From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:55965) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QxmC6-0002DY-IZ for qemu-devel@nongnu.org; Sun, 28 Aug 2011 16:43:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QxmC4-0001vD-FG for qemu-devel@nongnu.org; Sun, 28 Aug 2011 16:43:02 -0400 Received: from fmmailgate01.web.de ([217.72.192.221]:39816) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QxmC4-0001ui-2a for qemu-devel@nongnu.org; Sun, 28 Aug 2011 16:43:00 -0400 Message-ID: <4E5AA849.5090400@web.de> Date: Sun, 28 Aug 2011 22:42:49 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <4B17C12B.4020300@linux.vnet.ibm.com> <4B17CC5F.20101@redhat.com> <4E59F15E.6000201@redhat.com> In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig0A424FB82F43DE6A2D3E20B7" Sender: jan.kiszka@web.de Subject: [Qemu-devel] HPET configuration in Seabios (was: Re: windows workload: many ept_violation and mmio exits) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf , Kevin O'Connor Cc: Andrew Theurer , "kvm@vger.kernel.org list" , Gleb Natapov , seabios , ya su , QEMU Developers , Avi Kivity This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig0A424FB82F43DE6A2D3E20B7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2011-08-28 20:54, Alexander Graf wrote: >=20 > On 28.08.2011, at 02:42, Avi Kivity wrote: >=20 >> On 08/26/2011 08:32 AM, ya su wrote: >>> hi,Avi: >>> >>> I met the same problem, tons of hpet vm_exits(vector 209, fault >>> address is in the guest vm's hpet mmio range), even I disable hpet >>> device in win7 guest vm, it still produce a larget amount of vm_exits= >>> when trace-cmd ; I add -no-hpet to start the vm, it still has HPET >>> device inside VM. >>> >>> Does that means the HPET device in VM does not depend on the >>> emulated hpet device in qemu-kvm? Is there any way to disable the VM >>> HPET device to prevent so many vm_exits? Thansk. >>> >> >> Looks like a bug to me. >=20 > IIRC disabling the HPET device doesn't remove the entry from the DSDT, = no? So the guest OS might still think it's there while nothing responds (= read returns -1). Exactly. We have a fw_cfg interface in place for quite a while now (though I wonder how the firmware is supposed to tell -no-hpet apart from QEMU versions that don't provide this data - both return count =3D 255), but SeaBios still exposes one HPET block at a hard-coded address unconditionally. There was quite some discussion about the corresponding Seabios patches back then but apparently no consensus was found. Re-reading it, I think Kevin asked for passing the necessary DSDT fragments from QEMU to the firmware instead of using a new, proprietary fw_cfg format. Is that still the key requirement for any patch finally fixing this bug? Jan --------------enig0A424FB82F43DE6A2D3E20B7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk5aqFEACgkQitSsb3rl5xSkyQCfTTRWt2Y+L0PW+zERFys9iLDP wTYAnjyXAWxlBo9kuyBDKUkBgVdkBZCj =LSsG -----END PGP SIGNATURE----- --------------enig0A424FB82F43DE6A2D3E20B7--