From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Durrant <Paul.Durrant@citrix.com>
Subject: Re: [PATCH RFC] x86/vMSI-X: avoid missing first unmask
	of vectors
Date: Fri, 1 Apr 2016 13:54:31 +0000
Message-ID: <3138a3146ad749b8bc50097878d356cb@AMSPEX02CL03.citrite.net>
References: <56FE583A02000078000E1F0A@prv-mh.provo.novell.com>
 <56FE627802000078000E1F9F@prv-mh.provo.novell.com>
 <b5c10c5929b24b67bdd62dd4ddfe3ff3@AMSPEX02CL03.citrite.net>
 <56FE75D802000078000E201B@prv-mh.provo.novell.com>
 <88fb0367a4ab40f8b36cb1996a0e2f59@AMSPEX02CL03.citrite.net>
 <56FE96FB02000078000E2138@prv-mh.provo.novell.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta6.messagelabs.com ([85.158.143.247])
 by lists.xenproject.org with esmtp (Exim 4.84_2)
 (envelope-from <prvs=892fe319c=Paul.Durrant@citrix.com>)
 id 1alzX0-0001S8-9K
 for xen-devel@lists.xenproject.org; Fri, 01 Apr 2016 13:54:34 +0000
In-Reply-To: <56FE96FB02000078000E2138@prv-mh.provo.novell.com>
Content-Language: en-US
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
 <mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
 <mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Errors-To: xen-devel-bounces@lists.xen.org
Sender: "Xen-devel" <xen-devel-bounces@lists.xen.org>
To: Jan Beulich <JBeulich@suse.com>
Cc: Anthony Perard <anthony.perard@citrix.com>, Andrew Cooper <Andrew.Cooper3@citrix.com>, "Keir (Xen.org)" <keir@xen.org>, Stefano Stabellini <Stefano.Stabellini@citrix.com>, xen-devel <xen-devel@lists.xenproject.org>
List-Id: xen-devel@lists.xenproject.org

PiAtLS0tLU9yaWdpbmFsIE1lc3NhZ2UtLS0tLQo+IEZyb206IEphbiBCZXVsaWNoIFttYWlsdG86
SkJldWxpY2hAc3VzZS5jb21dCj4gU2VudDogMDEgQXByaWwgMjAxNiAxNDo0Mwo+IFRvOiBQYXVs
IER1cnJhbnQKPiBDYzogQW5kcmV3IENvb3BlcjsgQW50aG9ueSBQZXJhcmQ7IFN0ZWZhbm8gU3Rh
YmVsbGluaTsgeGVuLWRldmVsOyBLZWlyCj4gKFhlbi5vcmcpCj4gU3ViamVjdDogUkU6IFtQQVRD
SCBSRkNdIHg4Ni92TVNJLVg6IGF2b2lkIG1pc3NpbmcgZmlyc3QgdW5tYXNrIG9mIHZlY3RvcnMK
PiAKPiA+Pj4gT24gMDEuMDQuMTYgYXQgMTU6MDEsIDxQYXVsLkR1cnJhbnRAY2l0cml4LmNvbT4g
d3JvdGU6Cj4gPj4gRnJvbTogSmFuIEJldWxpY2ggW21haWx0bzpKQmV1bGljaEBzdXNlLmNvbV0K
PiA+PiBTZW50OiAwMSBBcHJpbCAyMDE2IDEyOjIxCj4gPj4gPj4+IE9uIDAxLjA0LjE2IGF0IDEy
OjU2LCA8UGF1bC5EdXJyYW50QGNpdHJpeC5jb20+IHdyb3RlOgo+ID4+ID4+IEZyb206IEphbiBC
ZXVsaWNoIFttYWlsdG86SkJldWxpY2hAc3VzZS5jb21dCj4gPj4gPj4gU2VudDogMDEgQXByaWwg
MjAxNiAxMDo1OQo+ID4+ID4+ID4+PiBPbiAwMS4wNC4xNiBhdCAxMToxNSwgPEpCZXVsaWNoQHN1
c2UuY29tPiB3cm90ZToKPiA+PiA+PiA+IFJlY2VudCBjaGFuZ2VzIHRvIExpbnV4IHJlc3VsdCBp
biB0aGVyZSBqdXN0IGJlaW5nIGEgc2luZ2xlIHVubWFzawo+ID4+ID4+ID4gb3BlcmF0aW9uIHBy
aW9yIHRvIGV4cGVjdGluZyB0aGUgZmlyc3QgaW50ZXJydXB0cyB0byBhcnJpdmUuIEhvd2V2ZXIs
Cj4gPj4gPj4gPiB3ZSd2ZSBoYWQgYSBjaGlja2VuLWFuZC1lZ2cgcHJvYmxlbSBoZXJlOiBRZW11
IGludm9rZXMKPiA+PiA+PiA+IHhjX2RvbWFpbl91cGRhdGVfbXNpX2lycSgpLCB1bHRpbWF0ZWx5
IGxlYWRpbmcgdG8KPiA+PiA+PiA+IG1zaXh0YmxfcHRfcmVnaXN0ZXIoKSwgdXBvbiBzZWVpbmcg
dGhhdCBmaXJzdCB1bm1hc2sgb3BlcmF0aW9uLiBZZXQKPiA+PiA+PiA+IGZvciBtc2l4dGJsX3Jh
bmdlKCkgdG8gcmV0dXJuIHRydWUgKGluIG9yZGVyIHRvIG1zaXh0Ymxfd3JpdGUoKSB0byBnZXQK
PiA+PiA+PiA+IGludm9rZWQgYXQgYWxsKSBtc2l4dGJsX3B0X3JlZ2lzdGVyKCkgbXVzdCBoYXZl
IGNvbXBsZXRlZC4KPiA+PiA+PiA+Cj4gPj4gPj4gPiBEZWFsIHdpdGggdGhpcyBieSBzbm9vcGlu
ZyBzdWl0YWJsZSB3cml0ZXMgaW4gbXNpeHRibF9yYW5nZSgpIGFuZAo+ID4+ID4+ID4gdHJpZ2dl
cmluZyB0aGUgaW52b2NhdGlvbiBvZiBtc2l4X3dyaXRlX2NvbXBsZXRpb24oKSBmcm9tCj4gPj4g
Pj4gPiBtc2l4dGJsX3B0X3JlZ2lzdGVyKCkgd2hlbiB0aGF0IGhhcHBlbnMgaW4gdGhlIGNvbnRl
eHQgb2YgYSBzdGlsbCBpbgo+ID4+ID4+ID4gcHJvZ3Jlc3MgdmVjdG9yIGNvbnRyb2wgZmllbGQg
d3JpdGUuCj4gPj4gPj4gPgo+ID4+ID4+ID4gTm90ZSB0aGF0IHRoZSBzZWVtaW5nbHkgdW5yZWxh
dGVkIGRlbGV0aW9uIG9mIHRoZSByZWR1bmRhbnQKPiA+PiA+PiA+IGlycV9kZXNjLT5tc2lfZGVz
YyBjaGVja3MgaW4gbXNpeHRibF9wdF9yZWdpc3RlcigpIGlzIHRvIG1ha2UgY2xlYXIKPiB0bwo+
ID4+ID4+ID4gYW55IGNvbXBpbGVyIHZlcnNpb24gdXNlZCB0aGF0IHRoZSAibXNpX2Rlc2MiIGxv
Y2FsIHZhcmlhYmxlIGlzbid0Cj4gPj4gPj4gPiBiZWluZyB1c2VkIHVuaW5pdGlhbGl6ZWQuIChE
b2luZyB0aGUgc2FtZSBpbiBtc2l4dGJsX3B0X3VucmVnaXN0ZXIoKQo+IGlzCj4gPj4gPj4gPiBq
dXN0IGZvciBjb25zaXN0ZW5jeSByZWFzb25zLikKPiA+PiA+PiA+Cj4gPj4gPj4gPiBTaWduZWQt
b2ZmLWJ5OiBKYW4gQmV1bGljaCA8amJldWxpY2hAc3VzZS5jb20+Cj4gPj4gPj4gPiAtLS0KPiA+
PiA+PiA+IFRPRE86IEhvdyB0byBkZWFsIHdpdGggUkVQIE1PVlMgdG8gdGhlIE1TSS1YIHRhYmxl
IChpbgo+ID4+IG1zaXh0YmxfcmFuZ2UoKSk/Cj4gPj4gPj4KPiA+PiA+PiBTb21lIG1vcmUgZGV0
YWlsIG9uIHRoZSB0aG91Z2h0cyBJIHNvIGZhciBoYWQgZm9yIHRoaXMgYXNwZWN0Ogo+ID4+ID4+
IEl0IGhhcyBhbHdheXMgYmVlbiBwdXp6bGluZyBtZSB0aGF0IHRoZSBoeXBlcnZpc29yIGRvZXNu
J3QKPiA+PiA+PiBzZWUgX2FsbF8gdGhlIE1TSS1YIHRhYmxlIGFjY2Vzc2VzICh3aGljaCBpcyBh
IHJlc3VsdCBvZiB0aGUKPiA+PiA+PiBhZGRyZXNzZXMgb25seSBnZXR0aW5nIHJlZ2lzdGVyZWQg
dmlhIFhFTl9ET01DVExfYmluZF9wdF9pcnEpOwo+ID4+ID4+IGl0J3MgcXVpdGUgbmF0dXJhbCB0
aGF0IHRoaXMgaXMgYW4gYXQgbGVhc3QgbGF0ZW50IGlzc3VlIHBvc3NpYmx5Cj4gPj4gPj4gY2F1
c2luZyBndWVzdCBtaXNiZWhhdmlvci4gSSBjYW5ub3QsIGhvd2V2ZXIsIGN1cnJlbnRseSBzZWUg
YW55Cj4gPj4gPj4gd2F5IHRvIGFkZHJlc3MgdGhpcyB3aXRob3V0IGFsdGVyaW5nIGJvdGggWGVu
IGFuZCBxZW11LCBzaW5jZSBmb3IKPiA+PiA+PiBYZW4gdG8gc2VlIGFsbCBhY2Nlc3NlcyBpdCB3
b3VsZCBuZWVkIHRvIGJlY29tZSBhd2FyZSBvZiB0aGUKPiA+PiA+PiBHUEEgb2YgdGhlIE1TSS1Y
IHRhYmxlIG11Y2ggZWFybGllciAocmVhZDogYmVmb3JlIHRoZSBkb21haW4KPiA+PiA+PiBhY3R1
YWxseSBzdGFydCwgb3IgYXQgdGhlIGxhdGVzdCB3aGVuIHRoZSBkb21haW4gZmlyc3QgZW5hYmxl
cwo+ID4+ID4+IG1lbW9yeSBkZWNvZGluZyBvbiB0aGUgZGV2aWNlKS4KPiA+PiA+Pgo+ID4+ID4+
IFRoZSBtYXBwaW5nIG9mIHRoZSBNTUlPIEJBUnMgb2YgdGhlIGRldmljZSBpbnRvIGd1ZXN0IG1l
bW9yeSwKPiA+PiA+PiBob3dldmVyLCBpbnRlbnRpb25hbGx5IGV4Y2x1ZGVzIHRoZSBwYWdlKHMp
IGNvdmVyaW5nIHRoZSBNU0ktWAo+ID4+ID4+IHRhYmxlLCBzbyB0aGUgaHlwZXJ2aXNvciBjYW4n
dCBiZWNvbWUgYXdhcmUgb2YgdGhlbSBieSBqdXN0Cj4gPj4gPj4gbG9va2luZyBhdCBkYXRhIGl0
IGdldHMgcHJlc2VudGVkIHRvZGF5LiBIZW5jZSBlaXRoZXIgd2UgbmVlZCB0bwo+ID4+ID4+IGFk
ZCBzb21lIG5ldyBoeXBlcmNhbGwgZm9yIHFlbXUgdG8gaW52b2tlLCBvciB3ZSBuZWVkIHRvIG1h
a2UKPiA+PiA+PiBxZW11IG1hcCB0aGUgZnVsbCBCQVIgcmFuZ2VzLCBmaWx0ZXJpbmcgb3V0IE1T
SS1YIHRhYmxlIHBhZ2VzCj4gPj4gPj4gaW4gdGhlIGh5cGVydmlzb3IgKHVzaW5nIHRob3NlIG1h
cHBpbmcgcmVxdWVzdHMganVzdCB0byBsZWFybiB0aGUKPiA+PiA+PiBHUEEgb2YgdGhlIE1TSS1Y
IHRhYmxlLCB3aXRob3V0IGVudGVyaW5nIHRoZW0gaW50byBQMk0pLgo+ID4+ID4+Cj4gPj4gPj4g
VW5sZXNzIHNvbWVvbmUgY2FuIHRoaW5rIG9mIGEgd2F5IHdoaWNoIGRvZXNuJ3QgcmVxdWlyZSBh
bHRlcmluZwo+ID4+ID4+IGJvdGggcWVtdSBhbmQgWGVuIChjcmVhdGluZyB0aGUgd2VsbCBrbm93
biBjb21wYXRpYmlsaXR5IGlzc3Vlcwo+ID4+ID4+IGJldHdlZW4gdW5tYXRjaGVkIHBhaXJzKSwg
SSB0aGluayB0aGUgcGF0Y2ggYXMgcHJlc2VudGVkIHNob3VsZAo+ID4+ID4+IGJlIG9rYXkgd2l0
aG91dCBoYW5kbGluZyB0aGlzIGNhc2UsIGkuZS4gYmVzdCBwb3NzaWJsZSBlZmZvcnQsIGFuZCBh
Cj4gPj4gPj4gc3Vic2VxdWVudCBjaGFuZ2UgdGhlbiBvdWdodCB0byBiZSB0byBkZWFsIHdpdGgg
dGhpcyBieSBjaGFuZ2luZwo+ID4+ID4+IGJvdGggY29tcG9uZW50cy4gSW4gd2hpY2ggY2FzZSBJ
J2Qgc3VnZ2VzdCB0aGF0IHRoZSBjaGFuZ2UgaGVyZQo+ID4+ID4+IGdvIGludG8gNC43LCBidXQg
dGhlIGZ1bGwgZml4IHdvdWxkIHRoZW4gbGlrZWx5IG5lZWQgZGVmZXJyaW5nIHVudGlsCj4gPj4g
Pj4gNC44Lgo+ID4+ID4KPiA+PiA+IEkgZ3Vlc3MgaXQgY291bGQgYmUgaGFuZGxlZCBlbnRpcmVs
eSBpbiBYZW4gaWYgd2UgYXJlIHdpbGxpbmcgdG8gc25vb3Agb24KPiA+PiA+IFBDSSBjb25maWd1
cmF0aW9uLiBJdCB3b3VsZCBub3QgYmUgdG9vIGhhcmQgdG8gc25vb3AgZ3Vlc3Qgd3JpdGVzIHRv
IHRoZQo+ID4+IEJBUnMKPiA+PiA+IGluIGNvbmZpZyBzcGFjZSBzbyB0aGF0IFhlbiBjYW4ga2Vl
cCB0cmFjayBvZiB3aGVyZSB0aGV5IGFyZS4gU25vb3BpbmcKPiBvbgo+ID4+IHRoZQo+ID4+ID4g
TVNJLVggY2FwYWJpbGl0eSBjb3VsZCB0aGVuIHRlbGwgWGVuIHdoZW4gdG8gc3RhcnQgaW50ZXJw
b3Npbmcgb24gdGhlCj4gdGFibGUsCj4gPj4gPiBhbmQgYWxsb3cgaXQgdG8gZGlzY292ZXIgdGhl
IEdQQSBhdCB0aGF0IHBvaW50ICh2aWEgdGhlIEJJUiBhbmQgb2Zmc2V0Cj4gPj4gPiB2YWx1ZXMp
Lgo+ID4+Cj4gPj4gV2VsbCwgdGhhdCdzIGEgcG9zc2liaWxpdHksIGJ1dCB3b24ndCAtIGFmYWlj
dCAtIHdvcmsgd2l0aG91dCBxZW11J3MKPiA+PiBoZWxwIGF0IGFub3RoZXIgcG9pbnQ6IFNvIGZh
ciB3ZSBkb24ndCBrbm93IHRoZSBndWVzdCdzIFBDSSBidXMKPiA+PiB0b3BvbG9neSwgaGVuY2Ug
d2UgY2FuJ3QgY29ycmVsYXRlIHZCQVIgd3JpdGVzIHdlIG1pZ2h0IHNub29wCj4gPj4gd2l0aCB0
aGUgcGh5c2ljYWwgZGV2aWNlcyB0aGV5IGNvcnJlc3BvbmQgdG8uCj4gPgo+ID4gRG9lcyBYZW4g
bmVlZCB0byBrbm93IHRoYXQgY29ycmVzcG9uZGVuY2UganVzdCB0byB0cmFjayBzdGF0ZT8gSSB0
aG91Z2h0Cj4gdGhlCj4gPiBwcm9ibGVtIGhlcmUgd2FzIHRoYXQgWGVuIGRvZXMgbm90IHNlZSBl
dmVyeSBndWVzdCBhY2Nlc3MgdG8gYW4gTVNJLVgKPiB0YWJsZS4KPiA+IElmIFhlbiBhbHdheXMg
aW50ZXJwb3NlcyBvbiBNU0ktWCB0YWJsZXMgdGhlbiBpdCBjYW4gYXQgbGVhc3QgdHJhY2sgdGhl
IHN0YXRlCj4gPiBvZiB0aGUgZW11bGF0ZWQgdGFibGUsIGV2ZW4gaWYgd2UgZW5kIHVwIGp1c3Qg
Zm9yd2FyZGluZyB0aGUgYWNjZXNzIGZvcgo+IFFFTVUKPiA+IHRvIGhhbmRsZSBhdCBmaXJzdC4g
V2hlbiB0aGUgbWFwcGluZyBpcyBjcmVhdGVkIHRvIHRoZSBhY3R1YWwgaC93IHRhYmxlCj4gdGhl
biwKPiA+IHByZXN1bWFibHksIFhlbidzIGlkZWEgb2Ygc3RhdGUgc2hvdWxkIGNvcnJlc3BvbmQg
dG8gUUVNVSdzLgo+IAo+IEJ1dCBYZW4gZG9lc24ndCBzZWUgdGhlIGd1ZXN0IHZpZXcgb2YgY29u
ZmlnIHNwYWNlLAoKV2VsbCBYZW4gaW50ZXJwb3NlcyBvbiBldmVyeSBzaW5nbGUgY29uZmlnIGN5
Y2xlIHNvIGFyZ3VhYmx5IGl0IHNlZXMgZXhhY3RseSB3aGF0IHRoZSBndWVzdCBzZWVzLgoKPiBh
bmQgdGhlCj4gd2hlcmVhYm91dHMgb2YgdGhlIE1TSS1YIHRhYmxlIGFyZSBpbiByZWFkLW9ubHkg
Y29uZmlnIHNwYWNlIGZpZWxkcwo+IChpLmUuIHNub29waW5nIHdyaXRlcyB0byB0aG9zZSBkb2Vz
bid0IG1ha2Ugc2Vuc2UsIGFzIHRoZSBndWVzdCBtYXkKPiBub3QgZXZlciB3cml0ZSB0aGVtIG9y
IHdyaXRlIGFueXRoaW5nLCB3aGljaCB3b3VsZCBqdXN0IGdldCBkcm9wcGVkCj4gb24gdGhlIGZs
b29yKS4KCkkgd2FzIHRoaW5raW5nIG9mIHNub29waW5nIHRoZSByZWFkcy4gVGhlIGd1ZXN0IGhh
cyB0byBmaW5kIG91dCB3aGVyZSB0aGUgdGFibGUgaXMgYmVmb3JlIGl0IGNhbiB3cml0ZSB0byBp
dCwgcmlnaHQ/IE9yIFhlbiBjb3VsZCBldmVuIHByby1hY3RpdmVseSByZWFkIHRoZSBjYXBhYmls
aXR5IGNoYWluIG9mIGFueSBwY2lkZXYgcmVnaXN0ZXJlZCB3aXRoIGl0LgoKPiAKPiBBbmQgYWRk
aXRpb25hbGx5IG1zaXh0YmxfYWRkcl90b19kZXNjKCkgbmVlZHMgdG8ga25vdyB0aGUgcGh5c2lj
YWwKPiBkZXZpY2UuCj4gCgpZZXMsIGJ1dCBtc2l4dGJsX3JhbmdlKCkgY291bGQgYmUgdHJpdmlh
bGx5IGNoYW5nZWQgdG8gYWNjZXB0IGFueSBhY2Nlc3Mgd2hlcmUgbXNpeHRibF9maW5kX2VudHJ5
KCkgcmV0dXJucyBub24tTlVMTC4gVGhhdCB3b3VsZCBhbGxvdyBtc2l4dGJsX3dyaXRlKCkgdG8g
bWFuaXB1bGF0ZSBlbnRyeS0+ZmxhZ3MgZXZlbiBpZiBtc2l4dGJsX2FkZHJfdG9fZGVzYygpIHJl
dHVybnMgTlVMTC4KCiAgUGF1bAoKPiBKYW4KCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19f
X19fX19fX19fX19fX19fX19fClhlbi1kZXZlbCBtYWlsaW5nIGxpc3QKWGVuLWRldmVsQGxpc3Rz
Lnhlbi5vcmcKaHR0cDovL2xpc3RzLnhlbi5vcmcveGVuLWRldmVsCg==