KVM: PPC: Implement Paired Single emulation

The one big thing about the Gekko is paired singles.

Paired singles are an extension to the instruction set, that adds 32 single
precision floating point registers (qprs), some SPRs to modify the behavior
of paired singled operations and instructions to deal with qprs to the
instruction set.

Unfortunately, it also changes semantics of existing operations that affect
single values in FPRs. In most cases they get mirrored to the coresponding
QPR.

Thanks to that we need to emulate all FPU operations and all the new paired
single operations too.

In order to achieve that, we use the just introduced FPU call helpers to
call the real FPU whenever the guest wants to modify an FPR. Additionally
we also fix up the QPR values along the way.

That way we can execute paired single FPU operations without implementing a
soft fpu.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/include/asm/kvm_book3s.h

@@ -121,6 +121,7 @@ extern void kvmppc_book3s_queue_irqprio(struct kvm_vcpu *vcpu, unsigned int vec)
 extern void kvmppc_set_bat(struct kvm_vcpu *vcpu, struct kvmppc_bat *bat,
 			   bool upper, u32 val);
 extern void kvmppc_giveup_ext(struct kvm_vcpu *vcpu, ulong msr);
+extern int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu);
 
 extern u32 kvmppc_trampoline_lowmem;
 extern u32 kvmppc_trampoline_enter;

arch/powerpc/kvm/Makefile

@@ -41,6 +41,7 @@ kvm-objs-$(CONFIG_KVM_E500) := $(kvm-e500-objs)
 kvm-book3s_64-objs := \
 	$(common-objs-y) \
 	fpu.o \
+	book3s_paired_singles.o \
 	book3s.o \
 	book3s_64_emulate.o \
 	book3s_64_interrupts.o \

arch/powerpc/kvm/book3s_64_emulate.c

@@ -200,6 +200,9 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		emulated = EMULATE_FAIL;
 	}
 
+	if (emulated == EMULATE_FAIL)
+		emulated = kvmppc_emulate_paired_single(run, vcpu);
+
 	return emulated;
 }