From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Razvan Cojocaru <rcojocaru@bitdefender.com>
Cc: Jan Beulich <JBeulich@suse.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: Getting the XSAVE size from userspace
Date: Thu, 5 Nov 2015 10:49:33 +0000 [thread overview]
Message-ID: <563B343D.4090707@citrix.com> (raw)
In-Reply-To: <563B40A202000078000B211F@prv-mh.provo.novell.com>
On 05/11/15 10:42, Jan Beulich wrote:
>>>> On 05.11.15 at 10:52, <rcojocaru@bitdefender.com> wrote:
>> I need to get the XSAVE size from userspace. The easiest way seems to be
>> to use the XEN_DOMCTL_getvcpuextstate hypercall, but that hypercall is
>> not public / there's no xenctrl.h wrapper for it.
> Before going into any detail of the rest of your mail - any reason you
> can't just consult CPUID output?
It depends on precisely what you want.
CPUID.0xD[0].ecx gives you the maximum xsave area on this processor
CPUID.0xD[0].ebx gives you the current size for the value in xcr0, but
that is not very useful from userspace.
~Andrew
next prev parent reply other threads:[~2015-11-05 10:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-05 9:52 Getting the XSAVE size from userspace Razvan Cojocaru
2015-11-05 10:42 ` Jan Beulich
2015-11-05 10:47 ` Razvan Cojocaru
2015-11-05 10:52 ` Jan Beulich
2015-11-05 10:53 ` Andrew Cooper
2015-11-05 10:49 ` Andrew Cooper [this message]
2015-11-05 10:51 ` Jan Beulich
2015-11-05 11:35 ` Andrei LUTAS
2015-11-05 11:44 ` Andrew Cooper
2015-11-05 12:26 ` Razvan Cojocaru
2015-11-05 14:05 ` Andrew Cooper
2015-11-05 14:13 ` Razvan Cojocaru
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