[tip: irq/core] irqchip/gic-v4.1: Implement the v4.1 flavour of VMOVP

[tip-bot2 for Marc Zyngier]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     dd3f050a216ef7c8ce21ba48fd3b2ece2155382f
Gitweb:        https://git.kernel.org/tip/dd3f050a216ef7c8ce21ba48fd3b2ece2155382f
Author:        Marc Zyngier <maz@xxxxxxxxxx>
AuthorDate:    Tue, 24 Dec 2019 11:10:31 
Committer:     Marc Zyngier <maz@xxxxxxxxxx>
CommitterDate: Wed, 22 Jan 2020 14:22:20 

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

With GICv4.1, VMOVP is extended to allow a default doorbell to be
specified, as well as a validity bit for this doorbell. As an added
bonus, VMOVP isn't required anymore of moving a VPE between
redistributors that share the same affinity.

Let's add this support to the VMOVP builder, and make sure we don't
issue the command if we don't really need to.

Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20191224111055.11836-9-maz@xxxxxxxxxx
---
 drivers/irqchip/irq-gic-v3-its.c | 40 +++++++++++++++++++++++++------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 9bc8adf..53a7663 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -470,6 +470,17 @@ static void its_encode_vmapp_default_db(struct its_cmd_block *cmd,
 	its_mask_encode(&cmd->raw_cmd[1], vpe_db_lpi, 31, 0);
 }
 
+static void its_encode_vmovp_default_db(struct its_cmd_block *cmd,
+					u32 vpe_db_lpi)
+{
+	its_mask_encode(&cmd->raw_cmd[3], vpe_db_lpi, 31, 0);
+}
+
+static void its_encode_db(struct its_cmd_block *cmd, bool db)
+{
+	its_mask_encode(&cmd->raw_cmd[2], db, 63, 63);
+}
+
 static inline void its_fixup_cmd(struct its_cmd_block *cmd)
 {
 	/* Let's fixup BE commands */
@@ -756,6 +767,11 @@ static struct its_vpe *its_build_vmovp_cmd(struct its_node *its,
 	its_encode_vpeid(cmd, desc->its_vmovp_cmd.vpe->vpe_id);
 	its_encode_target(cmd, target);
 
+	if (is_v4_1(its)) {
+		its_encode_db(cmd, true);
+		its_encode_vmovp_default_db(cmd, desc->its_vmovp_cmd.vpe->vpe_db_lpi);
+	}
+
 	its_fixup_cmd(cmd);
 
 	return valid_vpe(its, desc->its_vmovp_cmd.vpe);
@@ -3327,7 +3343,7 @@ static int its_vpe_set_affinity(struct irq_data *d,
 				bool force)
 {
 	struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
-	int cpu = cpumask_first(mask_val);
+	int from, cpu = cpumask_first(mask_val);
 
 	/*
 	 * Changing affinity is mega expensive, so let's be as lazy as
@@ -3335,14 +3351,24 @@ static int its_vpe_set_affinity(struct irq_data *d,
 	 * into the proxy device, we need to move the doorbell
 	 * interrupt to its new location.
 	 */
-	if (vpe->col_idx != cpu) {
-		int from = vpe->col_idx;
+	if (vpe->col_idx == cpu)
+		goto out;
 
-		vpe->col_idx = cpu;
-		its_send_vmovp(vpe);
-		its_vpe_db_proxy_move(vpe, from, cpu);
-	}
+	from = vpe->col_idx;
+	vpe->col_idx = cpu;
+
+	/*
+	 * GICv4.1 allows us to skip VMOVP if moving to a cpu whose RD
+	 * is sharing its VPE table with the current one.
+	 */
+	if (gic_data_rdist_cpu(cpu)->vpe_table_mask &&
+	    cpumask_test_cpu(from, gic_data_rdist_cpu(cpu)->vpe_table_mask))
+		goto out;
 
+	its_send_vmovp(vpe);
+	its_vpe_db_proxy_move(vpe, from, cpu);
+
+out:
 	irq_data_update_effective_affinity(d, cpumask_of(cpu));
 
 	return IRQ_SET_MASK_OK_DONE;