Messages in this thread | | | Date | Mon, 25 Jul 2022 17:39:11 +0800 | Subject | Re: [PATCH 1/1] iommu/vt-d: Fix possible recursive locking in intel_iommu_init() | From | Baolu Lu <> |
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On 2022/7/25 15:40, Tian, Kevin wrote: >> From: Baolu Lu <baolu.lu@linux.intel.com> >> Sent: Sunday, July 24, 2022 11:00 AM >> >> Hi Kevin, >> >> On 2022/7/21 15:39, Tian, Kevin wrote: >>>> From: Lu Baolu <baolu.lu@linux.intel.com> >>>> Sent: Tuesday, July 19, 2022 7:53 AM >>>> >>>> @@ -88,7 +89,8 @@ extern struct list_head dmar_drhd_units; >>>> static inline bool dmar_rcu_check(void) >>>> { >>>> return rwsem_is_locked(&dmar_global_lock) || >>>> - system_state == SYSTEM_BOOTING; >>>> + system_state == SYSTEM_BOOTING || >>>> + (IS_ENABLED(CONFIG_INTEL_IOMMU) >>>> && !intel_iommu_enabled); >>>> } >>> >>> intel_iommu_enabled is 0 if CONFIG_INTEL_IOMMU is not set. >>> >>> same for other similar checks. >> >> Sorry that I didn't get your point. If CONFIG_INTEL_IOMMU is not set, >> IS_ENABLED(CONFIG_INTEL_IOMMU) is 0. The adding check has no effect. >> Did >> I miss anything? >> > > My point was that the check on CONFIG_INTEL_IOMMU is unnecessary.
Oh, if INTEL_IOMMU is not configured, the interrupt remapping could also be supported, so we still need the rcu protection. We only relax the rcu check when INTEL_IOMMU is configured, but not enabled yet.
Best regards, baolu
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