irqchip/gic-v3-its: Only emit VSYNC if targetting a valid collection

Similarily to the SYNC operation, it must be verified that the VPE
targetted by a VLPI is backed by a valid collection in the GIC driver data
structures.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
Link: https://lkml.kernel.org/r/20180622095254.5906-7-marc.zyngier@arm.com

drivers/irqchip/irq-gic-v3-its.c

@@ -190,6 +190,14 @@ static struct its_collection *valid_col(struct its_collection *col)
 	return col;
 }
 
+static struct its_vpe *valid_vpe(struct its_node *its, struct its_vpe *vpe)
+{
+	if (valid_col(its->collections + vpe->col_idx))
+		return vpe;
+
+	return NULL;
+}
+
 /*
  * ITS command descriptors - parameters to be encoded in a command
  * block.
@@ -562,7 +570,7 @@ static struct its_vpe *its_build_vinvall_cmd(struct its_node *its,
 
 	its_fixup_cmd(cmd);
 
-	return desc->its_vinvall_cmd.vpe;
+	return valid_vpe(its, desc->its_vinvall_cmd.vpe);
 }
 
 static struct its_vpe *its_build_vmapp_cmd(struct its_node *its,
@@ -584,7 +592,7 @@ static struct its_vpe *its_build_vmapp_cmd(struct its_node *its,
 
 	its_fixup_cmd(cmd);
 
-	return desc->its_vmapp_cmd.vpe;
+	return valid_vpe(its, desc->its_vmapp_cmd.vpe);
 }
 
 static struct its_vpe *its_build_vmapti_cmd(struct its_node *its,
@@ -607,7 +615,7 @@ static struct its_vpe *its_build_vmapti_cmd(struct its_node *its,
 
 	its_fixup_cmd(cmd);
 
-	return desc->its_vmapti_cmd.vpe;
+	return valid_vpe(its, desc->its_vmapti_cmd.vpe);
 }
 
 static struct its_vpe *its_build_vmovi_cmd(struct its_node *its,
@@ -630,7 +638,7 @@ static struct its_vpe *its_build_vmovi_cmd(struct its_node *its,
 
 	its_fixup_cmd(cmd);
 
-	return desc->its_vmovi_cmd.vpe;
+	return valid_vpe(its, desc->its_vmovi_cmd.vpe);
 }
 
 static struct its_vpe *its_build_vmovp_cmd(struct its_node *its,
@@ -648,7 +656,7 @@ static struct its_vpe *its_build_vmovp_cmd(struct its_node *its,
 
 	its_fixup_cmd(cmd);
 
-	return desc->its_vmovp_cmd.vpe;
+	return valid_vpe(its, desc->its_vmovp_cmd.vpe);
 }
 
 static u64 its_cmd_ptr_to_offset(struct its_node *its,