| Subject | Re: [PATCH 19/24] kvm: x86/mmu: Protect tdp_mmu_pages with a lock | From | Paolo Bonzini <> | Date | Tue, 26 Jan 2021 14:37:32 +0100 |
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On 12/01/21 19:10, Ben Gardon wrote: > + * May be acquired under the MMU lock in read mode or non-overlapping > + * with the MMU lock. > + */ > + spinlock_t tdp_mmu_pages_lock;
Is this correct? My understanding is that:
- you can take tdp_mmu_pages_lock from a shared MMU lock critical section
- you don't need to take tdp_mmu_pages_lock from an exclusive MMU lock critical section, because you can't be concurrent with a shared critical section
- but then, you can't take tdp_mmu_pages_lock outside the MMU lock, because you could have
write_lock(mmu_lock) spin_lock(tdp_mmu_pages_lock) do tdp_mmu_pages_lock stuff !!! do tdp_mmu_pages_lock stuff write_unlock(mmu_lock) spin_unlock(tdp_mmu_pages_lock)
Paolo
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