KVM: PPC: Convert DSISR to shared page

The DSISR register contains information about a data page fault. It is fully
read/write from inside the guest context and we don't need to worry about
interacting based on writes of this register.

This patch converts all users of the current field to the shared page.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 8274a2d..b5b1961 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -85,7 +85,6 @@
 	u64 hid[6];
 	u64 gqr[8];
 	int slb_nr;
-	u32 dsisr;
 	u64 sdr1;
 	u64 hior;
 	u64 msr_mask;
diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h
index a17dc52..9f7565b 100644
--- a/arch/powerpc/include/asm/kvm_para.h
+++ b/arch/powerpc/include/asm/kvm_para.h
@@ -24,6 +24,7 @@
 
 struct kvm_vcpu_arch_shared {
 	__u64 msr;
+	__u32 dsisr;
 };
 
 #ifdef __KERNEL__
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index 2efe692..eb401b6 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -595,15 +595,16 @@
 	if (page_found == -ENOENT) {
 		/* Page not found in guest PTE entries */
 		vcpu->arch.dear = kvmppc_get_fault_dar(vcpu);
-		to_book3s(vcpu)->dsisr = to_svcpu(vcpu)->fault_dsisr;
+		vcpu->arch.shared->dsisr = to_svcpu(vcpu)->fault_dsisr;
 		vcpu->arch.shared->msr |=
 			(to_svcpu(vcpu)->shadow_srr1 & 0x00000000f8000000ULL);
 		kvmppc_book3s_queue_irqprio(vcpu, vec);
 	} else if (page_found == -EPERM) {
 		/* Storage protection */
 		vcpu->arch.dear = kvmppc_get_fault_dar(vcpu);
-		to_book3s(vcpu)->dsisr = to_svcpu(vcpu)->fault_dsisr & ~DSISR_NOHPTE;
-		to_book3s(vcpu)->dsisr |= DSISR_PROTFAULT;
+		vcpu->arch.shared->dsisr =
+			to_svcpu(vcpu)->fault_dsisr & ~DSISR_NOHPTE;
+		vcpu->arch.shared->dsisr |= DSISR_PROTFAULT;
 		vcpu->arch.shared->msr |=
 			(to_svcpu(vcpu)->shadow_srr1 & 0x00000000f8000000ULL);
 		kvmppc_book3s_queue_irqprio(vcpu, vec);
@@ -867,7 +868,7 @@
 			r = kvmppc_handle_pagefault(run, vcpu, dar, exit_nr);
 		} else {
 			vcpu->arch.dear = dar;
-			to_book3s(vcpu)->dsisr = to_svcpu(vcpu)->fault_dsisr;
+			vcpu->arch.shared->dsisr = to_svcpu(vcpu)->fault_dsisr;
 			kvmppc_book3s_queue_irqprio(vcpu, exit_nr);
 			kvmppc_mmu_pte_flush(vcpu, vcpu->arch.dear, ~0xFFFUL);
 			r = RESUME_GUEST;
@@ -994,7 +995,7 @@
 	}
 	case BOOK3S_INTERRUPT_ALIGNMENT:
 		if (kvmppc_read_inst(vcpu) == EMULATE_DONE) {
-			to_book3s(vcpu)->dsisr = kvmppc_alignment_dsisr(vcpu,
+			vcpu->arch.shared->dsisr = kvmppc_alignment_dsisr(vcpu,
 				kvmppc_get_last_inst(vcpu));
 			vcpu->arch.dear = kvmppc_alignment_dar(vcpu,
 				kvmppc_get_last_inst(vcpu));
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index 35d3c16..9982ff1 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -221,7 +221,7 @@
 				else if (r == -EPERM)
 					dsisr |= DSISR_PROTFAULT;
 
-				to_book3s(vcpu)->dsisr = dsisr;
+				vcpu->arch.shared->dsisr = dsisr;
 				to_svcpu(vcpu)->fault_dsisr = dsisr;
 
 				kvmppc_book3s_queue_irqprio(vcpu,
@@ -327,7 +327,7 @@
 		to_book3s(vcpu)->sdr1 = spr_val;
 		break;
 	case SPRN_DSISR:
-		to_book3s(vcpu)->dsisr = spr_val;
+		vcpu->arch.shared->dsisr = spr_val;
 		break;
 	case SPRN_DAR:
 		vcpu->arch.dear = spr_val;
@@ -440,7 +440,7 @@
 		kvmppc_set_gpr(vcpu, rt, to_book3s(vcpu)->sdr1);
 		break;
 	case SPRN_DSISR:
-		kvmppc_set_gpr(vcpu, rt, to_book3s(vcpu)->dsisr);
+		kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->dsisr);
 		break;
 	case SPRN_DAR:
 		kvmppc_set_gpr(vcpu, rt, vcpu->arch.dear);
diff --git a/arch/powerpc/kvm/book3s_paired_singles.c b/arch/powerpc/kvm/book3s_paired_singles.c
index 626e6ef..749dfbd 100644
--- a/arch/powerpc/kvm/book3s_paired_singles.c
+++ b/arch/powerpc/kvm/book3s_paired_singles.c
@@ -173,7 +173,7 @@
 	/* Page Fault */
 	dsisr = kvmppc_set_field(0, 33, 33, 1);
 	if (is_store)
-		to_book3s(vcpu)->dsisr = kvmppc_set_field(dsisr, 38, 38, 1);
+		shared->dsisr = kvmppc_set_field(dsisr, 38, 38, 1);
 	kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_DATA_STORAGE);
 }