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 <[e-mail]>
Signed-off-by: Avi Kivity <[e-mail]>

arch/powerpc/include/asm/kvm_book3s.h

···
 	u64 hid[6];
 	u64 gqr[8];
 	int slb_nr;
-	u32 dsisr;
 	u64 sdr1;
 	u64 hior;
 	u64 msr_mask;

arch/powerpc/include/asm/kvm_para.h

···
 
 struct kvm_vcpu_arch_shared {
 	__u64 msr;
+	__u32 dsisr;
 };
 
 #ifdef __KERNEL__

arch/powerpc/kvm/book3s.c

···
 	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);
···
 			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;
···
 	}
 	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));

arch/powerpc/kvm/book3s_emulate.c

···
 				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,
···
 		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;
···
 		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);

arch/powerpc/kvm/book3s_paired_singles.c

···
 	/* 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);
 }