KVM: arm64: Promote guest ownership for DBGxVR/DBGxCR reads

Only yielding control of the debug registers for writes is a bit silly,
unless of course you're a fan of pointless traps. Give control of the
debug registers to the guest upon the first access, regardless of
direction.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-20-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/kvm/sys_regs.c

@@ -643,8 +643,6 @@ static void reg_to_dbg(struct kvm_vcpu *vcpu,
 	val &= ~mask;
 	val |= (p->regval & (mask >> shift)) << shift;
 	*dbg_reg = val;
-
-	kvm_debug_set_guest_ownership(vcpu);
 }
 
 static void dbg_to_reg(struct kvm_vcpu *vcpu,
@@ -690,6 +688,7 @@ static bool trap_dbg_wb_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	else
 		dbg_to_reg(vcpu, p, rd, reg);
 
+	kvm_debug_set_guest_ownership(vcpu);
 	return true;
 }