From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: "Jiahuan Zhang" <jiahuanzhang90@gmail.com>,
"QEMU Developers" <qemu-devel@nongnu.org>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>
Subject: Re: [Qemu-devel] Guest application reading from pl011 without device driver
Date: Wed, 22 Mar 2017 04:40:25 -0400 (EDT) [thread overview]
Message-ID: <1322109813.6444955.1490172025040.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <CAFEAcA_t9iLude4Vu3Zc=_wcXMTtFb4Q4oJ8O+zLAJ9isAPqHQ@mail.gmail.com>
> > I am using a windows named pipe to get the data from a window
> > host program, which uses ReadFile () in char_win.c
>
> OK, bugs in the windows-specific char backend would be
> unsurprising.
>
> I'm not entirely sure how the chardev layer works, but
> at the pl011 end if we return 0 from our can_receive
> function then the chardev layer should decide it has
> nothing to do until the pl011 later calls
> qemu_chr_fe_accept_input(), I think.
>
> I've cc'd Paolo and Marc-André Lureau as the chardev
> maintainers.
Windows named pipes do not support the equivalent of "select",
so it's possible that they cause a busy wait. Try using a
TCP socket instead and see if the bug goes away.
Paolo
next prev parent reply other threads:[~2017-03-22 8:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 16:32 [Qemu-devel] Guest application reading from pl011 without device driver Jiahuan Zhang
2017-03-21 16:39 ` Peter Maydell
2017-03-21 16:47 ` Jiahuan Zhang
2017-03-21 16:50 ` Peter Maydell
2017-03-21 16:59 ` Jiahuan Zhang
2017-03-21 17:10 ` Jiahuan Zhang
2017-03-21 17:16 ` Peter Maydell
2017-03-21 17:48 ` Jiahuan Zhang
2017-03-21 17:55 ` Peter Maydell
[not found] ` <CAJy91CZ4Ed-HGHLkzEc1dqQbo32d-eTE1S1ovO_ZwkDdTpkQXQ@mail.gmail.com>
[not found] ` <CAJy91CaCV40FgSP55qWZeZgkQ=2+E8Cr7xdbu9pn5HLEo+6JJQ@mail.gmail.com>
2017-03-21 18:11 ` Jiahuan Zhang
2017-03-21 18:28 ` Peter Maydell
2017-03-21 18:33 ` Jiahuan Zhang
2017-03-22 8:40 ` Paolo Bonzini [this message]
2017-03-22 8:48 ` Jiahuan Zhang
2017-03-22 9:37 ` Paolo Bonzini
2017-03-22 10:28 ` Jiahuan Zhang
2017-03-22 11:27 ` Paolo Bonzini
2017-03-23 10:12 ` Jiahuan Zhang
2017-03-23 10:35 ` Paolo Bonzini
2017-03-23 17:28 ` Jiahuan Zhang
2017-03-23 17:31 ` Paolo Bonzini
2017-03-24 7:24 ` Jiahuan Zhang
2017-03-24 10:00 ` Jiahuan Zhang
2017-05-01 12:06 ` Jiahuan Zhang
2017-03-22 11:07 ` Peter Maydell
2017-03-22 11:33 ` Paolo Bonzini
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