irqchip/gic-v4.1: Add VPE eviction callback

When descheduling a VPE, special care must be taken to tell the GIC
about whether we want to receive a doorbell or not. This is a
major improvement on GICv4.0, where the doorbell had to be separately
enabled/disabled.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20191224111055.11836-13-maz@kernel.org

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 3adc597e2a82be79036d7c222368fc4f43bb8251..69b16e5da383c5db6ae05d152b4a1c318e751b51 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2630,7 +2630,7 @@ static int __init allocate_lpi_tables(void)
        return 0;
 }
 
-static u64 its_clear_vpend_valid(void __iomem *vlpi_base)
+static u64 its_clear_vpend_valid(void __iomem *vlpi_base, u64 clr, u64 set)
 {
        u32 count = 1000000;    /* 1s! */
        bool clean;
@@ -2638,6 +2638,8 @@ static u64 its_clear_vpend_valid(void __iomem *vlpi_base)
 
        val = gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER);
        val &= ~GICR_VPENDBASER_Valid;
+       val &= ~clr;
+       val |= set;
        gits_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER);
 
        do {
@@ -2650,6 +2652,11 @@ static u64 its_clear_vpend_valid(void __iomem *vlpi_base)
                }
        } while (!clean && count);
 
+       if (unlikely(val & GICR_VPENDBASER_Dirty)) {
+               pr_err_ratelimited("ITS virtual pending table not cleaning\n");
+               val |= GICR_VPENDBASER_PendingLast;
+       }
+
        return val;
 }
 
@@ -2758,7 +2765,7 @@ static void its_cpu_init_lpis(void)
                 * ancient programming gets left in and has possibility of
                 * corrupting memory.
                 */
-               val = its_clear_vpend_valid(vlpi_base);
+               val = its_clear_vpend_valid(vlpi_base, 0, 0);
                WARN_ON(val & GICR_VPENDBASER_Dirty);
        }
 
@@ -3438,16 +3445,10 @@ static void its_vpe_deschedule(struct its_vpe *vpe)
        void __iomem *vlpi_base = gic_data_rdist_vlpi_base();
        u64 val;
 
-       val = its_clear_vpend_valid(vlpi_base);
+       val = its_clear_vpend_valid(vlpi_base, 0, 0);
 
-       if (unlikely(val & GICR_VPENDBASER_Dirty)) {
-               pr_err_ratelimited("ITS virtual pending table not cleaning\n");
-               vpe->idai = false;
-               vpe->pending_last = true;
-       } else {
-               vpe->idai = !!(val & GICR_VPENDBASER_IDAI);
-               vpe->pending_last = !!(val & GICR_VPENDBASER_PendingLast);
-       }
+       vpe->idai = !!(val & GICR_VPENDBASER_IDAI);
+       vpe->pending_last = !!(val & GICR_VPENDBASER_PendingLast);
 }
 
 static void its_vpe_invall(struct its_vpe *vpe)
@@ -3639,6 +3640,35 @@ static void its_vpe_4_1_schedule(struct its_vpe *vpe,
        gits_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER);
 }
 
+static void its_vpe_4_1_deschedule(struct its_vpe *vpe,
+                                  struct its_cmd_info *info)
+{
+       void __iomem *vlpi_base = gic_data_rdist_vlpi_base();
+       u64 val;
+
+       if (info->req_db) {
+               /*
+                * vPE is going to block: make the vPE non-resident with
+                * PendingLast clear and DB set. The GIC guarantees that if
+                * we read-back PendingLast clear, then a doorbell will be
+                * delivered when an interrupt comes.
+                */
+               val = its_clear_vpend_valid(vlpi_base,
+                                           GICR_VPENDBASER_PendingLast,
+                                           GICR_VPENDBASER_4_1_DB);
+               vpe->pending_last = !!(val & GICR_VPENDBASER_PendingLast);
+       } else {
+               /*
+                * We're not blocking, so just make the vPE non-resident
+                * with PendingLast set, indicating that we'll be back.
+                */
+               val = its_clear_vpend_valid(vlpi_base,
+                                           0,
+                                           GICR_VPENDBASER_PendingLast);
+               vpe->pending_last = true;
+       }
+}
+
 static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
 {
        struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
@@ -3650,6 +3680,7 @@ static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
                return 0;
 
        case DESCHEDULE_VPE:
+               its_vpe_4_1_deschedule(vpe, info);
                return 0;
 
        case INVALL_VPE: