Improve the handling of cpuset with interrupts.

- For x86, change the interrupt source method to assign an interrupt source
  to a specific CPU to return an error value instead of void, thus allowing
  it to fail.
- If moving an interrupt to a CPU fails due to a lack of IDT vectors in the
  destination CPU, fail the request with ENOSPC rather than panicing.
- For MSI interrupts on x86 (but not MSI-X), only allow cpuset to be used
  on the first interrupt in a group.  Moving the first interrupt in a group
  moves the entire group.
- Use the icu_lock to protect intr_next_cpu() on x86 instead of the
  intr_table_lock to fix a LOR introduced in the last set of MSI changes.
- Add a new privilege PRIV_SCHED_CPUSET_INTR for using cpuset with
  interrupts.  Previously, binding an interrupt to a CPU only performed a
  privilege check if the interrupt had an interrupt thread.  Interrupts
  without a thread could be bound by non-root users as a result.
- If an interrupt event's assign_cpu method fails, then restore the original
  cpuset mask for the associated interrupt thread.

Approved by:	re (kib)

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/i386/isa/atpic.c b/sys/i386/isa/atpic.c
index dfeeb21..37a1285 100644
--- a/sys/i386/isa/atpic.c
+++ b/sys/i386/isa/atpic.c
@@ -161,7 +161,7 @@ static void atpic_resume(struct pic *pic);
 static int atpic_source_pending(struct intsrc *isrc);
 static int atpic_config_intr(struct intsrc *isrc, enum intr_trigger trig,
     enum intr_polarity pol);
-static void atpic_assign_cpu(struct intsrc *isrc, u_int apic_id);
+static int atpic_assign_cpu(struct intsrc *isrc, u_int apic_id);
 static void i8259_init(struct atpic *pic, int slave);
 
 static struct atpic atpics[] = {
@@ -389,7 +389,7 @@ atpic_config_intr(struct intsrc *isrc, enum intr_trigger trig,
 #endif /* PC98 */
 }
 
-static void
+static int
 atpic_assign_cpu(struct intsrc *isrc, u_int apic_id)
 {