From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: How to disable IDE DMA in KVM or in guest OS Date: Thu, 15 May 2014 08:39:59 +0200 Message-ID: <5374613F.3060704@web.de> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="V8tscv29T5WMIcek2kSgCgfAjgbpg6OSW" Cc: kvm To: Arthur Chunqi Li Return-path: Received: from mout.web.de ([212.227.15.4]:61398 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751431AbaEOGka (ORCPT ); Thu, 15 May 2014 02:40:30 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --V8tscv29T5WMIcek2kSgCgfAjgbpg6OSW Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 2014-05-15 07:54, Arthur Chunqi Li wrote: > Hi Jan and there, >=20 > 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 >=20 > I have tried to disable IDE DMA in guest OS booting params as follows: > ide-core.nodma=3D0.0 libata.dma=3D0 ide=3Dnodma ide0=3Dnodma >=20 > But I can also get the followings in dmesg: > [0.533276] ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc040 irq 1= 4 > [0.533641] ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc048 irq 1= 5 >=20 > and I do tracked irq 14 and irq 15 in ioapic_deliver when read/write di= sk. >=20 > How could I totally disable IDE BMDMA from guest's boot time? >=20 > Thanks, > Arthur >=20 --V8tscv29T5WMIcek2kSgCgfAjgbpg6OSW Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlN0YUMACgkQitSsb3rl5xRIFwCg31DkwSkf7wTrNgMpm5O1WwKH c3QAoI4nx2Pb0AHu5n7gKXi5/lVaqVzL =qE5S -----END PGP SIGNATURE----- --V8tscv29T5WMIcek2kSgCgfAjgbpg6OSW--