From: Paolo Bonzini <pbonzini@redhat.com>
To: "Roman Kagan" <rkagan@virtuozzo.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
"Haiyang Zhang" <haiyangz@microsoft.com>,
"Stephen Hemminger" <sthemmin@microsoft.com>,
"Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h
Date: Wed, 28 Nov 2018 09:40:01 +0100 [thread overview]
Message-ID: <0b29458b-a605-8f87-bbaa-62a90cba5e2b@redhat.com> (raw)
In-Reply-To: <20181127184835.GA5147@rkaganip.lan>
On 27/11/18 19:48, Roman Kagan wrote:
> On Tue, Nov 27, 2018 at 02:10:49PM +0100, Vitaly Kuznetsov wrote:
>> Roman Kagan <rkagan@virtuozzo.com> writes:
>>> On Mon, Nov 26, 2018 at 04:47:29PM +0100, Vitaly Kuznetsov wrote:
>>> I personally tend to prefer masks over bitfields, so I'd rather do the
>>> consolidation in the opposite direction: use the definitions in
>>> hyperv-tlfs.h and replace those unions/bitfields elsewhere. (I vaguely
>>> remember posting such a patchset a couple of years ago but I lacked the
>>> motivation to complete it).
>>
>> Are there any known advantages of using masks over bitfields or the
>> resulting binary code is the same?
>
> Strictly speaking bitwise ops are portable while bitfields are not, but
> I guess this is not much of an issue with gcc which is dependable to
> produce the right thing.
>
> I came to dislike the bitfields for the false feeling of atomicity of
> assignment while most of the time they are read-modify-write operations.
>
> And no, I don't feel strong about it, so if nobody backs me on this I
> give up :)
I agree, but I am deferring to the Hyper-V maintainers. KVM is mostly
reading these structs.
Paolo
next prev parent reply other threads:[~2018-11-28 8:40 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 15:47 [PATCH v2 0/4] x86/kvm/hyper-v: Implement Direct Mode for synthetic timers Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h Vitaly Kuznetsov
2018-11-26 17:00 ` Michael Kelley
2018-11-26 20:04 ` Roman Kagan
2018-11-27 13:10 ` Vitaly Kuznetsov
2018-11-27 15:52 ` Michael Kelley
2018-11-27 16:32 ` Vitaly Kuznetsov
2018-11-27 18:48 ` Roman Kagan
2018-11-28 1:49 ` Nadav Amit
2018-11-28 10:37 ` Vitaly Kuznetsov
2018-11-28 13:07 ` Thomas Gleixner
2018-11-28 17:55 ` Nadav Amit
2018-11-29 11:36 ` Vitaly Kuznetsov
2018-11-29 19:22 ` Thomas Gleixner
2018-11-29 7:52 ` Roman Kagan
2018-11-28 8:40 ` Paolo Bonzini [this message]
2018-11-26 15:47 ` [PATCH v2 2/4] x86/kvm/hyper-v: use stimer config definition from hyperv-tlfs.h Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 3/4] x86/kvm/hyper-v: direct mode for synthetic timers Vitaly Kuznetsov
2018-11-26 16:44 ` Paolo Bonzini
2018-11-26 17:14 ` Vitaly Kuznetsov
2018-11-27 8:37 ` Roman Kagan
2018-11-27 13:54 ` Paolo Bonzini
2018-11-27 19:05 ` Roman Kagan
2018-11-28 8:43 ` Paolo Bonzini
2018-11-27 8:21 ` Roman Kagan
2018-12-03 17:12 ` Roman Kagan
2018-12-04 12:36 ` Vitaly Kuznetsov
2018-12-10 12:06 ` Roman Kagan
2018-12-10 12:54 ` Vitaly Kuznetsov
2018-12-10 13:21 ` Roman Kagan
2018-12-10 14:53 ` Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 4/4] x86/kvm/hyper-v: avoid open-coding stimer_mark_pending() in kvm_hv_notify_acked_sint() Vitaly Kuznetsov
2018-11-26 16:45 ` Paolo Bonzini
2018-11-27 8:49 ` Roman Kagan
2018-11-26 16:45 ` [PATCH v2 0/4] x86/kvm/hyper-v: Implement Direct Mode for synthetic timers Paolo Bonzini
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=0b29458b-a605-8f87-bbaa-62a90cba5e2b@redhat.com \
--to=pbonzini@redhat.com \
--cc=Michael.H.Kelley@microsoft.com \
--cc=haiyangz@microsoft.com \
--cc=kvm@vger.kernel.org \
--cc=kys@microsoft.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rkagan@virtuozzo.com \
--cc=rkrcmar@redhat.com \
--cc=sthemmin@microsoft.com \
--cc=vkuznets@redhat.com \
--cc=x86@kernel.org \
/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).