[PATCH 3/6] kvmppc: add hypercall infrastructure - guest part

[ehrhardt@linux.vnet.ibm.com]

From: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>

This adds the guest portion of the hypercall infrastructure, basically an
illegal instruction with a defined layout.
See http://kvm.qumranet.com/kvmwiki/PowerPC_Hypercall_ABI for more detail
on the hypercall ABI for powerpc.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
---

[diffstat]
 kvm_para.h |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

[diff]
diff --git a/include/asm-powerpc/kvm_para.h b/include/asm-powerpc/kvm_para.h
--- a/include/asm-powerpc/kvm_para.h
+++ b/include/asm-powerpc/kvm_para.h
@@ -25,6 +25,8 @@
 #ifdef __KERNEL__
 
 #include <linux/of.h>
+
+#define KVM_HYPERCALL_BIN 0x03ffffff
 
 static struct kvmppc_para_features {
 	char *dtcell;
@@ -63,6 +65,20 @@
 
 void kvm_guest_init(void);
 
+static inline long kvm_hypercall1(unsigned int nr, unsigned long p1)
+{
+	register unsigned long hcall asm ("r0") = nr;
+	register unsigned long arg1 asm ("r3") = p1;
+	register long ret asm ("r11");
+
+	asm volatile(".long %1"
+			: "=r"(ret)
+			: "i"(KVM_HYPERCALL_BIN), "r"(hcall), "r"(arg1)
+			: "r4", "r5", "r6", "r7", "r8",
+			  "r9", "r10", "r12", "cc");
+	return ret;
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* __POWERPC_KVM_PARA_H__ */