| Message ID | 20240705093155.871070-4-maz@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | irqchip/gic-v4: Fix VMAPP/VMOVP races | expand |
On 2024/7/5 17:31, Marc Zyngier wrote: > In order to make sure that vpe->col_idx is correctly sampled > when a VMAPP command is issued, we must hold the lock for the > VPE. This is now possible since the introduction of the per-VM > vmapp_lock, which can be taken before vpe_lock in the locking > order. > > Signed-off-by: Marc Zyngier <maz@kernel.org> > --- > drivers/irqchip/irq-gic-v3-its.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index b52d60097cad5..951ec140bcea2 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -1810,7 +1810,9 @@ static void its_map_vm(struct its_node *its, struct its_vm *vm) > for (i = 0; i < vm->nr_vpes; i++) { > struct its_vpe *vpe = vm->vpes[i]; > > - its_send_vmapp(its, vpe, true); > + scoped_guard(raw_spinlock, &vpe->vpe_lock) > + its_send_vmapp(its, vpe, true); > + > its_send_vinvall(its, vpe); > } > } > @@ -1827,8 +1829,10 @@ static void its_unmap_vm(struct its_node *its, struct its_vm *vm) > if (!--vm->vlpi_count[its->list_nr]) { > int i; > > - for (i = 0; i < vm->nr_vpes; i++) > + for (i = 0; i < vm->nr_vpes; i++) { > + guard(raw_spinlock)(&vm->vpes[i]->vpe_lock); > its_send_vmapp(its, vm->vpes[i], false); > + } > } > } > Hi Marc, It looks like there is ABBA deadlock after applying this series: In its_map_vm: vmapp_lock -> vpe_lock In its_vpe_set_affinity: vpe_to_cpuid_lock(vpe_lock) -> its_send_vmovp(vmapp_lock) Any idea about this? Best, Zhou
On Fri, 19 Jul 2024 10:42:02 +0100, Zhou Wang <wangzhou1@hisilicon.com> wrote: > > On 2024/7/5 17:31, Marc Zyngier wrote: > > In order to make sure that vpe->col_idx is correctly sampled > > when a VMAPP command is issued, we must hold the lock for the > > VPE. This is now possible since the introduction of the per-VM > > vmapp_lock, which can be taken before vpe_lock in the locking > > order. > > > > Signed-off-by: Marc Zyngier <maz@kernel.org> > > --- > > drivers/irqchip/irq-gic-v3-its.c | 8 ++++++-- > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > > index b52d60097cad5..951ec140bcea2 100644 > > --- a/drivers/irqchip/irq-gic-v3-its.c > > +++ b/drivers/irqchip/irq-gic-v3-its.c > > @@ -1810,7 +1810,9 @@ static void its_map_vm(struct its_node *its, struct its_vm *vm) > > for (i = 0; i < vm->nr_vpes; i++) { > > struct its_vpe *vpe = vm->vpes[i]; > > > > - its_send_vmapp(its, vpe, true); > > + scoped_guard(raw_spinlock, &vpe->vpe_lock) > > + its_send_vmapp(its, vpe, true); > > + > > its_send_vinvall(its, vpe); > > } > > } > > @@ -1827,8 +1829,10 @@ static void its_unmap_vm(struct its_node *its, struct its_vm *vm) > > if (!--vm->vlpi_count[its->list_nr]) { > > int i; > > > > - for (i = 0; i < vm->nr_vpes; i++) > > + for (i = 0; i < vm->nr_vpes; i++) { > > + guard(raw_spinlock)(&vm->vpes[i]->vpe_lock); > > its_send_vmapp(its, vm->vpes[i], false); > > + } > > } > > } > > > > Hi Marc, > > It looks like there is ABBA deadlock after applying this series: > > In its_map_vm: vmapp_lock -> vpe_lock > In its_vpe_set_affinity: vpe_to_cpuid_lock(vpe_lock) -> its_send_vmovp(vmapp_lock) > > Any idea about this? Hmmm, well spotted. That's an annoying one. Can you give the below hack a go? I've only lightly tested it, as my D05 box is on its last leg (it is literally falling apart) and I don't have any other GICv4.x box to test on. Thanks, M. diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 951ec140bcea2..b88c6011c8771 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -1328,12 +1328,6 @@ static void its_send_vmovp(struct its_vpe *vpe) return; } - /* - * Protect against concurrent updates of the mapping state on - * individual VMs. - */ - guard(raw_spinlock_irqsave)(&vpe->its_vm->vmapp_lock); - /* * Yet another marvel of the architecture. If using the * its_list "feature", we need to make sure that all ITSs @@ -3808,7 +3802,7 @@ static int its_vpe_set_affinity(struct irq_data *d, struct its_vpe *vpe = irq_data_get_irq_chip_data(d); unsigned int from, cpu = nr_cpu_ids; struct cpumask *table_mask; - unsigned long flags; + unsigned long flags, vmapp_flags; /* * Changing affinity is mega expensive, so let's be as lazy as @@ -3822,7 +3816,14 @@ static int its_vpe_set_affinity(struct irq_data *d, * protect us, and that we must ensure nobody samples vpe->col_idx * during the update, hence the lock below which must also be * taken on any vLPI handling path that evaluates vpe->col_idx. + * + * Finally, we must protect ourselves against concurrent + * updates of the mapping state on this VM should the ITS list + * be in use. */ + if (its_list_map) + raw_spin_lock_irqsave(&vpe->its_vm->vmapp_lock, vmapp_flags); + from = vpe_to_cpuid_lock(vpe, &flags); table_mask = gic_data_rdist_cpu(from)->vpe_table_mask; @@ -3852,6 +3853,9 @@ static int its_vpe_set_affinity(struct irq_data *d, irq_data_update_effective_affinity(d, cpumask_of(cpu)); vpe_to_cpuid_unlock(vpe, flags); + if (its_list_map) + raw_spin_unlock_irqrestore(&vpe->its_vm->vmapp_lock, vmapp_flags); + return IRQ_SET_MASK_OK_DONE; }
On 2024/7/19 19:31, Marc Zyngier wrote: > On Fri, 19 Jul 2024 10:42:02 +0100, > Zhou Wang <wangzhou1@hisilicon.com> wrote: >> >> On 2024/7/5 17:31, Marc Zyngier wrote: >>> In order to make sure that vpe->col_idx is correctly sampled >>> when a VMAPP command is issued, we must hold the lock for the >>> VPE. This is now possible since the introduction of the per-VM >>> vmapp_lock, which can be taken before vpe_lock in the locking >>> order. >>> >>> Signed-off-by: Marc Zyngier <maz@kernel.org> >>> --- >>> drivers/irqchip/irq-gic-v3-its.c | 8 ++++++-- >>> 1 file changed, 6 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c >>> index b52d60097cad5..951ec140bcea2 100644 >>> --- a/drivers/irqchip/irq-gic-v3-its.c >>> +++ b/drivers/irqchip/irq-gic-v3-its.c >>> @@ -1810,7 +1810,9 @@ static void its_map_vm(struct its_node *its, struct its_vm *vm) >>> for (i = 0; i < vm->nr_vpes; i++) { >>> struct its_vpe *vpe = vm->vpes[i]; >>> >>> - its_send_vmapp(its, vpe, true); >>> + scoped_guard(raw_spinlock, &vpe->vpe_lock) >>> + its_send_vmapp(its, vpe, true); >>> + >>> its_send_vinvall(its, vpe); >>> } >>> } >>> @@ -1827,8 +1829,10 @@ static void its_unmap_vm(struct its_node *its, struct its_vm *vm) >>> if (!--vm->vlpi_count[its->list_nr]) { >>> int i; >>> >>> - for (i = 0; i < vm->nr_vpes; i++) >>> + for (i = 0; i < vm->nr_vpes; i++) { >>> + guard(raw_spinlock)(&vm->vpes[i]->vpe_lock); >>> its_send_vmapp(its, vm->vpes[i], false); >>> + } >>> } >>> } >>> >> >> Hi Marc, >> >> It looks like there is ABBA deadlock after applying this series: >> >> In its_map_vm: vmapp_lock -> vpe_lock >> In its_vpe_set_affinity: vpe_to_cpuid_lock(vpe_lock) -> its_send_vmovp(vmapp_lock) >> >> Any idea about this? > > Hmmm, well spotted. That's an annoying one. > > Can you give the below hack a go? I've only lightly tested it, as my > D05 box is on its last leg (it is literally falling apart) and I don't > have any other GICv4.x box to test on. > > Thanks, > > M. > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index 951ec140bcea2..b88c6011c8771 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -1328,12 +1328,6 @@ static void its_send_vmovp(struct its_vpe *vpe) > return; > } > > - /* > - * Protect against concurrent updates of the mapping state on > - * individual VMs. > - */ > - guard(raw_spinlock_irqsave)(&vpe->its_vm->vmapp_lock); > - > /* > * Yet another marvel of the architecture. If using the > * its_list "feature", we need to make sure that all ITSs > @@ -3808,7 +3802,7 @@ static int its_vpe_set_affinity(struct irq_data *d, > struct its_vpe *vpe = irq_data_get_irq_chip_data(d); > unsigned int from, cpu = nr_cpu_ids; > struct cpumask *table_mask; > - unsigned long flags; > + unsigned long flags, vmapp_flags; > > /* > * Changing affinity is mega expensive, so let's be as lazy as > @@ -3822,7 +3816,14 @@ static int its_vpe_set_affinity(struct irq_data *d, > * protect us, and that we must ensure nobody samples vpe->col_idx > * during the update, hence the lock below which must also be > * taken on any vLPI handling path that evaluates vpe->col_idx. > + * > + * Finally, we must protect ourselves against concurrent > + * updates of the mapping state on this VM should the ITS list > + * be in use. > */ > + if (its_list_map) > + raw_spin_lock_irqsave(&vpe->its_vm->vmapp_lock, vmapp_flags); > + > from = vpe_to_cpuid_lock(vpe, &flags); > table_mask = gic_data_rdist_cpu(from)->vpe_table_mask; > > @@ -3852,6 +3853,9 @@ static int its_vpe_set_affinity(struct irq_data *d, > irq_data_update_effective_affinity(d, cpumask_of(cpu)); > vpe_to_cpuid_unlock(vpe, flags); > > + if (its_list_map) > + raw_spin_unlock_irqrestore(&vpe->its_vm->vmapp_lock, vmapp_flags); > + > return IRQ_SET_MASK_OK_DONE; > } > Hi Marc， We add above code to do test again. Now it is OK. Bests, Zhou >
On Tue, 23 Jul 2024 02:51:32 +0100, Zhou Wang <wangzhou1@hisilicon.com> wrote: > > On 2024/7/19 19:31, Marc Zyngier wrote: > > On Fri, 19 Jul 2024 10:42:02 +0100, > > Zhou Wang <wangzhou1@hisilicon.com> wrote: > >> > >> On 2024/7/5 17:31, Marc Zyngier wrote: > >>> In order to make sure that vpe->col_idx is correctly sampled > >>> when a VMAPP command is issued, we must hold the lock for the > >>> VPE. This is now possible since the introduction of the per-VM > >>> vmapp_lock, which can be taken before vpe_lock in the locking > >>> order. > >>> > >>> Signed-off-by: Marc Zyngier <maz@kernel.org> > >>> --- > >>> drivers/irqchip/irq-gic-v3-its.c | 8 ++++++-- > >>> 1 file changed, 6 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > >>> index b52d60097cad5..951ec140bcea2 100644 > >>> --- a/drivers/irqchip/irq-gic-v3-its.c > >>> +++ b/drivers/irqchip/irq-gic-v3-its.c > >>> @@ -1810,7 +1810,9 @@ static void its_map_vm(struct its_node *its, struct its_vm *vm) > >>> for (i = 0; i < vm->nr_vpes; i++) { > >>> struct its_vpe *vpe = vm->vpes[i]; > >>> > >>> - its_send_vmapp(its, vpe, true); > >>> + scoped_guard(raw_spinlock, &vpe->vpe_lock) > >>> + its_send_vmapp(its, vpe, true); > >>> + > >>> its_send_vinvall(its, vpe); > >>> } > >>> } > >>> @@ -1827,8 +1829,10 @@ static void its_unmap_vm(struct its_node *its, struct its_vm *vm) > >>> if (!--vm->vlpi_count[its->list_nr]) { > >>> int i; > >>> > >>> - for (i = 0; i < vm->nr_vpes; i++) > >>> + for (i = 0; i < vm->nr_vpes; i++) { > >>> + guard(raw_spinlock)(&vm->vpes[i]->vpe_lock); > >>> its_send_vmapp(its, vm->vpes[i], false); > >>> + } > >>> } > >>> } > >>> > >> > >> Hi Marc, > >> > >> It looks like there is ABBA deadlock after applying this series: > >> > >> In its_map_vm: vmapp_lock -> vpe_lock > >> In its_vpe_set_affinity: vpe_to_cpuid_lock(vpe_lock) -> its_send_vmovp(vmapp_lock) > >> > >> Any idea about this? > > > > Hmmm, well spotted. That's an annoying one. > > > > Can you give the below hack a go? I've only lightly tested it, as my > > D05 box is on its last leg (it is literally falling apart) and I don't > > have any other GICv4.x box to test on. > > > > Thanks, > > > > M. > > > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > > index 951ec140bcea2..b88c6011c8771 100644 > > --- a/drivers/irqchip/irq-gic-v3-its.c > > +++ b/drivers/irqchip/irq-gic-v3-its.c > > @@ -1328,12 +1328,6 @@ static void its_send_vmovp(struct its_vpe *vpe) > > return; > > } > > > > - /* > > - * Protect against concurrent updates of the mapping state on > > - * individual VMs. > > - */ > > - guard(raw_spinlock_irqsave)(&vpe->its_vm->vmapp_lock); > > - > > /* > > * Yet another marvel of the architecture. If using the > > * its_list "feature", we need to make sure that all ITSs > > @@ -3808,7 +3802,7 @@ static int its_vpe_set_affinity(struct irq_data *d, > > struct its_vpe *vpe = irq_data_get_irq_chip_data(d); > > unsigned int from, cpu = nr_cpu_ids; > > struct cpumask *table_mask; > > - unsigned long flags; > > + unsigned long flags, vmapp_flags; > > > > /* > > * Changing affinity is mega expensive, so let's be as lazy as > > @@ -3822,7 +3816,14 @@ static int its_vpe_set_affinity(struct irq_data *d, > > * protect us, and that we must ensure nobody samples vpe->col_idx > > * during the update, hence the lock below which must also be > > * taken on any vLPI handling path that evaluates vpe->col_idx. > > + * > > + * Finally, we must protect ourselves against concurrent > > + * updates of the mapping state on this VM should the ITS list > > + * be in use. > > */ > > + if (its_list_map) > > + raw_spin_lock_irqsave(&vpe->its_vm->vmapp_lock, vmapp_flags); > > + > > from = vpe_to_cpuid_lock(vpe, &flags); > > table_mask = gic_data_rdist_cpu(from)->vpe_table_mask; > > > > @@ -3852,6 +3853,9 @@ static int its_vpe_set_affinity(struct irq_data *d, > > irq_data_update_effective_affinity(d, cpumask_of(cpu)); > > vpe_to_cpuid_unlock(vpe, flags); > > > > + if (its_list_map) > > + raw_spin_unlock_irqrestore(&vpe->its_vm->vmapp_lock, vmapp_flags); > > + > > return IRQ_SET_MASK_OK_DONE; > > } > > > > Hi Marc， > > We add above code to do test again. Now it is OK. Great, thanks for giving it a go. I have just posted an actual patch (with the exact same change) at [1]. It would be good if you could give it a Tested-by: tag. Thanks, M. [1] https://lore.kernel.org/r/20240723175203.3193882-1-maz@kernel.org
On 2024/7/24 1:56, Marc Zyngier wrote: > On Tue, 23 Jul 2024 02:51:32 +0100, > Zhou Wang <wangzhou1@hisilicon.com> wrote: >> >> On 2024/7/19 19:31, Marc Zyngier wrote: >>> On Fri, 19 Jul 2024 10:42:02 +0100, >>> Zhou Wang <wangzhou1@hisilicon.com> wrote: >>>> >>>> On 2024/7/5 17:31, Marc Zyngier wrote: >>>>> In order to make sure that vpe->col_idx is correctly sampled >>>>> when a VMAPP command is issued, we must hold the lock for the >>>>> VPE. This is now possible since the introduction of the per-VM >>>>> vmapp_lock, which can be taken before vpe_lock in the locking >>>>> order. >>>>> >>>>> Signed-off-by: Marc Zyngier <maz@kernel.org> >>>>> --- >>>>> drivers/irqchip/irq-gic-v3-its.c | 8 ++++++-- >>>>> 1 file changed, 6 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c >>>>> index b52d60097cad5..951ec140bcea2 100644 >>>>> --- a/drivers/irqchip/irq-gic-v3-its.c >>>>> +++ b/drivers/irqchip/irq-gic-v3-its.c >>>>> @@ -1810,7 +1810,9 @@ static void its_map_vm(struct its_node *its, struct its_vm *vm) >>>>> for (i = 0; i < vm->nr_vpes; i++) { >>>>> struct its_vpe *vpe = vm->vpes[i]; >>>>> >>>>> - its_send_vmapp(its, vpe, true); >>>>> + scoped_guard(raw_spinlock, &vpe->vpe_lock) >>>>> + its_send_vmapp(its, vpe, true); >>>>> + >>>>> its_send_vinvall(its, vpe); >>>>> } >>>>> } >>>>> @@ -1827,8 +1829,10 @@ static void its_unmap_vm(struct its_node *its, struct its_vm *vm) >>>>> if (!--vm->vlpi_count[its->list_nr]) { >>>>> int i; >>>>> >>>>> - for (i = 0; i < vm->nr_vpes; i++) >>>>> + for (i = 0; i < vm->nr_vpes; i++) { >>>>> + guard(raw_spinlock)(&vm->vpes[i]->vpe_lock); >>>>> its_send_vmapp(its, vm->vpes[i], false); >>>>> + } >>>>> } >>>>> } >>>>> >>>> >>>> Hi Marc, >>>> >>>> It looks like there is ABBA deadlock after applying this series: >>>> >>>> In its_map_vm: vmapp_lock -> vpe_lock >>>> In its_vpe_set_affinity: vpe_to_cpuid_lock(vpe_lock) -> its_send_vmovp(vmapp_lock) >>>> >>>> Any idea about this? >>> >>> Hmmm, well spotted. That's an annoying one. >>> >>> Can you give the below hack a go? I've only lightly tested it, as my >>> D05 box is on its last leg (it is literally falling apart) and I don't >>> have any other GICv4.x box to test on. >>> >>> Thanks, >>> >>> M. >>> >>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c >>> index 951ec140bcea2..b88c6011c8771 100644 >>> --- a/drivers/irqchip/irq-gic-v3-its.c >>> +++ b/drivers/irqchip/irq-gic-v3-its.c >>> @@ -1328,12 +1328,6 @@ static void its_send_vmovp(struct its_vpe *vpe) >>> return; >>> } >>> >>> - /* >>> - * Protect against concurrent updates of the mapping state on >>> - * individual VMs. >>> - */ >>> - guard(raw_spinlock_irqsave)(&vpe->its_vm->vmapp_lock); >>> - >>> /* >>> * Yet another marvel of the architecture. If using the >>> * its_list "feature", we need to make sure that all ITSs >>> @@ -3808,7 +3802,7 @@ static int its_vpe_set_affinity(struct irq_data *d, >>> struct its_vpe *vpe = irq_data_get_irq_chip_data(d); >>> unsigned int from, cpu = nr_cpu_ids; >>> struct cpumask *table_mask; >>> - unsigned long flags; >>> + unsigned long flags, vmapp_flags; >>> >>> /* >>> * Changing affinity is mega expensive, so let's be as lazy as >>> @@ -3822,7 +3816,14 @@ static int its_vpe_set_affinity(struct irq_data *d, >>> * protect us, and that we must ensure nobody samples vpe->col_idx >>> * during the update, hence the lock below which must also be >>> * taken on any vLPI handling path that evaluates vpe->col_idx. >>> + * >>> + * Finally, we must protect ourselves against concurrent >>> + * updates of the mapping state on this VM should the ITS list >>> + * be in use. >>> */ >>> + if (its_list_map) >>> + raw_spin_lock_irqsave(&vpe->its_vm->vmapp_lock, vmapp_flags); >>> + >>> from = vpe_to_cpuid_lock(vpe, &flags); >>> table_mask = gic_data_rdist_cpu(from)->vpe_table_mask; >>> >>> @@ -3852,6 +3853,9 @@ static int its_vpe_set_affinity(struct irq_data *d, >>> irq_data_update_effective_affinity(d, cpumask_of(cpu)); >>> vpe_to_cpuid_unlock(vpe, flags); >>> >>> + if (its_list_map) >>> + raw_spin_unlock_irqrestore(&vpe->its_vm->vmapp_lock, vmapp_flags); >>> + >>> return IRQ_SET_MASK_OK_DONE; >>> } >>> >> >> Hi Marc， >> >> We add above code to do test again. Now it is OK. > > Great, thanks for giving it a go. I have just posted an actual patch > (with the exact same change) at [1]. It would be good if you could > give it a Tested-by: tag. Sure, I will give it a Tested-by. Thanks, Zhou > > Thanks, > > M. > > [1] https://lore.kernel.org/r/20240723175203.3193882-1-maz@kernel.org >
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index b52d60097cad5..951ec140bcea2 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -1810,7 +1810,9 @@ static void its_map_vm(struct its_node *its, struct its_vm *vm) for (i = 0; i < vm->nr_vpes; i++) { struct its_vpe *vpe = vm->vpes[i]; - its_send_vmapp(its, vpe, true); + scoped_guard(raw_spinlock, &vpe->vpe_lock) + its_send_vmapp(its, vpe, true); + its_send_vinvall(its, vpe); } } @@ -1827,8 +1829,10 @@ static void its_unmap_vm(struct its_node *its, struct its_vm *vm) if (!--vm->vlpi_count[its->list_nr]) { int i; - for (i = 0; i < vm->nr_vpes; i++) + for (i = 0; i < vm->nr_vpes; i++) { + guard(raw_spinlock)(&vm->vpes[i]->vpe_lock); its_send_vmapp(its, vm->vpes[i], false); + } } }
In order to make sure that vpe->col_idx is correctly sampled when a VMAPP command is issued, we must hold the lock for the VPE. This is now possible since the introduction of the per-VM vmapp_lock, which can be taken before vpe_lock in the locking order. Signed-off-by: Marc Zyngier <maz@kernel.org> --- drivers/irqchip/irq-gic-v3-its.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)