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From: "Jan Beulich" <JBeulich@suse.com>
To: "Juergen Gross" <jgross@suse.com>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
	<xen-devel@lists.xenproject.org>, <boris.ostrovsky@oracle.com>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [Xen-devel] [PATCH 4/4] xen: select grant interface version
Date: Fri, 15 Sep 2017 07:21:32 -0600	[thread overview]
Message-ID: <59BBEFFC020000780017B8EF@prv-mh.provo.novell.com> (raw)
In-Reply-To: <17e66ddd-cd08-9749-a27b-ac81bf0d3c5d@suse.com>

>>> On 15.09.17 at 15:00, <jgross@suse.com> wrote:
> So I've found the data I've searched in the hypervisor. The maximum
> frame number to expect can be calculated from max_page, mem_hotplug
> and the maximum physical address from cpuid node 0x80000008. If
> CONFIG_BIGMEM isn't defined in Xen it is 16TB max.
> 
> The question is how to present this value to a guest. IMHO something
> like the maximum address width similar to cpuid node 0x80000008
> would be fine. It could be above width for pv guests and the max.
> memory address of the guest for HVM guests (adding a cap for those
> wouldn't be the worst idea, I guess).
> 
> What about a new subop of the xen_version hypercall?

I don't see how that would be a good fit; instead, with the CPUID
similarity you mention, why not provide the information in one of
Xen's CPUID leaves? Otoh I wonder whether returning max_page
from XENMEM_maximum_ram_page is really a good idea, if later
on that value may increase, so perhaps that op should take
mem_hotplug into account.

Jan

  parent reply	other threads:[~2017-09-15 13:21 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-08 14:48 [PATCH 0/4] xen: grant table interface v2 support Juergen Gross
2017-09-08 14:48 ` [PATCH 1/4] xen: re-introduce support for grant v2 interface Juergen Gross
2017-09-08 14:48   ` Juergen Gross
2017-09-12 15:41   ` Boris Ostrovsky
2017-09-12 15:41   ` [Xen-devel] " Boris Ostrovsky
2017-09-12 15:45     ` Juergen Gross
2017-09-12 15:45       ` Juergen Gross
2017-09-08 14:48 ` [PATCH 2/4] xen: limit grant v2 interface to the v1 functionality Juergen Gross
2017-09-08 14:48 ` Juergen Gross
2017-09-12 15:44   ` Boris Ostrovsky
2017-09-12 15:44   ` Boris Ostrovsky
2017-09-12 15:50     ` Juergen Gross
2017-09-12 15:50       ` Juergen Gross
2017-09-12 16:05       ` Boris Ostrovsky
2017-09-12 16:05       ` Boris Ostrovsky
2017-09-12 16:09         ` Juergen Gross
2017-09-12 16:21           ` Boris Ostrovsky
2017-09-12 16:21           ` Boris Ostrovsky
2017-09-12 18:18             ` Juergen Gross
2017-09-12 18:18             ` Juergen Gross
2017-09-13 13:22               ` Boris Ostrovsky
2017-09-13 13:38                 ` Juergen Gross
2017-09-13 13:50                   ` Boris Ostrovsky
2017-09-13 13:50                     ` Boris Ostrovsky
2017-09-13 14:45                     ` Juergen Gross
2017-09-13 16:20                       ` Boris Ostrovsky
2017-09-13 16:20                       ` Boris Ostrovsky
2017-09-14  8:13                         ` Juergen Gross
2017-09-14  8:13                         ` Juergen Gross
2017-09-13 14:45                     ` Juergen Gross
2017-09-13 13:38                 ` Juergen Gross
2017-09-13 13:22               ` Boris Ostrovsky
2017-09-12 16:09         ` Juergen Gross
2017-09-08 14:48 ` [PATCH 3/4] xen: add grant interface version dependent constants to gnttab_ops Juergen Gross
2017-09-12 16:02   ` Boris Ostrovsky
2017-09-12 16:02   ` Boris Ostrovsky
2017-09-08 14:48 ` Juergen Gross
2017-09-08 14:48 ` [PATCH 4/4] xen: select grant interface version Juergen Gross
2017-09-08 14:48 ` Juergen Gross
2017-09-12 16:21   ` Boris Ostrovsky
2017-09-12 16:21   ` [Xen-devel] " Boris Ostrovsky
2017-09-12 18:54   ` Andrew Cooper
2017-09-13  9:23     ` Juergen Gross
2017-09-15 13:00       ` Juergen Gross
2017-09-15 13:00       ` [Xen-devel] " Juergen Gross
2017-09-15 13:21         ` Jan Beulich
2017-09-15 13:21         ` Jan Beulich [this message]
     [not found]         ` <59BBEFFC020000780017B8EF@suse.com>
2017-09-15 13:27           ` Juergen Gross
2017-09-15 13:27           ` [Xen-devel] " Juergen Gross
2017-09-13  9:23     ` Juergen Gross
2017-09-12 18:54   ` Andrew Cooper

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