|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 07/12] x86/IRQ: fix locking around vector management
>>> On 08.05.19 at 15:10, <JBeulich@xxxxxxxx> wrote:
> All of __{assign,bind,clear}_irq_vector() manipulate struct irq_desc
> fields, and hence ought to be called with the descriptor lock held in
> addition to vector_lock. This is currently the case for only
> set_desc_affinity() (in the common case) and destroy_irq(), which also
> clarifies what the nesting behavior between the locks has to be.
> Reflect the new expectation by having these functions all take a
> descriptor as parameter instead of an interrupt number.
>
> Also take care of the two special cases of calls to set_desc_affinity():
> set_ioapic_affinity_irq() and VT-d's dma_msi_set_affinity() get called
> directly as well, and in these cases the descriptor locks hadn't got
> acquired till now. For set_ioapic_affinity_irq() this means acquiring /
> releasing of the IO-APIC lock can be plain spin_{,un}lock() then.
>
> Drop one of the two leading underscores from all three functions at
> the same time.
>
> There's one case left where descriptors get manipulated with just
> vector_lock held: setup_vector_irq() assumes its caller to acquire
> vector_lock, and hence can't itself acquire the descriptor locks (wrong
> lock order). I don't currently see how to address this.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> v2: Also adjust set_ioapic_affinity_irq() and VT-d's
> dma_msi_set_affinity().
I'm sorry, Kevin, I should have Cc-ed you on this one.
Jan
> --- a/xen/arch/x86/io_apic.c
> +++ b/xen/arch/x86/io_apic.c
> @@ -550,14 +550,14 @@ static void clear_IO_APIC (void)
> static void
> set_ioapic_affinity_irq(struct irq_desc *desc, const cpumask_t *mask)
> {
> - unsigned long flags;
> unsigned int dest;
> int pin, irq;
> struct irq_pin_list *entry;
>
> irq = desc->irq;
>
> - spin_lock_irqsave(&ioapic_lock, flags);
> + spin_lock(&ioapic_lock);
> +
> dest = set_desc_affinity(desc, mask);
> if (dest != BAD_APICID) {
> if ( !x2apic_enabled )
> @@ -580,8 +580,8 @@ set_ioapic_affinity_irq(struct irq_desc
> entry = irq_2_pin + entry->next;
> }
> }
> - spin_unlock_irqrestore(&ioapic_lock, flags);
>
> + spin_unlock(&ioapic_lock);
> }
>
> /*
> @@ -674,16 +674,19 @@ void /*__init*/ setup_ioapic_dest(void)
> for (ioapic = 0; ioapic < nr_ioapics; ioapic++) {
> for (pin = 0; pin < nr_ioapic_entries[ioapic]; pin++) {
> struct irq_desc *desc;
> + unsigned long flags;
>
> irq_entry = find_irq_entry(ioapic, pin, mp_INT);
> if (irq_entry == -1)
> continue;
> irq = pin_2_irq(irq_entry, ioapic, pin);
> desc = irq_to_desc(irq);
> +
> + spin_lock_irqsave(&desc->lock, flags);
> BUG_ON(!cpumask_intersects(desc->arch.cpu_mask,
> &cpu_online_map));
> set_ioapic_affinity_irq(desc, desc->arch.cpu_mask);
> + spin_unlock_irqrestore(&desc->lock, flags);
> }
> -
> }
> }
>
> --- a/xen/arch/x86/irq.c
> +++ b/xen/arch/x86/irq.c
> @@ -27,6 +27,7 @@
> #include <public/physdev.h>
>
> static int parse_irq_vector_map_param(const char *s);
> +static void _clear_irq_vector(struct irq_desc *desc);
>
> /* opt_noirqbalance: If true, software IRQ balancing/affinity is disabled.
> */
> bool __read_mostly opt_noirqbalance;
> @@ -120,13 +121,12 @@ static void trace_irq_mask(uint32_t even
> trace_var(event, 1, sizeof(d), &d);
> }
>
> -static int __init __bind_irq_vector(int irq, int vector, const cpumask_t
> *cpu_mask)
> +static int __init _bind_irq_vector(struct irq_desc *desc, int vector,
> + const cpumask_t *cpu_mask)
> {
> cpumask_t online_mask;
> int cpu;
> - struct irq_desc *desc = irq_to_desc(irq);
>
> - BUG_ON((unsigned)irq >= nr_irqs);
> BUG_ON((unsigned)vector >= NR_VECTORS);
>
> cpumask_and(&online_mask, cpu_mask, &cpu_online_map);
> @@ -137,9 +137,9 @@ static int __init __bind_irq_vector(int
> return 0;
> if ( desc->arch.vector != IRQ_VECTOR_UNASSIGNED )
> return -EBUSY;
> - trace_irq_mask(TRC_HW_IRQ_BIND_VECTOR, irq, vector, &online_mask);
> + trace_irq_mask(TRC_HW_IRQ_BIND_VECTOR, desc->irq, vector, &online_mask);
> for_each_cpu(cpu, &online_mask)
> - per_cpu(vector_irq, cpu)[vector] = irq;
> + per_cpu(vector_irq, cpu)[vector] = desc->irq;
> desc->arch.vector = vector;
> cpumask_copy(desc->arch.cpu_mask, &online_mask);
> if ( desc->arch.used_vectors )
> @@ -153,12 +153,18 @@ static int __init __bind_irq_vector(int
>
> int __init bind_irq_vector(int irq, int vector, const cpumask_t *cpu_mask)
> {
> + struct irq_desc *desc = irq_to_desc(irq);
> unsigned long flags;
> int ret;
>
> - spin_lock_irqsave(&vector_lock, flags);
> - ret = __bind_irq_vector(irq, vector, cpu_mask);
> - spin_unlock_irqrestore(&vector_lock, flags);
> + BUG_ON((unsigned)irq >= nr_irqs);
> +
> + spin_lock_irqsave(&desc->lock, flags);
> + spin_lock(&vector_lock);
> + ret = _bind_irq_vector(desc, vector, cpu_mask);
> + spin_unlock(&vector_lock);
> + spin_unlock_irqrestore(&desc->lock, flags);
> +
> return ret;
> }
>
> @@ -243,7 +249,9 @@ void destroy_irq(unsigned int irq)
>
> spin_lock_irqsave(&desc->lock, flags);
> desc->handler = &no_irq_type;
> - clear_irq_vector(irq);
> + spin_lock(&vector_lock);
> + _clear_irq_vector(desc);
> + spin_unlock(&vector_lock);
> desc->arch.used_vectors = NULL;
> spin_unlock_irqrestore(&desc->lock, flags);
>
> @@ -266,11 +274,11 @@ static void release_old_vec(struct irq_d
> }
> }
>
> -static void __clear_irq_vector(int irq)
> +static void _clear_irq_vector(struct irq_desc *desc)
> {
> - int cpu, vector, old_vector;
> + unsigned int cpu;
> + int vector, old_vector, irq = desc->irq;
> cpumask_t tmp_mask;
> - struct irq_desc *desc = irq_to_desc(irq);
>
> BUG_ON(!desc->arch.vector);
>
> @@ -316,11 +324,14 @@ static void __clear_irq_vector(int irq)
>
> void clear_irq_vector(int irq)
> {
> + struct irq_desc *desc = irq_to_desc(irq);
> unsigned long flags;
>
> - spin_lock_irqsave(&vector_lock, flags);
> - __clear_irq_vector(irq);
> - spin_unlock_irqrestore(&vector_lock, flags);
> + spin_lock_irqsave(&desc->lock, flags);
> + spin_lock(&vector_lock);
> + _clear_irq_vector(desc);
> + spin_unlock(&vector_lock);
> + spin_unlock_irqrestore(&desc->lock, flags);
> }
>
> int irq_to_vector(int irq)
> @@ -455,8 +466,7 @@ static vmask_t *irq_get_used_vector_mask
> return ret;
> }
>
> -static int __assign_irq_vector(
> - int irq, struct irq_desc *desc, const cpumask_t *mask)
> +static int _assign_irq_vector(struct irq_desc *desc, const cpumask_t *mask)
> {
> /*
> * NOTE! The local APIC isn't very good at handling
> @@ -470,7 +480,8 @@ static int __assign_irq_vector(
> * 0x80, because int 0x80 is hm, kind of importantish. ;)
> */
> static int current_vector = FIRST_DYNAMIC_VECTOR, current_offset = 0;
> - int cpu, err, old_vector;
> + unsigned int cpu;
> + int err, old_vector, irq = desc->irq;
> vmask_t *irq_used_vectors = NULL;
>
> old_vector = irq_to_vector(irq);
> @@ -583,8 +594,12 @@ int assign_irq_vector(int irq, const cpu
>
> BUG_ON(irq >= nr_irqs || irq <0);
>
> - spin_lock_irqsave(&vector_lock, flags);
> - ret = __assign_irq_vector(irq, desc, mask ?: TARGET_CPUS);
> + spin_lock_irqsave(&desc->lock, flags);
> +
> + spin_lock(&vector_lock);
> + ret = _assign_irq_vector(desc, mask ?: TARGET_CPUS);
> + spin_unlock(&vector_lock);
> +
> if ( !ret )
> {
> ret = desc->arch.vector;
> @@ -593,7 +608,8 @@ int assign_irq_vector(int irq, const cpu
> else
> cpumask_setall(desc->affinity);
> }
> - spin_unlock_irqrestore(&vector_lock, flags);
> +
> + spin_unlock_irqrestore(&desc->lock, flags);
>
> return ret;
> }
> @@ -767,7 +783,6 @@ void irq_complete_move(struct irq_desc *
>
> unsigned int set_desc_affinity(struct irq_desc *desc, const cpumask_t
> *mask)
> {
> - unsigned int irq;
> int ret;
> unsigned long flags;
> cpumask_t dest_mask;
> @@ -775,10 +790,8 @@ unsigned int set_desc_affinity(struct ir
> if (!cpumask_intersects(mask, &cpu_online_map))
> return BAD_APICID;
>
> - irq = desc->irq;
> -
> spin_lock_irqsave(&vector_lock, flags);
> - ret = __assign_irq_vector(irq, desc, mask);
> + ret = _assign_irq_vector(desc, mask);
> spin_unlock_irqrestore(&vector_lock, flags);
>
> if (ret < 0)
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -2134,11 +2134,16 @@ static void adjust_irq_affinity(struct a
> unsigned int node = rhsa ? pxm_to_node(rhsa->proximity_domain)
> : NUMA_NO_NODE;
> const cpumask_t *cpumask = &cpu_online_map;
> + struct irq_desc *desc;
>
> if ( node < MAX_NUMNODES && node_online(node) &&
> cpumask_intersects(&node_to_cpumask(node), cpumask) )
> cpumask = &node_to_cpumask(node);
> - dma_msi_set_affinity(irq_to_desc(drhd->iommu->msi.irq), cpumask);
> +
> + desc = irq_to_desc(drhd->iommu->msi.irq);
> + spin_lock_irq(&desc->lock);
> + dma_msi_set_affinity(desc, cpumask);
> + spin_unlock_irq(&desc->lock);
> }
>
> static int adjust_vtd_irq_affinities(void)
>
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |