KVM: PPC: Read out syscall instruction on trap

We have a few traps where we cache the instruction that cause the trap
for analysis later on. Since we now need to be able to distinguish
between SC 0 and SC 1 system calls and the only way to find out which
is which is by looking at the instruction, we also read out the instruction
causing the system call.
Signed-off-by: NAlexander Graf <agraf@suse.de>

arch/powerpc/kvm/book3s_segment.S

@@ -213,11 +213,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
 	beq	ld_last_inst
 	cmpwi	r12, BOOK3S_INTERRUPT_PROGRAM
 	beq	ld_last_inst
+	cmpwi	r12, BOOK3S_INTERRUPT_SYSCALL
+	beq	ld_last_prev_inst
 	cmpwi	r12, BOOK3S_INTERRUPT_ALIGNMENT
 	beq-	ld_last_inst
 
 	b	no_ld_last_inst
 
+ld_last_prev_inst:
+	addi	r3, r3, -4
+
 ld_last_inst:
 	/* Save off the guest instruction we're at */