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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen staging] x86/IRQ: consolidate use of ->arch.cpu_mask
commit 481a478b3af4b1b33f9a121192a743f17a901457
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Jul 22 11:43:16 2019 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jul 22 11:43:16 2019 +0200
x86/IRQ: consolidate use of ->arch.cpu_mask
Mixed meaning was implied so far by different pieces of code -
disagreement was in particular about whether to expect offline CPUs'
bits to possibly be set. Switch to a mostly consistent meaning
(exception being high priority interrupts, which would perhaps better
be switched to the same model as well in due course). Use the field to
record the vector allocation mask, i.e. potentially including bits of
offline (parked) CPUs. This implies that before passing the mask to
certain functions (most notably cpu_mask_to_apicid()) it needs to be
further reduced to the online subset.
The exception of high priority interrupts is also why for the moment
_bind_irq_vector() is left as is, despite looking wrong: It's used
exclusively for IRQ0, which isn't supposed to move off CPU0 at any time.
The prior lack of restricting to online CPUs in set_desc_affinity()
before calling cpu_mask_to_apicid() in particular allowed (in x2APIC
clustered mode) offlined CPUs to end up enabled in an IRQ's destination
field. (I wonder whether vector_allocation_cpumask_flat() shouldn't
follow a similar model, using cpu_present_map in favor of
cpu_online_map.)
For IO-APIC code it was definitely wrong to potentially store, as a
fallback, TARGET_CPUS (i.e. all online ones) into the field, as that
would have caused problems when determining on which CPUs to release
vectors when they've gone out of use. Disable interrupts instead when
no valid target CPU can be established (which code elsewhere should
guarantee to never happen), and log a message in such an unlikely event.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/io_apic.c | 35 +++++++++++++++++++++++++++--------
xen/arch/x86/irq.c | 22 +++++++++++++---------
xen/include/asm-x86/irq.h | 6 ++++++
3 files changed, 46 insertions(+), 17 deletions(-)
diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c
index 02e3a263a6..92fed9d2bc 100644
--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -680,7 +680,7 @@ void /*__init*/ setup_ioapic_dest(void)
continue;
irq = pin_2_irq(irq_entry, ioapic, pin);
desc = irq_to_desc(irq);
- BUG_ON(cpumask_empty(desc->arch.cpu_mask));
+ BUG_ON(!cpumask_intersects(desc->arch.cpu_mask, &cpu_online_map));
set_ioapic_affinity_irq(desc, desc->arch.cpu_mask);
}
@@ -2194,7 +2194,6 @@ int io_apic_set_pci_routing (int ioapic, int pin, int
irq, int edge_level, int a
{
struct irq_desc *desc = irq_to_desc(irq);
struct IO_APIC_route_entry entry;
- cpumask_t mask;
unsigned long flags;
int vector;
@@ -2229,11 +2228,17 @@ int io_apic_set_pci_routing (int ioapic, int pin, int
irq, int edge_level, int a
return vector;
entry.vector = vector;
- cpumask_copy(&mask, TARGET_CPUS);
- /* Don't chance ending up with an empty mask. */
- if (cpumask_intersects(&mask, desc->arch.cpu_mask))
- cpumask_and(&mask, &mask, desc->arch.cpu_mask);
- SET_DEST(entry, logical, cpu_mask_to_apicid(&mask));
+ if (cpumask_intersects(desc->arch.cpu_mask, TARGET_CPUS)) {
+ cpumask_t *mask = this_cpu(scratch_cpumask);
+
+ cpumask_and(mask, desc->arch.cpu_mask, TARGET_CPUS);
+ SET_DEST(entry, logical, cpu_mask_to_apicid(mask));
+ } else {
+ printk(XENLOG_ERR "IRQ%d: no target CPU (%*pb vs %*pb)\n",
+ irq, nr_cpu_ids, cpumask_bits(desc->arch.cpu_mask),
+ nr_cpu_ids, cpumask_bits(TARGET_CPUS));
+ desc->status |= IRQ_DISABLED;
+ }
apic_printk(APIC_DEBUG, KERN_DEBUG "IOAPIC[%d]: Set PCI routing entry "
"(%d-%d -> %#x -> IRQ %d Mode:%i Active:%i)\n", ioapic,
@@ -2419,7 +2424,21 @@ int ioapic_guest_write(unsigned long physbase, unsigned
int reg, u32 val)
/* Set the vector field to the real vector! */
rte.vector = desc->arch.vector;
- SET_DEST(rte, logical, cpu_mask_to_apicid(desc->arch.cpu_mask));
+ if ( cpumask_intersects(desc->arch.cpu_mask, TARGET_CPUS) )
+ {
+ cpumask_t *mask = this_cpu(scratch_cpumask);
+
+ cpumask_and(mask, desc->arch.cpu_mask, TARGET_CPUS);
+ SET_DEST(rte, logical, cpu_mask_to_apicid(mask));
+ }
+ else
+ {
+ gprintk(XENLOG_ERR, "IRQ%d: no target CPU (%*pb vs %*pb)\n",
+ irq, nr_cpu_ids, cpumask_bits(desc->arch.cpu_mask),
+ nr_cpu_ids, cpumask_bits(TARGET_CPUS));
+ desc->status |= IRQ_DISABLED;
+ rte.mask = 1;
+ }
__ioapic_write_entry(apic, pin, 0, rte);
diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 1acc351c67..0462e28d46 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -478,11 +478,13 @@ static int __assign_irq_vector(
*/
static int current_vector = FIRST_DYNAMIC_VECTOR, current_offset = 0;
int cpu, err, old_vector;
- cpumask_t tmp_mask;
vmask_t *irq_used_vectors = NULL;
old_vector = irq_to_vector(irq);
- if (old_vector > 0) {
+ if ( old_vector > 0 )
+ {
+ cpumask_t tmp_mask;
+
cpumask_and(&tmp_mask, mask, &cpu_online_map);
if (cpumask_intersects(&tmp_mask, desc->arch.cpu_mask)) {
desc->arch.vector = old_vector;
@@ -505,7 +507,9 @@ static int __assign_irq_vector(
else
irq_used_vectors = irq_get_used_vector_mask(irq);
- for_each_cpu(cpu, mask) {
+ for_each_cpu(cpu, mask)
+ {
+ const cpumask_t *vec_mask;
int new_cpu;
int vector, offset;
@@ -513,8 +517,7 @@ static int __assign_irq_vector(
if (!cpu_online(cpu))
continue;
- cpumask_and(&tmp_mask, vector_allocation_cpumask(cpu),
- &cpu_online_map);
+ vec_mask = vector_allocation_cpumask(cpu);
vector = current_vector;
offset = current_offset;
@@ -535,7 +538,7 @@ next:
&& test_bit(vector, irq_used_vectors) )
goto next;
- for_each_cpu(new_cpu, &tmp_mask)
+ for_each_cpu(new_cpu, vec_mask)
if (per_cpu(vector_irq, new_cpu)[vector] >= 0)
goto next;
/* Found one! */
@@ -554,12 +557,12 @@ next:
release_old_vec(desc);
}
- trace_irq_mask(TRC_HW_IRQ_ASSIGN_VECTOR, irq, vector, &tmp_mask);
+ trace_irq_mask(TRC_HW_IRQ_ASSIGN_VECTOR, irq, vector, vec_mask);
- for_each_cpu(new_cpu, &tmp_mask)
+ for_each_cpu(new_cpu, vec_mask)
per_cpu(vector_irq, new_cpu)[vector] = irq;
desc->arch.vector = vector;
- cpumask_copy(desc->arch.cpu_mask, &tmp_mask);
+ cpumask_copy(desc->arch.cpu_mask, vec_mask);
desc->arch.used = IRQ_USED;
ASSERT((desc->arch.used_vectors == NULL)
@@ -791,6 +794,7 @@ unsigned int set_desc_affinity(struct irq_desc *desc, const
cpumask_t *mask)
cpumask_copy(desc->affinity, mask);
cpumask_and(&dest_mask, mask, desc->arch.cpu_mask);
+ cpumask_and(&dest_mask, &dest_mask, &cpu_online_map);
return cpu_mask_to_apicid(&dest_mask);
}
diff --git a/xen/include/asm-x86/irq.h b/xen/include/asm-x86/irq.h
index c0c6e7c799..bc0c0c15d2 100644
--- a/xen/include/asm-x86/irq.h
+++ b/xen/include/asm-x86/irq.h
@@ -32,6 +32,12 @@ struct irq_desc;
struct arch_irq_desc {
s16 vector; /* vector itself is only 8 bits, */
s16 old_vector; /* but we use -1 for unassigned */
+ /*
+ * Except for high priority interrupts @cpu_mask may have bits set for
+ * offline CPUs. Consumers need to be careful to mask this down to
+ * online ones as necessary. There is supposed to always be a non-
+ * empty intersection with cpu_online_map.
+ */
cpumask_var_t cpu_mask;
cpumask_var_t old_cpu_mask;
cpumask_var_t pending_mask;
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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