From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
jbeulich@suse.com, keir@xen.org
Cc: roger.pau@citrix.com, david.vrabel@citrix.com, xen-devel@lists.xen.org
Subject: Re: [PATCH] x86/hvm: Provide list of emulated features in HVM CPUID leaf
Date: Tue, 2 Feb 2016 18:30:22 -0500 [thread overview]
Message-ID: <56B13C0E.5070905@oracle.com> (raw)
In-Reply-To: <56B13A2F.3070209@citrix.com>
On 02/02/2016 06:22 PM, Andrew Cooper wrote:
> On 02/02/2016 23:17, Boris Ostrovsky wrote:
>> Hypervisor may choose which features to emulate for HVMlite guests.
>> Guest will query the HVM CPUID leaf to find out what is available.
>>
>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Roger also submitted a patch to do this. However, it is not
> appropriate, so was dropped.
>
> An HVMLite domain should assume there are no emulated devices. The very
> old legacy devices will never be implemented, and any others we care
> about possibly implementing in the future have APCI-based ways of
> indicating support.
OK, so I wasn't the first one to come up with this ;-)
I think for now I mostly care about APIC and for that I can use HW CPUID
bit (which I believe is cleared for HVMlite guests). The trouble is that
I need to present Linux as having APIC (boot code doesn't feel good if
!cpu_has_apic) so I'll need to keep no-APIC emulation private to
Xen-related code. Which is doable.
-boris
next prev parent reply other threads:[~2016-02-02 23:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-02 23:17 [PATCH] x86/hvm: Provide list of emulated features in HVM CPUID leaf Boris Ostrovsky
2016-02-02 23:22 ` Andrew Cooper
2016-02-02 23:30 ` Boris Ostrovsky [this message]
2016-02-03 0:17 ` Andrew Cooper
2016-02-03 8:43 ` Roger Pau Monné
2016-02-03 14:30 ` Boris Ostrovsky
2016-02-03 14:37 ` Andrew Cooper
2016-02-03 14:46 ` Boris Ostrovsky
2016-02-03 15:05 ` Roger Pau Monné
2016-02-03 15:27 ` Boris Ostrovsky
2016-02-03 3:51 ` Tian, Kevin
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