Messages in this thread | | | Date | Fri, 17 Jul 2020 12:07:56 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH] irqchip/gic-v4.1: Ensure accessing the correct RD when writing INVALLR |
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On Thu, 09 Jul 2020 14:49:59 +0100, Zenghui Yu <yuzenghui@huawei.com> wrote: > > The GICv4.1 spec tells us that it's CONSTRAINED UNPREDICTABLE to issue a > register-based invalidation operation for a vPEID not mapped to that RD, > or another RD within the same CommonLPIAff group. > > To follow this rule, commit f3a059219bc7 ("irqchip/gic-v4.1: Ensure mutual > exclusion between vPE affinity change and RD access") tried to address the > race between the RD accesses and the vPE affinity change, but somehow > forgot to take GICR_INVALLR into account. Let's take the vpe_lock before > evaluating vpe->col_idx to fix it. > > Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Shouldn't this deserve a Fixes: tag?
Thanks,
M.
> --- > drivers/irqchip/irq-gic-v3-its.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index da44bfa48bc2..50a04cca8207 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -4087,18 +4087,22 @@ 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; > + int cpu; > > 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(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock); > - rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base; > + cpu = vpe_to_cpuid_lock(vpe, &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_INVALLR); > > wait_for_syncr(rdbase); > - raw_spin_unlock(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock); > + raw_spin_unlock(&gic_data_rdist_cpu(cpu)->rd_lock); > + vpe_to_cpuid_unlock(vpe, flags); > } > > static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void *vcpu_info) > -- > 2.19.1 > >
-- Without deviation from the norm, progress is not possible.
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