irqchip/gic-v3-its: Add VPE affinity changes

When we're about to run a vcpu, it is crucial that the redistributor
associated with the physical CPU is being told about the new residency.

This is abstracted by hijacking the irq_set_affinity method for the
doorbell interrupt associated with the VPE. It is expected that the
hypervisor will call this method before scheduling the VPE.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 21b728df7544a4bc5fb24a4fa9587438832cb73f..ab25b57866cd19a51c494047f4ffabcf6fcad128 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -148,6 +148,9 @@ static struct irq_domain *its_parent;
 #define ITS_LIST_MAX           16
 
 static unsigned long its_list_map;
+static u16 vmovp_seq_num;
+static DEFINE_RAW_SPINLOCK(vmovp_lock);
+
 static DEFINE_IDA(its_vpeid_ida);
 
 #define gic_data_rdist()               (raw_cpu_ptr(gic_rdists->rdist))
@@ -238,6 +241,13 @@ struct its_cmd_desc {
                        u32 event_id;
                        bool db_enabled;
                } its_vmovi_cmd;
+
+               struct {
+                       struct its_vpe *vpe;
+                       struct its_collection *col;
+                       u16 seq_num;
+                       u16 its_list;
+               } its_vmovp_cmd;
        };
 };
 
@@ -329,6 +339,16 @@ static void its_encode_db_valid(struct its_cmd_block *cmd, bool db_valid)
        its_mask_encode(&cmd->raw_cmd[2], db_valid, 0, 0);
 }
 
+static void its_encode_seq_num(struct its_cmd_block *cmd, u16 seq_num)
+{
+       its_mask_encode(&cmd->raw_cmd[0], seq_num, 47, 32);
+}
+
+static void its_encode_its_list(struct its_cmd_block *cmd, u16 its_list)
+{
+       its_mask_encode(&cmd->raw_cmd[1], its_list, 15, 0);
+}
+
 static void its_encode_vpt_addr(struct its_cmd_block *cmd, u64 vpt_pa)
 {
        its_mask_encode(&cmd->raw_cmd[3], vpt_pa >> 16, 50, 16);
@@ -571,6 +591,20 @@ static struct its_vpe *its_build_vmovi_cmd(struct its_cmd_block *cmd,
        return desc->its_vmovi_cmd.vpe;
 }
 
+static struct its_vpe *its_build_vmovp_cmd(struct its_cmd_block *cmd,
+                                          struct its_cmd_desc *desc)
+{
+       its_encode_cmd(cmd, GITS_CMD_VMOVP);
+       its_encode_seq_num(cmd, desc->its_vmovp_cmd.seq_num);
+       its_encode_its_list(cmd, desc->its_vmovp_cmd.its_list);
+       its_encode_vpeid(cmd, desc->its_vmovp_cmd.vpe->vpe_id);
+       its_encode_target(cmd, desc->its_vmovp_cmd.col->target_address);
+
+       its_fixup_cmd(cmd);
+
+       return desc->its_vmovp_cmd.vpe;
+}
+
 static u64 its_cmd_ptr_to_offset(struct its_node *its,
                                 struct its_cmd_block *ptr)
 {
@@ -871,6 +905,48 @@ static void its_send_vmapp(struct its_vpe *vpe, bool valid)
        }
 }
 
+static void its_send_vmovp(struct its_vpe *vpe)
+{
+       struct its_cmd_desc desc;
+       struct its_node *its;
+       unsigned long flags;
+       int col_id = vpe->col_idx;
+
+       desc.its_vmovp_cmd.vpe = vpe;
+       desc.its_vmovp_cmd.its_list = (u16)its_list_map;
+
+       if (!its_list_map) {
+               its = list_first_entry(&its_nodes, struct its_node, entry);
+               desc.its_vmovp_cmd.seq_num = 0;
+               desc.its_vmovp_cmd.col = &its->collections[col_id];
+               its_send_single_vcommand(its, its_build_vmovp_cmd, &desc);
+               return;
+       }
+
+       /*
+        * Yet another marvel of the architecture. If using the
+        * its_list "feature", we need to make sure that all ITSs
+        * receive all VMOVP commands in the same order. The only way
+        * to guarantee this is to make vmovp a serialization point.
+        *
+        * Wall <-- Head.
+        */
+       raw_spin_lock_irqsave(&vmovp_lock, flags);
+
+       desc.its_vmovp_cmd.seq_num = vmovp_seq_num++;
+
+       /* Emit VMOVPs */
+       list_for_each_entry(its, &its_nodes, entry) {
+               if (!its->is_v4)
+                       continue;
+
+               desc.its_vmovp_cmd.col = &its->collections[col_id];
+               its_send_single_vcommand(its, its_build_vmovp_cmd, &desc);
+       }
+
+       raw_spin_unlock_irqrestore(&vmovp_lock, flags);
+}
+
 static void its_send_vinvall(struct its_vpe *vpe)
 {
        struct its_cmd_desc desc;
@@ -2154,6 +2230,25 @@ static const struct irq_domain_ops its_domain_ops = {
        .deactivate             = its_irq_domain_deactivate,
 };
 
+static int its_vpe_set_affinity(struct irq_data *d,
+                               const struct cpumask *mask_val,
+                               bool force)
+{
+       struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
+       int cpu = cpumask_first(mask_val);
+
+       /*
+        * Changing affinity is mega expensive, so let's be as lazy as
+        * we can and only do it if we really have to.
+        */
+       if (vpe->col_idx != cpu) {
+               vpe->col_idx = cpu;
+               its_send_vmovp(vpe);
+       }
+
+       return IRQ_SET_MASK_OK_DONE;
+}
+
 static void its_vpe_schedule(struct its_vpe *vpe)
 {
        void * __iomem vlpi_base = gic_data_rdist_vlpi_base();
@@ -2243,6 +2338,7 @@ static int its_vpe_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
 
 static struct irq_chip its_vpe_irq_chip = {
        .name                   = "GICv4-vpe",
+       .irq_set_affinity       = its_vpe_set_affinity,
        .irq_set_vcpu_affinity  = its_vpe_set_vcpu_affinity,
 };