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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Nakajima, Jun" <jun.nakajima@intel.com>,
	Andy Lutomirski <luto@amacapital.net>
Cc: Mathew John <mathewj@microsoft.com>,
	Theodore Ts'o <tytso@mit.edu>,
	John Starks <John.Starks@microsoft.com>,
	kvm list <kvm@vger.kernel.org>, Gleb Natapov <gleb@kernel.org>,
	Niels Ferguson <niels@microsoft.com>,
	Linux Virtualization <virtualization@lists.linux-foundation.org>,
	David Hepkin <davidhep@microsoft.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Jake Oshins <jakeo@microsoft.com>
Subject: Re: Standardizing an MSR or other hypercall to get an RNG seed?
Date: Fri, 19 Sep 2014 18:22:24 +0200	[thread overview]
Message-ID: <541C5840.10205@redhat.com> (raw)
In-Reply-To: <CAL54oT0sibBiLSHf+eajdRgxqs1jgSzdTTCWBUH9M25ZL10EzA@mail.gmail.com>

Il 19/09/2014 18:14, Nakajima, Jun ha scritto:
> For example,
> - CPUID 0x48000001.EAX would return the feature presence (e.g. in
> EBX), and the result in EDX:EAX (if present) at the same time, or
> - CPUID 0x48000001.EAX would return the feature presence only, and
> CPUID 0x48000002.EAX (acts like a hypercall) returns up to 4 32-bit
> values.

The latter is much better, because an "unknown" CPUID will return the
value of the highest leaf below 0x80000000, and conflicts can happen easily.

Paolo

  reply	other threads:[~2014-09-19 16:22 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-18  2:50 Standardizing an MSR or other hypercall to get an RNG seed? Andy Lutomirski
2014-09-18 14:40 ` KY Srinivasan
     [not found] ` <2aa00301e9af4826b5781e01709f81e7@BY2PR0301MB0711.namprd03.prod.outlook.com>
2014-09-18 14:43   ` H. Peter Anvin
2014-09-18 15:38     ` Andy Lutomirski
2014-09-18 15:44       ` Andy Lutomirski
2014-09-18 15:58         ` Paolo Bonzini
2014-09-18 16:36       ` KY Srinivasan
     [not found]       ` <5b9c7dcde3824e49a25f3ee00844b868@BY2PR0301MB0711.namprd03.prod.outlook.com>
2014-09-18 17:13         ` Nakajima, Jun
2014-09-18 17:17           ` Paolo Bonzini
     [not found]           ` <541B13B8.1020006@redhat.com>
2014-09-18 17:20             ` Jake Oshins
2014-09-18 17:20             ` KY Srinivasan
     [not found]             ` <b697ef83ae594d8fb34347339dd52dfa@BY2PR0301MB0711.namprd03.prod.outlook.com>
2014-09-18 17:42               ` Nakajima, Jun
2014-09-18 18:35                 ` Andy Lutomirski
2014-09-18 18:39                   ` H. Peter Anvin
2014-09-18 18:54                     ` Niels Ferguson
2014-09-18 19:03                       ` Andy Lutomirski
2014-09-18 21:54                         ` David Hepkin
     [not found]                         ` <572ba53a2e1e4278823f718a421e2c1d@BY2PR03MB585.namprd03.prod.outlook.com>
2014-09-19  6:04                           ` Paolo Bonzini
2014-09-18 18:58                   ` Paolo Bonzini
2014-09-18 19:07                     ` Andy Lutomirski
2014-09-18 21:21                       ` Nakajima, Jun
2014-09-18 21:35                         ` Andy Lutomirski
2014-09-18 21:46                       ` David Hepkin
     [not found]                       ` <0180a8dfcad746a895755c4374853c16@BY2PR03MB585.namprd03.prod.outlook.com>
2014-09-18 21:57                         ` H. Peter Anvin
2014-09-18 22:07                           ` Andy Lutomirski
2014-09-19  0:49                             ` Nakajima, Jun
     [not found]                             ` <CAL54oT1Q8kABge=t4s5REVWWakboON-6vfszMRkVz=ks_3vRoA@mail.gmail.com>
2014-09-19  1:03                               ` Andy Lutomirski
2014-09-19  1:28                                 ` Andy Lutomirski
     [not found]                                 ` <CALCETrWZ1cF23aT82yGfTKS48d2G+_Od7hEkAzDWzDhqpHNVqA@mail.gmail.com>
2014-09-19 16:14                                   ` Nakajima, Jun
2014-09-19 16:22                                     ` Paolo Bonzini [this message]
2014-09-19 16:40                                     ` H. Peter Anvin
2014-09-19 17:21                                       ` Andy Lutomirski
2014-09-19 17:36                                         ` H. Peter Anvin
2014-09-19 17:39                                           ` Andy Lutomirski
2014-09-19 22:05                                       ` Theodore Ts'o
2014-09-19 22:06                                         ` Andy Lutomirski
2014-09-19 22:57                                           ` Nakajima, Jun
2014-09-19 22:57                                           ` Theodore Ts'o
2014-09-19 23:12                                             ` Andy Lutomirski
2014-09-19 23:29                                               ` H. Peter Anvin
2014-09-19 23:35                                                 ` Theodore Ts'o
2014-09-19 23:41                                                   ` Andy Lutomirski
2014-09-20  0:06                                                   ` H. Peter Anvin
2014-09-19 23:29                                               ` H. Peter Anvin
2014-09-18 22:00                         ` Andy Lutomirski
2014-09-18 22:03                           ` H. Peter Anvin
2014-09-19 16:37                           ` Gleb Natapov
2014-09-19 16:40                             ` H. Peter Anvin
2014-09-19 16:53                               ` Gleb Natapov
2014-09-19 17:08                                 ` H. Peter Anvin
2014-09-19 17:15                                   ` Gleb Natapov
2014-09-19 17:18                                     ` H. Peter Anvin
2014-09-19 17:49                                       ` Gleb Natapov
2014-09-19 18:02                                         ` Andy Lutomirski
2014-09-19 18:12                                           ` Gleb Natapov
2014-09-19 18:20                                             ` Andy Lutomirski
2014-09-19 20:53                                               ` Gleb Natapov
2014-09-22  4:11                                               ` Alok Kataria
2014-09-19 17:18                                     ` H. Peter Anvin
2014-09-19 17:21                                 ` Andy Lutomirski
2014-09-19 17:59                                   ` Gleb Natapov
2014-09-18 18:56                 ` Paolo Bonzini
2014-09-19 18:30 ` Christopher Covington
2014-09-19 18:42   ` Andy Lutomirski
2014-09-19 20:21     ` Nadav Amit
     [not found]     ` <15C8041A-3488-4693-B329-3A9FE77A0CB9@gmail.com>
2014-09-19 20:46       ` Andy Lutomirski
2014-09-19 21:46         ` H. Peter Anvin
2014-09-22 13:31           ` Christopher Covington
2014-09-22 14:17             ` H. Peter Anvin
2014-09-22 14:18               ` H. Peter Anvin
2014-09-22 23:01             ` H. Peter Anvin
2014-09-21 12:39         ` Paolo Bonzini
2014-09-22 13:33     ` Christopher Covington

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