[PATCH 14/33] KVM: PPC: Add std instruction emulation

[Alexander Graf <agraf@xxxxxxx>]

This patch implements full emulation for the "std" instruction. It also
implements all the the groundwork required to emulate store instructions
in general as well as MMIO exits in emulated sections.

Signed-off-by: Alexander Graf <agraf@xxxxxxx>
---
 arch/powerpc/kvm/emulate.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++
 arch/powerpc/kvm/powerpc.c |  6 +++-
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 7bf247e0..0a5355d 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -305,10 +305,86 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);
 
+static ulong get_addr(struct kvm_vcpu *vcpu, int offset, int ra)
+{
+	ulong addr = 0;
+#if defined(CONFIG_PPC_BOOK3E_64)
+	ulong msr_64bit = MSR_CM;
+#elif defined(CONFIG_PPC_BOOK3S_64)
+	ulong msr_64bit = MSR_SF;
+#else
+	ulong msr_64bit = 0;
+#endif
+
+	if (ra)
+		addr = kvmppc_get_gpr(vcpu, ra);
+
+	addr += offset;
+	if (!(kvmppc_get_msr(vcpu) & msr_64bit))
+		addr = (uint32_t)addr;
+
+	return addr;
+}
+
+static int kvmppc_emulate_store(struct kvm_vcpu *vcpu, ulong addr, u64 value,
+				int size)
+{
+	ulong paddr = addr;
+	int r;
+
+	if (kvmppc_need_byteswap(vcpu)) {
+		switch (size) {
+		case 1: *(u8*)&value = value; break;
+		case 2: *(u16*)&value = swab16(value); break;
+		case 4: *(u32*)&value = swab32(value); break;
+		case 8: *(u64*)&value = swab64(value); break;
+		}
+	} else {
+		switch (size) {
+		case 1: *(u8*)&value = value; break;
+		case 2: *(u16*)&value = value; break;
+		case 4: *(u32*)&value = value; break;
+		case 8: *(u64*)&value = value; break;
+		}
+	}
+
+	r = kvmppc_st(vcpu, &paddr, size, &value, true);
+	switch (r) {
+	case -ENOENT:
+#ifdef CONFIG_PPC_BOOK3S
+		kvmppc_core_queue_data_storage(vcpu, addr,
+			DSISR_ISSTORE | DSISR_NOHPTE);
+#else
+		kvmppc_core_queue_dtlb_miss(vcpu, addr, ESR_DST | ESR_ST);
+#endif
+		r = EMULATE_AGAIN;
+		break;
+	case -EPERM:
+#ifdef CONFIG_PPC_BOOK3S
+		kvmppc_core_queue_data_storage(vcpu, addr,
+			DSISR_ISSTORE | DSISR_PROTFAULT);
+#else
+		kvmppc_core_queue_data_storage(vcpu, addr, ESR_ST);
+#endif
+		r = EMULATE_AGAIN;
+		break;
+	case EMULATE_DO_MMIO:
+		vcpu->stat.mmio_exits++;
+		vcpu->arch.paddr_accessed = paddr;
+		vcpu->arch.vaddr_accessed = addr;
+		vcpu->run->exit_reason = KVM_EXIT_MMIO;
+		r = kvmppc_emulate_loadstore(vcpu);
+		break;
+	}
+
+	return r;
+}
+
 /* Emulates privileged and non-privileged instructions */
 int kvmppc_emulate_any_instruction(struct kvm_vcpu *vcpu)
 {
 	u32 inst = kvmppc_get_last_inst(vcpu);
+	ulong addr, value;
 	enum emulation_result emulated = EMULATE_DONE;
 	int advance = 1;
 
@@ -316,8 +392,14 @@ int kvmppc_emulate_any_instruction(struct kvm_vcpu *vcpu)
 
 	/* Try non-privileged instructions */
 	switch (get_op(inst)) {
+	case OP_STD:
+		addr = get_addr(vcpu, (s16)get_d(inst), get_ra(inst));
+		value = kvmppc_get_gpr(vcpu, get_rs(inst));
+		emulated = kvmppc_emulate_store(vcpu, addr, value, 8);
+		break;
 	default:
 		emulated = EMULATE_FAIL;
+		break;
 	}
 
 	/* Try privileged instructions */
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index f2de6f4..0a326e1 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -158,8 +158,12 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu)
 		if (kvmppc_needs_emulation(vcpu)) {
 			/* Emulate one instruction, then try again */
 			local_irq_enable();
+
 			vcpu->arch.last_inst = KVM_INST_FETCH_FAILED;
-			kvmppc_emulate_any_instruction(vcpu);
+			r = kvmppc_emulate_any_instruction(vcpu);
+			if (r == EMULATE_DO_MMIO)
+				return 0;
+
 			hard_irq_disable();
 			continue;
 		}
-- 
1.8.1.4

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