From: Paolo Bonzini <pbonzini@redhat.com>
To: Zhenyu Ye <yezhenyu2@huawei.com>
Cc: "S. Tsirkin, Michael" <mst@redhat.com>,
gleb@redhat.com, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
kvmarm@lists.cs.columbia.edu,
Xiexiangyou <xiexiangyou@huawei.com>
Subject: Re: [Question] the check of ioeventfd collision in kvm_*assign_ioeventfd_idx
Date: Fri, 31 Jul 2020 08:44:56 +0200 [thread overview]
Message-ID: <cffcf9e1-6675-6815-ccfc-f48497ade818@redhat.com> (raw)
In-Reply-To: <4aa75d90-f2d2-888c-8970-02a41f3733e4@huawei.com>
On 31/07/20 08:39, Zhenyu Ye wrote:
> On 2020/7/31 2:03, Paolo Bonzini wrote:
>> Yes, I think it's not needed. Probably the deassign check can be turned into an assertion?
>>
>> Paolo
>>
>
> I think we can do this in the same function, and turnt he check of
> p->eventfd into assertion in kvm_deassign_ioeventfd_idx(). Just like:
>
> ---8<---
> static inline struct _ioeventfd *
> get_ioeventfd(struct kvm *kvm, enum kvm_bus bus_idx,
> struct kvm_ioeventfd *args)
> {
> static struct _ioeventfd *_p;
> bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
>
> list_for_each_entry(_p, &kvm->ioeventfds, list)
> if (_p->bus_idx == bus_idx &&
> _p->addr == args->addr &&
> (!_p->length || !args->len ||
> (_p->length == args->len &&
> (_p->wildcard || wildcard ||
> _p->datamatch == args->datamatch))))
> return _p;
>
> return NULL;
> }
>
> kvm_deassign_ioeventfd_idx() {
> ...
> p = get_ioeventfd(kvm, bus_idx, args);
> if (p) {
> assert(p->eventfd == eventfd);
> ...
> }
>
> ---8<----
>
> This may be easier to understand (keep the same logic in assign/deassign).
I think you should also warn if:
1) p->length != args->len
2) p->wildcard != args->wildcard if p->length
3) p->datamatch != args->datamatch if p->length && !p->wildcard
but yeah it sounds like a plan.
Paolo
next prev parent reply other threads:[~2020-07-31 6:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 14:19 [Question] the check of ioeventfd collision in kvm_*assign_ioeventfd_idx Zhenyu Ye
[not found] ` <CABgObfbFXYodCeGWSnKw0j_n2-QLxpnD_Uyc5r-_ApXv=x+qmw@mail.gmail.com>
2020-07-31 6:39 ` Zhenyu Ye
2020-07-31 6:44 ` Paolo Bonzini [this message]
2020-07-31 8:21 ` Zhenyu Ye
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