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Date: Thu, 20 Feb 2020 11:11:46 +0800
From: Zenghui Yu <yuzenghui@...wei.com>
To: Marc Zyngier <maz@...nel.org>
CC: <linux-arm-kernel@...ts.infradead.org>,
<kvmarm@...ts.cs.columbia.edu>, <kvm@...r.kernel.org>,
<linux-kernel@...r.kernel.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Jason Cooper <jason@...edaemon.net>,
"Robert Richter" <rrichter@...vell.com>,
Thomas Gleixner <tglx@...utronix.de>,
"Eric Auger" <eric.auger@...hat.com>,
James Morse <james.morse@....com>,
"Julien Thierry" <julien.thierry.kdev@...il.com>,
Suzuki K Poulose <suzuki.poulose@....com>
Subject: Re: [PATCH v4 08/20] irqchip/gic-v4.1: Plumb get/set_irqchip_state
SGI callbacks
Hi Marc,
On 2020/2/18 23:31, Marc Zyngier wrote:
> diff --git a/drivers/irqchip/irq-gic-v3-its.c
> b/drivers/irqchip/irq-gic-v3-its.c
> index 7656b353a95f..0ed286dba827 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -144,7 +144,7 @@ struct event_lpi_map {
> u16 *col_map;
> irq_hw_number_t lpi_base;
> int nr_lpis;
> - raw_spinlock_t vlpi_lock;
> + raw_spinlock_t map_lock;
So we use map_lock to protect both LPI's and VLPI's mapping affinity of
a device, and use vpe_lock to protect vPE's affinity, OK.
> struct its_vm *vm;
> struct its_vlpi_map *vlpi_maps;
> int nr_vlpis;
> @@ -240,15 +240,33 @@ static struct its_vlpi_map *get_vlpi_map(struct
> irq_data *d)
> return NULL;
> }
>
> -static int irq_to_cpuid(struct irq_data *d)
> +static int irq_to_cpuid_lock(struct irq_data *d, unsigned long *flags)
> {
> - struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> struct its_vlpi_map *map = get_vlpi_map(d);
> + int cpu;
>
> - if (map)
> - return map->vpe->col_idx;
> + if (map) {
> + raw_spin_lock_irqsave(&map->vpe->vpe_lock, *flags);
> + cpu = map->vpe->col_idx;
> + } else {
> + struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> + raw_spin_lock_irqsave(&its_dev->event_map.map_lock, *flags);
> + cpu = its_dev->event_map.col_map[its_get_event_id(d)];
> + }
>
> - return its_dev->event_map.col_map[its_get_event_id(d)];
> + return cpu;
> +}
This helper is correct for normal LPIs and VLPIs, but wrong for per-vPE
IRQ (doorbell) and vSGIs. irq_data_get_irq_chip_data() gets confused by
both of them.
> +
> +static void irq_to_cpuid_unlock(struct irq_data *d, unsigned long flags)
> +{
> + struct its_vlpi_map *map = get_vlpi_map(d);
> +
> + if (map) {
> + raw_spin_unlock_irqrestore(&map->vpe->vpe_lock, flags);
> + } else {
> + struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> + raw_spin_unlock_irqrestore(&its_dev->event_map.map_lock, flags);
> + }
> }
The same problem for this helper.
>
> static struct its_collection *valid_col(struct its_collection *col)
> @@ -1384,6 +1402,8 @@ static void direct_lpi_inv(struct irq_data *d)
> {
> struct its_vlpi_map *map = get_vlpi_map(d);
> void __iomem *rdbase;
> + unsigned long flags;
> + int cpu;
> u64 val;
>
> if (map) {
> @@ -1399,10 +1419,12 @@ static void direct_lpi_inv(struct irq_data *d)
> }
>
> /* Target the redistributor this LPI is currently routed to */
> - rdbase = per_cpu_ptr(gic_rdists->rdist, irq_to_cpuid(d))->rd_base;
> + cpu = irq_to_cpuid_lock(d, &flags);
> + rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
> gic_write_lpir(val, rdbase + GICR_INVLPIR);
>
> wait_for_syncr(rdbase);
> + irq_to_cpuid_unlock(d, flags);
> }
>
> static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
> @@ -1471,11 +1493,11 @@ static void its_unmask_irq(struct irq_data *d)
> static int its_set_affinity(struct irq_data *d, const struct cpumask
> *mask_val,
> bool force)
> {
> - unsigned int cpu;
> const struct cpumask *cpu_mask = cpu_online_mask;
> struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> struct its_collection *target_col;
> - u32 id = its_get_event_id(d);
> + unsigned int from, cpu;
> + unsigned long flags;
>
> /* A forwarded interrupt should use irq_set_vcpu_affinity */
> if (irqd_is_forwarded_to_vcpu(d))
> @@ -1496,12 +1518,16 @@ static int its_set_affinity(struct irq_data *d,
> const struct cpumask *mask_val,
> return -EINVAL;
>
> /* don't set the affinity when the target cpu is same as current
> one */
> - if (cpu != its_dev->event_map.col_map[id]) {
> + from = irq_to_cpuid_lock(d, &flags);
> + if (cpu != from) {
> + u32 id = its_get_event_id(d);
> +
> target_col = &its_dev->its->collections[cpu];
> its_send_movi(its_dev, target_col, id);
> its_dev->event_map.col_map[id] = cpu;
> irq_data_update_effective_affinity(d, cpumask_of(cpu));
> }
> + irq_to_cpuid_unlock(d, flags);
>
> return IRQ_SET_MASK_OK_DONE;
> }
> @@ -1636,7 +1662,7 @@ static int its_vlpi_map(struct irq_data *d, struct
> its_cmd_info *info)
> if (!info->map)
> return -EINVAL;
>
> - raw_spin_lock(&its_dev->event_map.vlpi_lock);
> + raw_spin_lock(&its_dev->event_map.map_lock);
>
> if (!its_dev->event_map.vm) {
> struct its_vlpi_map *maps;
> @@ -1685,7 +1711,7 @@ static int its_vlpi_map(struct irq_data *d, struct
> its_cmd_info *info)
> }
>
> out:
> - raw_spin_unlock(&its_dev->event_map.vlpi_lock);
> + raw_spin_unlock(&its_dev->event_map.map_lock);
> return ret;
> }
>
> @@ -1695,7 +1721,7 @@ static int its_vlpi_get(struct irq_data *d, struct
> its_cmd_info *info)
> struct its_vlpi_map *map;
> int ret = 0;
>
> - raw_spin_lock(&its_dev->event_map.vlpi_lock);
> + raw_spin_lock(&its_dev->event_map.map_lock);
>
> map = get_vlpi_map(d);
>
> @@ -1708,7 +1734,7 @@ static int its_vlpi_get(struct irq_data *d, struct
> its_cmd_info *info)
> *info->map = *map;
>
> out:
> - raw_spin_unlock(&its_dev->event_map.vlpi_lock);
> + raw_spin_unlock(&its_dev->event_map.map_lock);
> return ret;
> }
>
> @@ -1718,7 +1744,7 @@ static int its_vlpi_unmap(struct irq_data *d)
> u32 event = its_get_event_id(d);
> int ret = 0;
>
> - raw_spin_lock(&its_dev->event_map.vlpi_lock);
> + raw_spin_lock(&its_dev->event_map.map_lock);
>
> if (!its_dev->event_map.vm || !irqd_is_forwarded_to_vcpu(d)) {
> ret = -EINVAL;
> @@ -1748,7 +1774,7 @@ static int its_vlpi_unmap(struct irq_data *d)
> }
>
> out:
> - raw_spin_unlock(&its_dev->event_map.vlpi_lock);
> + raw_spin_unlock(&its_dev->event_map.map_lock);
> return ret;
> }
>
> @@ -3193,7 +3219,7 @@ static struct its_device *its_create_device(struct
> its_node *its, u32 dev_id,
> dev->event_map.col_map = col_map;
> dev->event_map.lpi_base = lpi_base;
> dev->event_map.nr_lpis = nr_lpis;
> - raw_spin_lock_init(&dev->event_map.vlpi_lock);
> + raw_spin_lock_init(&dev->event_map.map_lock);
> dev->device_id = dev_id;
> INIT_LIST_HEAD(&dev->entry);
>
> @@ -3560,6 +3586,7 @@ static int its_vpe_set_affinity(struct irq_data *d,
> {
> struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
> int from, cpu = cpumask_first(mask_val);
> + unsigned long flags;
>
> /*
> * Changing affinity is mega expensive, so let's be as lazy as
> @@ -3567,6 +3594,7 @@ 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.
> */
> + raw_spin_lock_irqsave(&vpe->vpe_lock, flags);
> if (vpe->col_idx == cpu)
> goto out;
>
> @@ -3586,6 +3614,7 @@ static int its_vpe_set_affinity(struct irq_data *d,
>
> out:
> irq_data_update_effective_affinity(d, cpumask_of(cpu));
> + raw_spin_unlock_irqrestore(&vpe->vpe_lock, flags);
>
> return IRQ_SET_MASK_OK_DONE;
> }
> @@ -3695,11 +3724,15 @@ static void its_vpe_send_inv(struct irq_data *d)
>
> if (gic_rdists->has_direct_lpi) {
> void __iomem *rdbase;
> + unsigned long flags;
> + int cpu;
>
> /* Target the redistributor this VPE is currently known on */
> - rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
> + cpu = irq_to_cpuid_lock(d, &flags);
> + rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
> gic_write_lpir(d->parent_data->hwirq, rdbase + GICR_INVLPIR);
> wait_for_syncr(rdbase);
> + irq_to_cpuid_unlock(d, flags);
> } else {
> its_vpe_send_cmd(vpe, its_send_inv);
> }
Do we really need to grab the vpe_lock for those which are belong to
the same irqchip with its_vpe_set_affinity()? The IRQ core code should
already ensure the mutual exclusion among them, wrong?
> @@ -3735,14 +3768,18 @@ static int its_vpe_set_irqchip_state(struct
> irq_data *d,
>
> if (gic_rdists->has_direct_lpi) {
> void __iomem *rdbase;
> + unsigned long flags;
> + int cpu;
>
> - rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
> + cpu = irq_to_cpuid_lock(d, &flags);
> + rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
> if (state) {
> gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_SETLPIR);
> } else {
> gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_CLRLPIR);
> wait_for_syncr(rdbase);
> }
> + irq_to_cpuid_unlock(d, flags);
> } else {
> if (state)
> its_vpe_send_cmd(vpe, its_send_int);
> @@ -3854,14 +3891,17 @@ static void its_vpe_4_1_deschedule(struct
> its_vpe *vpe,
> static void its_vpe_4_1_invall(struct its_vpe *vpe)
> {
> void __iomem *rdbase;
> + unsigned long flags;
> u64 val;
>
> val = GICR_INVALLR_V;
> val |= FIELD_PREP(GICR_INVALLR_VPEID, vpe->vpe_id);
>
> /* Target the redistributor this vPE is currently known on */
> + raw_spin_lock_irqsave(&vpe->vpe_lock, flags);
> rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
> gic_write_lpir(val, rdbase + GICR_INVALLR);
> + raw_spin_unlock_irqrestore(&vpe->vpe_lock, flags);
> }
>
> static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void
> *vcpu_info)
> @@ -3960,13 +4000,17 @@ static int its_sgi_get_irqchip_state(struct
> irq_data *d,
> enum irqchip_irq_state which, bool *val)
> {
> struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
> - void __iomem *base = gic_data_rdist_cpu(vpe->col_idx)->rd_base +
> SZ_128K;
> + void __iomem *base;
> + unsigned long flags;
> u32 count = 1000000; /* 1s! */
> u32 status;
> + int cpu;
>
> if (which != IRQCHIP_STATE_PENDING)
> return -EINVAL;
>
> + cpu = irq_to_cpuid_lock(d, &flags);
> + base = gic_data_rdist_cpu(cpu)->rd_base + SZ_128K;
> writel_relaxed(vpe->vpe_id, base + GICR_VSGIR);
> do {
> status = readl_relaxed(base + GICR_VSGIPENDR);
> @@ -3983,6 +4027,7 @@ static int its_sgi_get_irqchip_state(struct
> irq_data *d,
> } while(count);
>
> out:
> + irq_to_cpuid_unlock(d, flags);
> *val = !!(status & (1 << d->hwirq));
>
> return 0;
> @@ -4102,6 +4147,7 @@ static int its_vpe_init(struct its_vpe *vpe)
> return -ENOMEM;
> }
>
> + raw_spin_lock_init(&vpe->vpe_lock);
> vpe->vpe_id = vpe_id;
> vpe->vpt_page = vpt_page;
> if (gic_rdists->has_rvpeid)
> diff --git a/include/linux/irqchip/arm-gic-v4.h
> b/include/linux/irqchip/arm-gic-v4.h
> index 46c167a6349f..fc43a63875a3 100644
> --- a/include/linux/irqchip/arm-gic-v4.h
> +++ b/include/linux/irqchip/arm-gic-v4.h
> @@ -60,6 +60,7 @@ struct its_vpe {
> };
> };
>
> + raw_spinlock_t vpe_lock;
> /*
> * This collection ID is used to indirect the target
> * redistributor for this VPE. The ID itself isn't involved in
I'm not sure if it's good enough, it may gets much clearer after
splitting.
Thanks,
Zenghui
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