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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen staging] x86/IRQ: fix locking around vector management
commit 650c31d3af8a6a4a7174633f93ed9405e9c8d279
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Jul 22 11:44:02 2019 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jul 22 11:44:02 2019 +0200
x86/IRQ: fix locking around vector management
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>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> [VT-d]
Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/io_apic.c | 11 +++---
xen/arch/x86/irq.c | 68 ++++++++++++++++++++++---------------
xen/drivers/passthrough/vtd/iommu.c | 7 +++-
3 files changed, 54 insertions(+), 32 deletions(-)
diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c
index 92fed9d2bc..f93f711051 100644
--- 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 *desc, const
cpumask_t *mask)
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);
}
-
}
}
diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 0462e28d46..10a83efc8e 100644
--- 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;
@@ -143,13 +144,12 @@ static void trace_irq_mask(uint32_t event, int irq, int
vector,
_trace_irq_mask(event, irq, vector, mask);
}
-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);
@@ -160,9 +160,9 @@ static int __init __bind_irq_vector(int irq, int vector,
const cpumask_t *cpu_ma
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 )
@@ -176,12 +176,18 @@ static int __init __bind_irq_vector(int irq, int vector,
const cpumask_t *cpu_ma
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;
}
@@ -266,18 +272,20 @@ 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);
xfree(action);
}
-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);
@@ -323,11 +331,14 @@ 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)
@@ -462,8 +473,7 @@ static vmask_t *irq_get_used_vector_mask(int irq)
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
@@ -477,7 +487,8 @@ 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);
@@ -590,8 +601,12 @@ int assign_irq_vector(int irq, const cpumask_t *mask)
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;
@@ -600,14 +615,16 @@ int assign_irq_vector(int irq, const cpumask_t *mask)
else
cpumask_setall(desc->affinity);
}
- spin_unlock_irqrestore(&vector_lock, flags);
+
+ spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
/*
* Initialize vector_irq on a new cpu. This function must be called
- * with vector_lock held.
+ * with vector_lock held. For this reason it may not itself acquire
+ * the IRQ descriptor locks, as lock nesting is the other way around.
*/
void setup_vector_irq(unsigned int cpu)
{
@@ -775,7 +792,6 @@ void irq_complete_move(struct irq_desc *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;
@@ -783,10 +799,8 @@ unsigned int set_desc_affinity(struct irq_desc *desc,
const cpumask_t *mask)
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)
@@ -2453,7 +2467,7 @@ void fixup_irqs(const cpumask_t *mask, bool verbose)
/*
* In order for the affinity adjustment below to be successful, we
- * need __assign_irq_vector() to succeed. This in particular means
+ * need _assign_irq_vector() to succeed. This in particular means
* clearing desc->arch.move_in_progress if this would otherwise
* prevent the function from succeeding. Since there's no way for the
* flag to get cleared anymore when there's no possible destination
diff --git a/xen/drivers/passthrough/vtd/iommu.c
b/xen/drivers/passthrough/vtd/iommu.c
index 8b27d7e775..f0e8a419b3 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -2134,11 +2134,16 @@ static void adjust_irq_affinity(struct acpi_drhd_unit
*drhd)
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)
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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