From: Jan Kiszka <jan.kiszka@web.de>
To: Arthur Chunqi Li <yzt356@gmail.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: Re: How to disable IDE DMA in KVM or in guest OS
Date: Thu, 15 May 2014 08:39:59 +0200 [thread overview]
Message-ID: <5374613F.3060704@web.de> (raw)
In-Reply-To: <CABpY8MK94Eex9tG=qJXx8NaAzqeQbt5Kf36jFb56nb2B03ui-g@mail.gmail.com>
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On 2014-05-15 07:54, Arthur Chunqi Li wrote:
> Hi Jan and there,
>
> I want to disable IDE BMDMA in Qemu/KVM and let guest OS uses only PIO
> mode. Are there any configurations in Qemu or KVM to disable the
> hardware support of DMA?
Not that I know. These features are built into the chipsets we emulate,
and there seems to be no option to disable them. Maybe the isapc will
not expose DMA capabilities - but will also lack a lot of other things
like PCI...
Jan
>
> I have tried to disable IDE DMA in guest OS booting params as follows:
> ide-core.nodma=0.0 libata.dma=0 ide=nodma ide0=nodma
>
> But I can also get the followings in dmesg:
> [0.533276] ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc040 irq 14
> [0.533641] ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc048 irq 15
>
> and I do tracked irq 14 and irq 15 in ioapic_deliver when read/write disk.
>
> How could I totally disable IDE BMDMA from guest's boot time?
>
> Thanks,
> Arthur
>
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next prev parent reply other threads:[~2014-05-15 6:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-15 5:54 How to disable IDE DMA in KVM or in guest OS Arthur Chunqi Li
2014-05-15 6:39 ` Jan Kiszka [this message]
2014-05-15 6:55 ` Arthur Chunqi Li
2014-05-15 6:58 ` Jan Kiszka
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