From: "Jan Beulich" <JBeulich@suse.com>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH 4/5] x86/PV: remove the emulated PIT
Date: Thu, 14 Jan 2016 02:11:29 -0700 [thread overview]
Message-ID: <5697745102000078000C6979@prv-mh.provo.novell.com> (raw)
In-Reply-To: <56975B96.8050607@citrix.com>
>>> On 14.01.16 at 09:25, <roger.pau@citrix.com> wrote:
> El 13/01/16 a les 17.36, Jan Beulich ha escrit:
>>>>> On 13.01.16 at 13:32, <roger.pau@citrix.com> wrote:
>>> The HVMlite series removed the initialization of the emulated PIT for PV
>>> guests, but the handler was still reachable, which means a PV guests can
>>> crash Xen if it pokes at IO ports 0x42, 0x43 or 0x61. Completely remove the
>>> PV PIT handler and move the PIT initialization to HVM guests only.
>>
>> As said on IRC - this is needed for Dom0 to be able to drive the
>> PC speaker. You'll need to provide a fix for the suppressed
>> initialization instead, at least for Dom0. (As an aside, your patch
>> orphans hwdom_pit_access().)
>
> Thanks for the clarification. AFAICT I can leave the usage of
> hwdom_pit_access for Dom0, and completely remove PIT access for DomU, is
> that right?
I don't think so - see the explanation Tim gave on IRC. Afaict the
mention of BIOS here isn't related to a virtual BIOS, but to that
of a passed through graphics card.
Jan
next prev parent reply other threads:[~2016-01-14 9:11 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-13 12:32 [PATCH 0/5] HVMlite: minor fixes and Dom0 preparatory patches Roger Pau Monne
2016-01-13 12:32 ` [PATCH 1/5] xen/elfnotes: initialise phys_entry to UNSET_ADDR32 Roger Pau Monne
2016-01-13 12:46 ` Jan Beulich
2016-01-13 12:52 ` Roger Pau Monné
2016-01-13 13:02 ` Jan Beulich
2016-01-13 13:05 ` Andrew Cooper
2016-01-13 13:08 ` Jan Beulich
2016-01-13 13:10 ` Andrew Cooper
2016-01-13 12:32 ` [PATCH 2/5] libelf: rewrite symtab/strtab loading for Dom0 Roger Pau Monne
2016-01-13 12:32 ` [PATCH 3/5] x86/hvm: don't set the BSP as initialised in hvm_vcpu_initialise Roger Pau Monne
2016-01-13 16:29 ` Jan Beulich
2016-01-13 17:23 ` Roger Pau Monné
2016-01-14 9:07 ` Jan Beulich
2016-01-13 12:32 ` [PATCH 4/5] x86/PV: remove the emulated PIT Roger Pau Monne
2016-01-13 16:36 ` Jan Beulich
2016-01-14 8:25 ` Roger Pau Monné
2016-01-14 9:11 ` Jan Beulich [this message]
2016-01-14 10:59 ` Roger Pau Monné
2016-01-14 12:38 ` Jan Beulich
2016-01-14 14:03 ` Roger Pau Monné
2016-01-14 14:36 ` Jan Beulich
2016-01-13 12:32 ` [PATCH 5/5] x86/HVM: don't setup an intercept handler for IO port 0xcf8 unconditionally Roger Pau Monne
2016-01-13 16:38 ` Jan Beulich
2016-01-13 16:45 ` Andrew Cooper
2016-01-13 16:48 ` Paul Durrant
2016-01-14 8:35 ` Roger Pau Monné
2016-01-14 9:12 ` Jan Beulich
2016-01-14 10:50 ` Andrew Cooper
2016-01-14 11:00 ` Roger Pau Monné
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