mirror of
https://github.com/projectacrn/acrn-hypervisor.git
synced 2025-05-03 14:06:54 +00:00
a06f2d68dc
Current code is missing to handle the following race condition:
Before:
sti
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V
handle softirq with
a while loop
| <----- if a new softirq generated at this point,
V it will be missed to be handled.
cli
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V
return with unclear softirq bitmap
After:
again:
sti
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V
handle softirq with
a while loop
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V
cli
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V
check if a new softirq generated, if yes,
jump back to above again lable point,
and do a while loop again.
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V
return with clear softirq bitmap
Signed-off-by: Zheng, Gen <gen.zheng@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
90 lines
1.5 KiB
C
90 lines
1.5 KiB
C
/*
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* Copyright (C) 2018 Intel Corporation. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <hypervisor.h>
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void disable_softirq(int cpu_id)
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{
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bitmap_clear(SOFTIRQ_ATOMIC, &per_cpu(softirq_pending, cpu_id));
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}
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void enable_softirq(int cpu_id)
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{
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bitmap_set(SOFTIRQ_ATOMIC, &per_cpu(softirq_pending, cpu_id));
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}
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void init_softirq(void)
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{
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int cpu_id;
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for (cpu_id = 0; cpu_id < phy_cpu_num; cpu_id++) {
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per_cpu(softirq_pending, cpu_id) = 0;
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bitmap_set(SOFTIRQ_ATOMIC, &per_cpu(softirq_pending, cpu_id));
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}
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}
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void raise_softirq(int softirq_id)
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{
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int cpu_id = get_cpu_id();
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uint64_t *bitmap = &per_cpu(softirq_pending, cpu_id);
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if (cpu_id >= phy_cpu_num)
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return;
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bitmap_set(softirq_id, bitmap);
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}
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void exec_softirq(void)
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{
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int cpu_id = get_cpu_id();
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volatile uint64_t *bitmap = &per_cpu(softirq_pending, cpu_id);
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int softirq_id;
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if (cpu_id >= phy_cpu_num)
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return;
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if (((*bitmap) & SOFTIRQ_MASK) == 0UL)
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return;
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/* Disable softirq
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* SOFTIRQ_ATOMIC bit = 0 means softirq already in execution
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*/
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if (!bitmap_test_and_clear(SOFTIRQ_ATOMIC, bitmap))
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return;
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again:
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CPU_IRQ_ENABLE();
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while (1) {
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softirq_id = ffs64(*bitmap);
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if ((softirq_id < 0) || (softirq_id >= SOFTIRQ_MAX))
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break;
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bitmap_clear(softirq_id, bitmap);
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switch (softirq_id) {
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case SOFTIRQ_TIMER:
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timer_softirq(cpu_id);
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break;
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case SOFTIRQ_DEV_ASSIGN:
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ptdev_softirq(cpu_id);
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break;
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default:
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break;
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}
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}
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CPU_IRQ_DISABLE();
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if (((*bitmap) & SOFTIRQ_MASK))
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goto again;
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enable_softirq(cpu_id);
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}
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