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[PATCH v1 5/8] cpus-common: ensure auto-assigned cpu_indexes don't clash
From: |
Alex Bennée |
Subject: |
[PATCH v1 5/8] cpus-common: ensure auto-assigned cpu_indexes don't clash |
Date: |
Wed, 13 May 2020 18:31:57 +0100 |
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 <address@hidden>
Cc: Nikolay Igotti <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: Igor Mammedov <address@hidden>
Cc: Eduardo Habkost <address@hidden>
---
cpus-common.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/cpus-common.c b/cpus-common.c
index 55d5df89237..5a7d2f6132b 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -61,13 +61,14 @@ 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++;
+ max_cpu_index = MAX(some_cpu->cpu_index, max_cpu_index);
}
- return cpu_index;
+ max_cpu_index++;
+ return max_cpu_index;
}
void cpu_list_add(CPUState *cpu)
@@ -90,8 +91,6 @@ 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
[PATCH v1 7/8] tests/tcg: add new threadcount test, Alex Bennée, 2020/05/13
[PATCH v1 6/8] linux-user: properly "unrealize" vCPU object, Alex Bennée, 2020/05/13
[PATCH v1 4/8] MAINTAINERS: update the orphaned cpus-common.c file, Alex Bennée, 2020/05/13