From: Zhenyu Ye <yezhenyu2@huawei.com>
To: Paolo Bonzini <pbonzini@redhat.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 16:21:40 +0800 [thread overview]
Message-ID: <18baa777-7f28-8f57-e815-11175bf4c59a@huawei.com> (raw)
In-Reply-To: <cffcf9e1-6675-6815-ccfc-f48497ade818@redhat.com>
On 2020/7/31 14:44, Paolo Bonzini wrote:
> 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.
>
I will try to do this. :)
Zhenyu
prev parent reply other threads:[~2020-07-31 8:21 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
2020-07-31 8:21 ` Zhenyu Ye [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=18baa777-7f28-8f57-e815-11175bf4c59a@huawei.com \
--to=yezhenyu2@huawei.com \
--cc=gleb@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=pbonzini@redhat.com \
--cc=xiexiangyou@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).