irqchip/gic-v4.1: Implement the v4.1 flavour of VMAPP

The ITS VMAPP command gains some new fields with GICv4.1:
- a default doorbell, which allows a single doorbell to be used for
  all the VLPIs routed to a given VPE
- a pointer to the configuration table (instead of having it in a register
  that gets context switched)
- a flag indicating whether this is the first map or the last unmap for
  this particular VPE
- a flag indicating whether the pending table is known to be zeroed, or not

Plumb in the new fields in the VMAPP builder, and add the map/unmap
refcounting so that the ITS can do the right thing.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20191224111055.11836-7-maz@kernel.org

Author: Marc Zyngier

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

@@ -449,6 +449,27 @@ static void its_encode_vpt_size(struct its_cmd_block *cmd, u8 vpt_size)
 	its_mask_encode(&cmd->raw_cmd[3], vpt_size, 4, 0);
 }
 
+static void its_encode_vconf_addr(struct its_cmd_block *cmd, u64 vconf_pa)
+{
+	its_mask_encode(&cmd->raw_cmd[0], vconf_pa >> 16, 51, 16);
+}
+
+static void its_encode_alloc(struct its_cmd_block *cmd, bool alloc)
+{
+	its_mask_encode(&cmd->raw_cmd[0], alloc, 8, 8);
+}
+
+static void its_encode_ptz(struct its_cmd_block *cmd, bool ptz)
+{
+	its_mask_encode(&cmd->raw_cmd[0], ptz, 9, 9);
+}
+
+static void its_encode_vmapp_default_db(struct its_cmd_block *cmd,
+					u32 vpe_db_lpi)
+{
+	its_mask_encode(&cmd->raw_cmd[1], vpe_db_lpi, 31, 0);
+}
+
 static inline void its_fixup_cmd(struct its_cmd_block *cmd)
 {
 	/* Let's fixup BE commands */
@@ -632,19 +653,45 @@ static struct its_vpe *its_build_vmapp_cmd(struct its_node *its,
 					   struct its_cmd_block *cmd,
 					   struct its_cmd_desc *desc)
 {
-	unsigned long vpt_addr;
+	unsigned long vpt_addr, vconf_addr;
 	u64 target;
-
-	vpt_addr = virt_to_phys(page_address(desc->its_vmapp_cmd.vpe->vpt_page));
-	target = desc->its_vmapp_cmd.col->target_address + its->vlpi_redist_offset;
+	bool alloc;
 
 	its_encode_cmd(cmd, GITS_CMD_VMAPP);
 	its_encode_vpeid(cmd, desc->its_vmapp_cmd.vpe->vpe_id);
 	its_encode_valid(cmd, desc->its_vmapp_cmd.valid);
+
+	if (!desc->its_vmapp_cmd.valid) {
+		if (is_v4_1(its)) {
+			alloc = !atomic_dec_return(&desc->its_vmapp_cmd.vpe->vmapp_count);
+			its_encode_alloc(cmd, alloc);
+		}
+
+		goto out;
+	}
+
+	vpt_addr = virt_to_phys(page_address(desc->its_vmapp_cmd.vpe->vpt_page));
+	target = desc->its_vmapp_cmd.col->target_address + its->vlpi_redist_offset;
+
 	its_encode_target(cmd, target);
 	its_encode_vpt_addr(cmd, vpt_addr);
 	its_encode_vpt_size(cmd, LPI_NRBITS - 1);
 
+	if (!is_v4_1(its))
+		goto out;
+
+	vconf_addr = virt_to_phys(page_address(desc->its_vmapp_cmd.vpe->its_vm->vprop_page));
+
+	alloc = !atomic_fetch_inc(&desc->its_vmapp_cmd.vpe->vmapp_count);
+
+	its_encode_alloc(cmd, alloc);
+
+	/* We can only signal PTZ when alloc==1. Why do we have two bits? */
+	its_encode_ptz(cmd, alloc);
+	its_encode_vconf_addr(cmd, vconf_addr);
+	its_encode_vmapp_default_db(cmd, desc->its_vmapp_cmd.vpe->vpe_db_lpi);
+
+out:
 	its_fixup_cmd(cmd);
 
 	return valid_vpe(its, desc->its_vmapp_cmd.vpe);
@@ -3492,7 +3539,10 @@ static int its_vpe_init(struct its_vpe *vpe)
 
 	vpe->vpe_id = vpe_id;
 	vpe->vpt_page = vpt_page;
-	vpe->vpe_proxy_event = -1;
+	if (gic_rdists->has_rvpeid)
+		atomic_set(&vpe->vmapp_count, 0);
+	else
+		vpe->vpe_proxy_event = -1;
 
 	return 0;
 }

include/linux/irqchip/arm-gic-v4.h

@@ -39,8 +39,20 @@ struct its_vpe {
 	irq_hw_number_t		vpe_db_lpi;
 	/* VPE resident */
 	bool			resident;
-	/* VPE proxy mapping */
-	int			vpe_proxy_event;
+	union {
+		/* GICv4.0 implementations */
+		struct {
+			/* VPE proxy mapping */
+			int	vpe_proxy_event;
+			/* Implementation Defined Area Invalid */
+			bool	idai;
+		};
+		/* GICv4.1 implementations */
+		struct {
+			atomic_t vmapp_count;
+		};
+	};
+
 	/*
 	 * This collection ID is used to indirect the target
 	 * redistributor for this VPE. The ID itself isn't involved in
@@ -49,8 +61,6 @@ struct its_vpe {
 	u16			col_idx;
 	/* Unique (system-wide) VPE identifier */
 	u16			vpe_id;
-	/* Implementation Defined Area Invalid */
-	bool			idai;
 	/* Pending VLPIs on schedule out? */
 	bool			pending_last;
 };