Messages in this thread | | | Date | Tue, 30 May 2023 16:51:25 -0700 | Subject | Re: [PATCH v2 1/6] KVM: x86/mmu: add a new mmu zap helper to indicate memtype changes | From | Sean Christopherson <> |
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On Tue, May 30, 2023, Yan Zhao wrote: > On Thu, May 25, 2023 at 08:54:15AM -0700, Sean Christopherson wrote: > And I combined the __kvm_mmu_honors_guest_mtrrs() into > kvm_mmu_honors_guest_mtrrs(). Not sure if you like it :)
I would prefer to provide a separater inner helper, mainly so that the common case callers don't need to pass %false. I don't love passing bools, but it's tolerable for a one-off use of an inner helper.
> +/* > + * Returns if KVM honors guest MTRRs > + * @override_vm_has_noncoherent_dma: Allow caller to override non-coherent DMA > + * status returned from > + * kvm_arch_has_noncoherent_dma() > + */ > +bool kvm_mmu_honors_guest_mtrrs(struct kvm *kvm, > + bool override_vm_has_noncoherent_dma) > +{ > + bool noncoherent_dma = override_vm_has_noncoherent_dma ? true : > + kvm_arch_has_noncoherent_dma(kvm);
The "override" name is confusing, e.g. it won't be clear when it's safe/correct for a new caller to override kvm_arch_has_noncoherent_dma(). If we go with a single helper, I could live with:
bool kvm_mmu_honors_guest_mtrrs(struct kvm *kvm, bool stopping_noncoherent_dma) { bool noncoherent_dma = stopping_noncoherent_dma || kvm_arch_has_noncoherent_dma(kvm);
... }
but that makes it awkward to use common code for start+stop assignment, and as above there are three "normal" callers that would have to pass magic %false values regardless of the name.
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