Messages in this thread | | | From | Raghavendra Rao Ananta <> | Date | Mon, 18 Sep 2023 09:58:31 -0700 | Subject | Re: [PATCH v5 02/12] KVM: arm64: PMU: Set the default PMU for the guest on vCPU reset |
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On Mon, Sep 18, 2023 at 9:47 AM Oliver Upton <oliver.upton@linux.dev> wrote: > > On Mon, Sep 18, 2023 at 09:41:02AM -0700, Raghavendra Rao Ananta wrote: > > On Fri, Sep 15, 2023 at 12:33 PM Oliver Upton <oliver.upton@linux.dev> wrote: > > [...] > > > > This would eliminate the possibility of returning ENODEV to userspace > > > where we shouldn't. > > > > > I understand that we'll be breaking the API contract and userspace may > > have to adapt to this change, but is it not acceptable to document and > > return ENODEV, since ENODEV may offer more clarity to userspace as to > > why the ioctl failed? In general, do we never extend the APIs? > > Yes, we extend the existing interfaces all the time, but we almost > always require user opt in for user-visible changes in behavior. Look at > the way arm64_check_features() is handled -- we hide the 'detailed' > error and return EINVAL due to UAPI. > Got it. Let's return EINVAL then. Thanks!
- Raghavendra > -- > Thanks, > Oliver
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