Re: [PATCH v5 05/23] irqchip/gic-v4.1: Ensure mutual exclusion betwen invalidations on the same RD

Zenghui Yu
2020-03-12T07:12:03Z

On 2020/3/5 4:33, Marc Zyngier wrote:
> The GICv4.1 spec says that it is CONTRAINED UNPREDICTABLE to write to

s/CONTRAINED/CONSTRAINED/

> any of the GICR_INV{LPI,ALL}R registers if GICR_SYNCR.Busy == 1.
>
> To deal with it, we must ensure that only a single invalidation can
> happen at a time for a given redistributor. Add a per-RD lock to that
> effect and take it around the invalidation/syncr-read to deal with this.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>

Thanks

> ---
> drivers/irqchip/irq-gic-v3-its.c | 6 ++++++
> drivers/irqchip/irq-gic-v3.c | 1 +
> include/linux/irqchip/arm-gic-v3.h | 1 +
> 3 files changed, 8 insertions(+)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index c84370245bea..fc5788584df7 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -1373,10 +1373,12 @@ static void direct_lpi_inv(struct irq_data *d)
>
> /* Target the redistributor this LPI is currently routed to */
> cpu = irq_to_cpuid_lock(d, &flags);
> + raw_spin_lock(&gic_data_rdist_cpu(cpu)->rd_lock);
> rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
> gic_write_lpir(val, rdbase + GICR_INVLPIR);
>
> wait_for_syncr(rdbase);
> + raw_spin_unlock(&gic_data_rdist_cpu(cpu)->rd_lock);
> irq_to_cpuid_unlock(d, flags);
> }
>
> @@ -3662,9 +3664,11 @@ static void its_vpe_send_inv(struct irq_data *d)
> void __iomem *rdbase;
>
> /* Target the redistributor this VPE is currently known on */
> + raw_spin_lock(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock);
> rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
> gic_write_lpir(d->parent_data->hwirq, rdbase + GICR_INVLPIR);
> wait_for_syncr(rdbase);
> + raw_spin_unlock(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock);
> } else {
> its_vpe_send_cmd(vpe, its_send_inv);
> }
> @@ -3825,10 +3829,12 @@ static void its_vpe_4_1_invall(struct its_vpe *vpe)
> val |= FIELD_PREP(GICR_INVALLR_VPEID, vpe->vpe_id);
>
> /* Target the redistributor this vPE is currently known on */
> + raw_spin_lock(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock);
> rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
> gic_write_lpir(val, rdbase + GICR_INVALLR);
>
> wait_for_syncr(rdbase);
> + raw_spin_unlock(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock);
> }
>
> static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> index 73e87e176d76..ba405becab53 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -835,6 +835,7 @@ static int __gic_populate_rdist(struct redist_region *region, void __iomem *ptr)
> typer = gic_read_typer(ptr + GICR_TYPER);
> if ((typer >> 32) == aff) {
> u64 offset = ptr - region->redist_base;
> + raw_spin_lock_init(&gic_data_rdist()->rd_lock);
> gic_data_rdist_rd_base() = ptr;
> gic_data_rdist()->phys_base = region->phys_base + offset;
>
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index c29a02678a6f..b28acfa71f82 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -652,6 +652,7 @@
>
> struct rdists {
> struct {
> + raw_spinlock_t rd_lock;
> void __iomem *rd_base;
> struct page *pend_page;
> phys_addr_t phys_base;
>