From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Subject: RE: [PATCH v6] x86: load FPU registers on return to userland Date: Wed, 16 Jan 2019 10:18:41 +0000 Message-ID: References: <20190109114744.10936-1-bigeasy@linutronix.de> <2e396dbcbb1c4cc191b4208626baed07@AcuMS.aculab.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 Cc: Sebastian Andrzej Siewior , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , Paolo Bonzini , =?utf-8?B?UmFkaW0gS3LEjW3DocWZ?= , "kvm@vger.kernel.org" , Rik van Riel , Dave Hansen To: 'Andy Lutomirski' , Dave Hansen , "Jason A. Donenfeld" Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org RnJvbTogQW5keSBMdXRvbWlyc2tpDQo+IFNlbnQ6IDE1IEphbnVhcnkgMjAxOSAyMDoyNw0KPiBP biBUdWUsIEphbiAxNSwgMjAxOSBhdCAxMTo0NiBBTSBEYXZlIEhhbnNlbiA8ZGF2ZS5oYW5zZW5A aW50ZWwuY29tPiB3cm90ZToNCj4gPg0KPiA+IE9uIDEvMTUvMTkgNDo0NCBBTSwgRGF2aWQgTGFp Z2h0IHdyb3RlOg0KPiA+ID4gT25jZSB0aGlzIGlzIGRvbmUgaXQgbWlnaHQgYmUgd29ydGggd2hp bGUgYWRkaW5nIGEgcGFyYW1ldGVyIHRvDQo+ID4gPiBrZXJuZWxfZnB1X2JlZ2luKCkgdG8gcmVx dWVzdCB0aGUgcmVnaXN0ZXJzIG9ubHkgd2hlbiB0aGV5IGRvbid0DQo+ID4gPiBuZWVkIHNhdmlu Zy4NCj4gPiA+IFRoaXMgd291bGQgYmVuZWZpdCBjb2RlIHBhdGhzIHdoZXJlIHRoZSBnYWlucyBh cmUgcmVhc29uYWJsZSBidXQgbm90IG1hc3NpdmUuDQo+ID4gPg0KPiA+ID4gVGhlIHJldHVybiB2 YWx1ZSBmcm9tIGtlcm5lbF9mcHVfYmVnaW4oKSBvdWdodCB0byBpbmRpY2F0ZSB3aGljaA0KPiA+ ID4gcmVnaXN0ZXJzIGFyZSBhdmFpbGFibGUgLSBub25lLCBTU0UsIFNTRTIsIEFWWCwgQVZYNTEy IGV0Yy4NCj4gPiA+IFNvIGNvZGUgY2FuIHVzZSBhbiBhcHByb3ByaWF0ZSBpbXBsZW1lbnRhdGlv bi4NCj4gPiA+IChJJ3ZlIG5vdCBsb29rZWQgdG8gc2VlIGlmIHRoaXMgaXMgYWxyZWFkeSB0aGUg Y2FzZSEpDQo+ID4NCj4gPiBZZWFoLCBpdCB3b3VsZCBiZSBzYW5lIHRvIGhhdmUgYm90aCBhIG1h c2sgcGFzc2VkLCBhbmQgcmV0dXJuZWQsIHNheToNCj4gPg0KPiA+ICAgICAgICAgZ290ID0ga2Vy bmVsX2ZwdV9iZWdpbihYRkVBVFVSRV9NQVNLX0FWWDUxMiwgTk9fWFNBVkVfQUxMT1dFRCk7DQoN CllvdSBjb3VsZCBtZXJnZSB0aGUgdHdvIGFyZ3VtZW50cy4NCg0KPiA+ICAgICAgICAgaWYgKGdv dCA9PSBYRkVBVFVSRV9NQVNLX0FWWDUxMikNCg0KCWdvdCAmIFhGRUFUVVJFX01BU0tfQVZYNTEy DQoNCj4gPiAgICAgICAgICAgICAgICAgZG9fYXZ4XzUxMl9nb28oKTsNCj4gPiAgICAgICAgIGVs c2UNCj4gPiAgICAgICAgICAgICAgICAgZG9faW50ZWdlcl9nb28oKTsNCj4gPg0KPiA+ICAgICAg ICAga2VybmVsX2ZwdV9lbmQoZ290KQ0KPiA+DQo+ID4gVGhlbiwga2VybmVsX2ZwdV9iZWdpbigp IGNhbiBhY3R1YWxseSB3b3JrIHdpdGhvdXQgZXZlbiAqZG9pbmcqIGFuIFhTQVZFOg0KPiA+DQo+ ID4gICAgICAgICAvKiBEbyB3ZSBoYXZlIHRvIHNhdmUgc3RhdGUgZm9yIGFueXRoaW5nIGluICdh c2tfbWFzayc/ICovDQo+ID4gICAgICAgICBpZiAoYWxsX3N0YXRlc19hcmVfaW5pdChhc2tfbWFz aykpDQo+ID4gICAgICAgICAgICAgICAgIHJldHVybiBhc2tfbWFzazsNCg0KSXQgYWxtb3N0IGNl cnRhaW5seSBuZWVkcyB0byBkaXNhYmxlIHByZS1lbXB0aW9uIC0gdGhlcmUgaXNuJ3QgYW5vdGhl cg0KZnB1IHNhdmUgYXJlYS4NCg0KPiA+DQo+ID4gVGhlbiBrZXJuZWxfZnB1X2VuZCgpIGp1c3Qg bmVlZHMgdG8gemVybyBvdXQgKHJlLWluaXQpIHRoZSBzdGF0ZSwgd2hpY2gNCj4gPiBpdCBjYW4g ZG8gd2l0aCBYUlNUT1JTIGFuZCBhIGNhcmVmdWwgY29tYmluYXRpb24gb2YgWFNUQVRFX0JWIGFu ZCB0aGUNCj4gPiByZXF1ZXN0ZWQgZmVhdHVyZSBiaXRtYXAgKFJGQk0pLg0KPiA+DQo+ID4gVGhp cyBpcyBhbGwganVzdCBvcHRpbWl6YXRpb24sIHRob3VnaC4NCj4gDQo+IEkgZG9uJ3QgdGhpbmsg d2UnZCBldmVyIHdhbnQga2VybmVsX2ZwdV9lbmQoKSB0byByZXN0b3JlIGFueXRoaW5nLA0KPiBy aWdodD8gIEknbSBhIGJpdCBjb25mdXNlZCBhcyB0byB3aGVuIHRoaXMgb3B0aW1pemF0aW9uIHdv dWxkIGFjdHVhbGx5DQo+IGJlIHVzZWZ1bC4NCg0KVGhlIHVzZXIgcmVnaXN0ZXIgcmVzdG9yZSBp cyBkZWZlcnJlZCB0byAncmV0dXJuIHRvIHVzZXInLg0KDQpXaGF0IHlvdSBuZWVkIHRvIGVuc3Vy ZSBpcyB0aGF0IHRoZSBrZXJuZWwgdmFsdWVzIG5ldmVyIGxlYWsgb3V0DQp0byB1c2Vyc3BhY2Uu DQoNCklTVFIgdGhlcmUgaXMgYSBmbGFnIHRoYXQgc2F5cyB0aGF0IGFsbCB0aGUgQVZYIHJlZ2lz dGVycyBhcmUgemVybw0KKFhTQVZFIHdyaXRlcyBvbmUsIEkgY2FuJ3QgcmVtZW1iZXIgaWYgaXQg aXMgcmVhZGFibGUpLg0KSWYgdGhlIHJlZ2lzdGVycyBhcmUgYWxsIHplcm8gSSB0aGluayB0aGUg a2VybmVsIGNvZGUgY2FuIHVzZSB0aGVtDQpldmVuIGlmIHRoZXkgYXJlICdsaXZlJyAtIHByb3Zp ZGVkIHRoZXkgZ2V0IHplcm9lZCBhZ2FpbiBiZWZvcmUNCnJldHVybiB0byB1c2VyLg0KSSBhbHNv IGNhbid0IHJlbWVtYmVyIHdoZXRoZXIgdGhlIGZwdSBmbGFncyByZWdpc3RlciBpcyBzZXQgYnkg QVZYDQppbnN0cnVjdGlvbnMgLSBJIGtub3cgdGhhdCBpcyBhIHBpdGEgdG8gcmVjb3Zlci4NCg0K QWxzbyBhcmUgYWxsIHN5c3RlbSBjYWxscyBlbnRlcmVkIHZpYSBhc20gc3R1YnMgdGhhdCBsb29r IGxpa2UgcmVhbCBmdW5jdGlvbnM/DQooSSB0aGluayBJJ3ZlIHNlZW4gaW5saW5lIHN5c3RlbSBj YWxscyBpbiBhIGxpbnV4IGJpbmFyeSAtIGJ1dCB0aGF0IHdhcyBhDQpsb25nIHRpbWUgYWdvLikN CklmIHRoYXQgYXNzdW1wdGlvbiBjYW4gYmUgbWFkZSB0aGVuIGJlY2F1c2UgdGhlIEFWWCByZWdp c3RlcnMgYXJlIGFsbA0KY2FsbGVyLXNhdmVkIHRoZXkgYXJlIG5vdCAnbGl2ZScgb24gc3lzdGVt IGNhbGwgZW50cnkgc28gY2FuIGJlIHplcm9lZA0KYW5kIG5lZWQgbm90IGJlIHNhdmVkIG9uIGEg Y29udGV4dCBzd2l0Y2guDQooVGhleSBzdGlsbCBuZWVkIHNhdmluZyBpZiB0aGUga2VybmVsIGlz IGVudGVyZWQgYnkgdHJhcCBvciBpbnRlcnJ1cHQuKQ0KDQoJRGF2aWQNCg0KLQ0KUmVnaXN0ZXJl ZCBBZGRyZXNzIExha2VzaWRlLCBCcmFtbGV5IFJvYWQsIE1vdW50IEZhcm0sIE1pbHRvbiBLZXlu ZXMsIE1LMSAxUFQsIFVLDQpSZWdpc3RyYXRpb24gTm86IDEzOTczODYgKFdhbGVzKQ0K