Basing the cpu_index on the number of currently allocated vCPUs fails
when vCPUs aren't removed in a LIFO manner. This is especially true
when we are allocating a cpu_index for each guest thread in
linux-user where there is no ordering constraint on their allocation
and de-allocation.
[I've dropped the assert which is there to guard against out-of-order
removal as this should probably be caught higher up the stack. Maybe
we could just ifdef CONFIG_SOFTTMU it?]
Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
Cc: Nikolay Igotti <igo...@gmail.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Igor Mammedov <imamm...@redhat.com>
Cc: Eduardo Habkost <ehabk...@redhat.com>
---
v2
- slightly tweak the index algorithm to preserve cpu_index = 0
---
cpus-common.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/cpus-common.c b/cpus-common.c
index 55d5df89237..70a9d12981a 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -61,13 +61,15 @@ static bool cpu_index_auto_assigned;
static int cpu_get_free_index(void)
{
CPUState *some_cpu;
- int cpu_index = 0;
+ int max_cpu_index = 0;
cpu_index_auto_assigned = true;
CPU_FOREACH(some_cpu) {
- cpu_index++;
+ if (some_cpu->cpu_index >= max_cpu_index) {
+ max_cpu_index = some_cpu->cpu_index + 1;
+ }
}
- return cpu_index;
+ return max_cpu_index;
}
void cpu_list_add(CPUState *cpu)
@@ -90,8 +92,6 @@ void cpu_list_remove(CPUState *cpu)
return;
}
- assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus)));
-
QTAILQ_REMOVE_RCU(&cpus, cpu, node);
cpu->cpu_index = UNASSIGNED_CPU_INDEX;
}
--
2.20.1
