From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
<david.vrabel@citrix.com>, <JGross@suse.com>
Cc: <xen-devel@lists.xenproject.org>, <linux-kernel@vger.kernel.org>,
<roger.pau@citrix.com>, Jan Beulich <jbeulich@suse.com>
Subject: Re: [Xen-devel] [PATCH 8/8] xen/pvh: Enable CPU hotplug
Date: Thu, 27 Oct 2016 16:00:26 +0100 [thread overview]
Message-ID: <9e8a05ce-851f-ed9e-c5af-ad9cc84876a1@citrix.com> (raw)
In-Reply-To: <846901a2-06c1-931f-9933-bda4696e2e40@oracle.com>
On 27/10/16 15:25, Boris Ostrovsky wrote:
>
>
> On 10/14/2016 03:01 PM, Boris Ostrovsky wrote:
>> On 10/14/2016 02:41 PM, Andrew Cooper wrote:
>>> On 14/10/16 19:05, Boris Ostrovsky wrote:
>>>> PVH guests don't receive ACPI hotplug interrupts and therefore
>>>> need to monitor xenstore for CPU hotplug event.
>>> Why not? If they don't, they should. As we are providing ACPI anyway,
>>> we should provide all bits of it.
>>
>> We don't have IOAPIC, which is how these interrupts are typically
>> delivered. I suppose we might be able to specify it as something else.
>>
>> I'll look into this.
>
>
> (+Jan)
>
> Yes, we can do this. The main issue is how to deal with event
> registers (i.e FADT.x_pm1a_evt_blk) and AML's PRST region (which
> specifies online CPU map).
>
> Currently these are accessed via IO space and are handled by qemu.
>
> There are a couple of ways to deal with this that I can see.
>
> 1. We can implement ioreq handling in the hypervisor, there are only a
> few addresses that need handling.
>
> 2. We can implement those registers in memory space and have libxl
> update them them on a hotplug command. This appears to be possible
> because these registers mostly just consume writes without side
> effects so they can be simple memory locations. The one exception is
> updating status bits (they are cleared by writing 1s) but I think we
> can do this from the AML.
>
> Other than that the only other thing is setting up an event channel
> between the toolstack and the guest (either via xenstore or perhaps by
> having a reserved port for SCI).
>
> I have a prototype with (2) (except for the bit clearing part) but I
> want to hear comments on this approach before I write proper patches.
Xen already deals with 1 for HVM guests. We should do the same for PVH
guests as well.
-1 to anything involving looping a PVH dom0 back around to some entity
running inside dom0.
~Andrew
~Andrew
next prev parent reply other threads:[~2016-10-27 15:00 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-14 18:05 [PATCH 0/8] PVH v2 support Boris Ostrovsky
2016-10-14 18:05 ` [PATCH 1/8] xen/x86: Remove PVH support Boris Ostrovsky
2016-10-14 18:31 ` [Xen-devel] " Konrad Rzeszutek Wilk
2016-10-18 13:46 ` Juergen Gross
2016-10-18 14:45 ` Boris Ostrovsky
2016-10-18 15:33 ` Juergen Gross
2016-10-18 15:42 ` Boris Ostrovsky
2016-10-14 18:05 ` [PATCH 2/8] x86/head: Refactor 32-bit pgtable setup Boris Ostrovsky
2016-10-14 18:31 ` hpa
2016-10-14 18:44 ` Boris Ostrovsky
2016-10-14 19:04 ` hpa
2016-10-14 19:18 ` Boris Ostrovsky
2016-10-31 12:33 ` Boris Ostrovsky
2016-12-01 15:33 ` Boris Ostrovsky
2016-12-02 9:45 ` Ingo Molnar
2016-12-02 14:04 ` Boris Ostrovsky
2016-12-02 16:08 ` Ingo Molnar
2016-12-02 17:52 ` hpa
2016-12-02 19:49 ` Boris Ostrovsky
2016-12-03 5:49 ` Ingo Molnar
2016-12-03 6:36 ` hpa
2016-10-14 18:05 ` [PATCH 3/8] xen/pvh: Import PVH-related Xen public interfaces Boris Ostrovsky
2016-10-14 18:34 ` [Xen-devel] " Konrad Rzeszutek Wilk
2016-10-21 10:58 ` Juergen Gross
2016-10-14 18:05 ` [PATCH 4/8] xen/pvh: Bootstrap PVH guest Boris Ostrovsky
2016-10-14 18:38 ` [Xen-devel] " Andrew Cooper
2016-10-14 18:55 ` Boris Ostrovsky
2016-10-14 19:12 ` Andrew Cooper
2016-10-14 19:14 ` Konrad Rzeszutek Wilk
2016-10-14 19:34 ` Boris Ostrovsky
2016-10-14 18:05 ` [PATCH 5/8] xen/pvh: Prevent PVH guests from using PIC, RTC and IOAPIC Boris Ostrovsky
2016-10-14 19:16 ` [Xen-devel] " Konrad Rzeszutek Wilk
2016-10-14 19:37 ` Boris Ostrovsky
2016-10-26 10:42 ` Roger Pau Monné
2016-10-26 14:50 ` Boris Ostrovsky
2016-10-26 15:18 ` Roger Pau Monné
2016-10-26 16:06 ` Boris Ostrovsky
2016-10-14 18:05 ` [PATCH 6/8] xen/pvh: Initialize grant table for PVH guests Boris Ostrovsky
2016-10-14 19:19 ` [Xen-devel] " Konrad Rzeszutek Wilk
2016-10-14 19:43 ` Boris Ostrovsky
2016-10-14 19:51 ` Konrad Rzeszutek Wilk
2016-10-14 20:02 ` Boris Ostrovsky
2016-10-18 16:08 ` Juergen Gross
2016-10-18 16:40 ` Boris Ostrovsky
2016-10-19 5:47 ` Juergen Gross
2016-10-14 18:05 ` [PATCH 7/8] xen/pvh: PVH guests always have PV devices Boris Ostrovsky
2016-10-14 19:17 ` [Xen-devel] " Konrad Rzeszutek Wilk
2016-10-18 15:54 ` Juergen Gross
2016-10-14 18:05 ` [PATCH 8/8] xen/pvh: Enable CPU hotplug Boris Ostrovsky
2016-10-14 18:41 ` [Xen-devel] " Andrew Cooper
2016-10-14 19:01 ` Boris Ostrovsky
2016-10-27 14:25 ` Boris Ostrovsky
2016-10-27 15:00 ` Andrew Cooper [this message]
2016-10-27 16:23 ` Boris Ostrovsky
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