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Re: [Qemu-devel] Guest application reading from pl011 without device dri
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] Guest application reading from pl011 without device driver |
Date: |
Wed, 22 Mar 2017 10:37:50 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 |
On 22/03/2017 09:48, Jiahuan Zhang wrote:
>
>
> On 22 March 2017 at 09:40, Paolo Bonzini <address@hidden
> <mailto:address@hidden>> wrote:
>
>
> > > 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.
>
>
> Hi, I am trying to use a Windows socket for serial redirection instead
> of Windows named pipe.
> What do you mean "the equivalent of 'select'"?
A function that lets a process sleep until data is available on the
socket. The solution is to rewrite Windows chardev handling in QEMU to
use threads or overlapped I/O.
Paolo
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, (continued)
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/21
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/21
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Peter Maydell, 2017/03/21
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/21
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Peter Maydell, 2017/03/21
- Message not available
- Message not available
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/21
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Peter Maydell, 2017/03/21
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/21
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Paolo Bonzini, 2017/03/22
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/22
- Re: [Qemu-devel] Guest application reading from pl011 without device driver,
Paolo Bonzini <=
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/22
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Paolo Bonzini, 2017/03/22
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/23
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Paolo Bonzini, 2017/03/23
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/23
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Paolo Bonzini, 2017/03/23
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/24
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Jiahuan Zhang, 2017/03/24
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Peter Maydell, 2017/03/22
- Re: [Qemu-devel] Guest application reading from pl011 without device driver, Paolo Bonzini, 2017/03/22