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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: "Liu, Jing2" <jing2.liu@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Jing Liu <jing2.liu@linux.intel.com>,
	"seanjc@google.com" <seanjc@google.com>,
	"Cooper, Andrew" <andrew.cooper3@citrix.com>,
	"Bae, Chang Seok" <chang.seok.bae@intel.com>
Subject: Re: Thoughts of AMX KVM support based on latest kernel
Date: Wed, 17 Nov 2021 13:53:42 +0100	[thread overview]
Message-ID: <c7d87723-5533-257f-fbf0-ecd3a0b96602@redhat.com> (raw)
In-Reply-To: <BN9PR11MB5433D6A1368904D9B748846B8C9A9@BN9PR11MB5433.namprd11.prod.outlook.com>

On 11/17/21 11:15, Tian, Kevin wrote:
> We are not sure whether such trick is worthwhile, since a sane
> guest shouldn't set XFD[AMX]=1 before storing the AMX state. This
> is why we want to seek SDM change to mark out that the software
> should not assume XTILEDATA is still valid when XFD[AMX]=1.

Okay, I just don't want it to be called out as virtualization specific.

It doesn't have to happen in current processors, but it should be 
architecturally valid behavior to clear the processor's state as soon as 
a bit in XFD is set to 1.

Paolo


  parent reply	other threads:[~2021-11-17 12:53 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-10 13:01 Thoughts of AMX KVM support based on latest kernel Liu, Jing2
2021-11-16 12:18 ` Thomas Gleixner
2021-11-16 16:05   ` Sean Christopherson
2021-11-16 18:55     ` Thomas Gleixner
2021-11-16 19:49       ` Paolo Bonzini
2021-11-16 20:14         ` Sean Christopherson
2021-11-16 20:36         ` Thomas Gleixner
2021-11-16 22:11           ` Nakajima, Jun
2021-11-17  7:39           ` Paolo Bonzini
2021-11-16 20:12       ` Sean Christopherson
2021-11-16 23:35         ` Thomas Gleixner
2021-11-16 19:20 ` Thomas Gleixner
2021-11-17  4:52   ` Nakajima, Jun
2021-11-17  7:31     ` Paolo Bonzini
2021-11-17 10:15       ` Tian, Kevin
2021-11-17 12:24         ` Thomas Gleixner
2021-11-17 12:53         ` Paolo Bonzini [this message]
2021-11-18 23:17           ` Nakajima, Jun
2021-11-19 10:13             ` Thomas Gleixner
2021-11-19 15:41               ` Nakajima, Jun
2021-12-08  0:50                 ` Rewording of Setting IA32_XFD[18] (Re: Thoughts of AMX KVM support based on latest kernel) Nakajima, Jun
2021-12-08 13:57                   ` Paolo Bonzini
2021-12-10 21:53                   ` Thomas Gleixner

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