[PATCH 1/6] kvmppc: add hypercall infrastructure - host part

[ehrhardt@linux.vnet.ibm.com]

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

This adds the host portion of the hypercall infrastructure which receives
the guest calls - no specific hcall function is implemented in this patch.
Hypercall ABI is beat style using sycall+arg. A new kvm exit stat counter
for hypercalls is added too.

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

[diffstat]
 arch/powerpc/kvm/booke_guest.c      |   11 +++++++++--
 arch/powerpc/kvm/booke_interrupts.S |    9 +++++++++
 arch/powerpc/kvm/emulate.c          |   16 ++++++++++++++++
 include/asm-powerpc/kvm_host.h      |    1 +
 include/asm-powerpc/kvm_para.h      |    4 ++++
 5 files changed, 39 insertions(+), 2 deletions(-)

[diff]

diff --git a/arch/powerpc/kvm/booke_guest.c b/arch/powerpc/kvm/booke_guest.c
--- a/arch/powerpc/kvm/booke_guest.c
+++ b/arch/powerpc/kvm/booke_guest.c
@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <linux/vmalloc.h>
 #include <linux/fs.h>
+#include <linux/kvm_para.h>
 #include <asm/cputable.h>
 #include <asm/uaccess.h>
 #include <asm/kvm_ppc.h>
@@ -44,6 +45,7 @@
 	{ "dtlb_r",     VCPU_STAT(dtlb_real_miss_exits) },
 	{ "dtlb_v",     VCPU_STAT(dtlb_virt_miss_exits) },
 	{ "sysc",       VCPU_STAT(syscall_exits) },
+	{ "hcall",      VCPU_STAT(hcall_exits) },
 	{ "isi",        VCPU_STAT(isi_exits) },
 	{ "dsi",        VCPU_STAT(dsi_exits) },
 	{ "inst_emu",   VCPU_STAT(emulated_inst_exits) },
@@ -327,8 +329,13 @@
 		break;
 
 	case BOOKE_INTERRUPT_SYSCALL:
-		kvmppc_queue_exception(vcpu, exit_nr);
-		vcpu->stat.syscall_exits++;
+		if (vcpu->arch.last_inst = KVM_HYPERCALL_BIN) {
+			kvmppc_do_hypercall(vcpu);
+			vcpu->stat.hcall_exits++;
+		} else {
+			kvmppc_queue_exception(vcpu, exit_nr);
+			vcpu->stat.syscall_exits++;
+		}
 		r = RESUME_GUEST;
 		break;
 
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
--- a/arch/powerpc/kvm/booke_interrupts.S
+++ b/arch/powerpc/kvm/booke_interrupts.S
@@ -43,7 +43,10 @@
 
 #define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
                         (1<<BOOKE_INTERRUPT_DTLB_MISS) | \
+                        (1<<BOOKE_INTERRUPT_SYSCALL) | \
                         (1<<BOOKE_INTERRUPT_DEBUG))
+
+#define NEED_PRE_INST_MASK (1<<BOOKE_INTERRUPT_SYSCALL)
 
 #define NEED_DEAR_MASK ((1<<BOOKE_INTERRUPT_DATA_STORAGE) | \
                         (1<<BOOKE_INTERRUPT_DTLB_MISS))
@@ -114,6 +117,12 @@
 	mfmsr	r8
 	ori	r7, r8, MSR_DS
 	mtmsr	r7
+
+	andi.	r7, r6, NEED_PRE_INST_MASK
+	beq	..skip_syscall_srr0pc
+	subi	r9, r9, 4
+
+..skip_syscall_srr0pc:
 	isync
 	lwz	r9, 0(r9)
 	mtmsr	r8
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -22,6 +22,7 @@
 #include <linux/types.h>
 #include <linux/string.h>
 #include <linux/kvm_host.h>
+#include <linux/kvm_para.h>
 
 #include <asm/dcr.h>
 #include <asm/dcr-regs.h>
@@ -201,6 +202,21 @@
 {
 	vcpu->arch.pc = vcpu->arch.srr0;
 	kvmppc_set_msr(vcpu, vcpu->arch.srr1);
+}
+
+int kvmppc_do_hypercall(struct kvm_vcpu *vcpu)
+{
+	u32 ret = 0;
+
+	switch (vcpu->arch.gpr[11]) {
+	default:
+		printk(KERN_ERR "unknown hypercall %d\n", vcpu->arch.gpr[11]);
+		kvmppc_dump_vcpu(vcpu);
+		ret = -ENOSYS;
+	}
+
+	vcpu->arch.gpr[3] = ret;
+	return ret;
 }
 
 /* XXX to do:
diff --git a/include/asm-powerpc/kvm_host.h b/include/asm-powerpc/kvm_host.h
--- a/include/asm-powerpc/kvm_host.h
+++ b/include/asm-powerpc/kvm_host.h
@@ -56,6 +56,7 @@
 	u32 dtlb_real_miss_exits;
 	u32 dtlb_virt_miss_exits;
 	u32 syscall_exits;
+	u32 hcall_exits;
 	u32 isi_exits;
 	u32 dsi_exits;
 	u32 emulated_inst_exits;
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
@@ -22,6 +22,8 @@
 
 #ifdef __KERNEL__
 
+#define KVM_HYPERCALL_BIN 0x44000022
+
 static inline int kvm_para_available(void)
 {
 	return 0;
@@ -32,6 +34,8 @@
 	return 0;
 }
 
+extern int kvmppc_do_hypercall(struct kvm_vcpu *vcpu);
+
 #endif /* __KERNEL__ */
 
 #endif /* __POWERPC_KVM_PARA_H__ */