulate_mtsrin_branch:
+ b .
+kvm_emulate_mtsrin_end:
+
+.global kvm_emulate_mtsrin_branch_offs
+kvm_emulate_mtsrin_branch_offs:
+ .long (kvm_emulate_mtsrin_branch - kvm_emulate_mtsrin) / 4
+
+.global kvm_emulate_mtsrin_reg1_offs
+kvm_emulate_mtsrin_reg1_offs:
+ .long (kvm_emulate_mtsrin_reg1 - kvm_emulate_mtsrin) / 4
+
+.global kvm_emulate_mtsrin_reg2_offs
+kvm_emulate_mtsrin_reg2_offs:
+ .long (kvm_emulate_mtsrin_reg2 - kvm_emulate_mtsrin) / 4
+
+.global kvm_emulate_mtsrin_orig_ins_offs
+kvm_emulate_mtsrin_orig_ins_offs:
+ .long (kvm_emulate_mtsrin_orig_ins - kvm_emulate_mtsrin) / 4
+
+.global kvm_emulate_mtsrin_len
+kvm_emulate_mtsrin_len:
+ .long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4