From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Subject: Re: [PATCH v3 1/3] x86/ldt: Make modify_ldt synchronous Date: Fri, 24 Jul 2015 21:52:01 -0700 Message-ID: References: <049fdbab8ae2ecac1c8b40ecd558e9df45ccd5d3.1437592883.git.luto@kernel.org> <20150724152955.GC21441@nazgul.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20150724152955.GC21441@nazgul.tnic> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Borislav Petkov Cc: "security@kernel.org" , Jan Beulich , Peter Zijlstra , Andrew Cooper , X86 ML , "linux-kernel@vger.kernel.org" , Steven Rostedt , xen-devel , stable , Andy Lutomirski , Sasha Levin , Boris Ostrovsky List-Id: xen-devel@lists.xenproject.org T24gRnJpLCBKdWwgMjQsIDIwMTUgYXQgODoyOSBBTSwgQm9yaXNsYXYgUGV0a292IDxicEBhbGll bjguZGU+IHdyb3RlOgo+IExldCBpdCBzdGljayBvdXQ6Cj4KPiAgICAgICAgIGlmICghY3B1bWFz a19lcXVhbChtbV9jcHVtYXNrKGN1cnJlbnRfbW0pLCBjcHVtYXNrX29mKHNtcF9wcm9jZXNzb3Jf aWQoKSkpKQo+ICAgICAgICAgICAgICAgICBzbXBfY2FsbF9mdW5jdGlvbihmbHVzaF9sZHQsIGN1 cnJlbnRfbW0sIDEpOwoKSSBzZWUgeW91ciB3aWRlIHRlcm1pbmFsIGFuZCByYWlzZSB5b3UgYSBj b21wbGV0ZSByZXdyaXRlIG9mIHRoYXQKZnVuY3Rpb24uICBTaWdoLCB3aHkgZGlkIEkgYXNzdW1l IHRoZSBvbGQgY29kZSB3YXMgdGhlIHJpZ2h0IHdheSB0byBkbwppdD8KCj4+ICAjZW5kaWYKPj4g LSAgICAgfQo+PiAtICAgICBpZiAob2xkc2l6ZSkgewo+PiAtICAgICAgICAgICAgIHBhcmF2aXJ0 X2ZyZWVfbGR0KG9sZGxkdCwgb2xkc2l6ZSk7Cj4+IC0gICAgICAgICAgICAgaWYgKG9sZHNpemUg KiBMRFRfRU5UUllfU0laRSA+IFBBR0VfU0laRSkKPj4gLSAgICAgICAgICAgICAgICAgICAgIHZm cmVlKG9sZGxkdCk7Cj4+IC0gICAgICAgICAgICAgZWxzZQo+PiAtICAgICAgICAgICAgICAgICAg ICAgcHV0X3BhZ2UodmlydF90b19wYWdlKG9sZGxkdCkpOwo+PiAtICAgICB9Cj4+IC0gICAgIHJl dHVybiAwOwo+PiArICAgICBwcmVlbXB0X2VuYWJsZSgpOwo+PiAgfQo+Pgo+PiAtc3RhdGljIGlu bGluZSBpbnQgY29weV9sZHQobW1fY29udGV4dF90ICpuZXcsIG1tX2NvbnRleHRfdCAqb2xkKQo+ PiArc3RhdGljIHZvaWQgZnJlZV9sZHRfc3RydWN0KHN0cnVjdCBsZHRfc3RydWN0ICpsZHQpCj4+ ICB7Cj4+IC0gICAgIGludCBlcnIgPSBhbGxvY19sZHQobmV3LCBvbGQtPnNpemUsIDApOwo+PiAt ICAgICBpbnQgaTsKPj4gLQo+PiAtICAgICBpZiAoZXJyIDwgMCkKPj4gLSAgICAgICAgICAgICBy ZXR1cm4gZXJyOwo+PiAtCj4+IC0gICAgIGZvciAoaSA9IDA7IGkgPCBvbGQtPnNpemU7IGkrKykK Pj4gLSAgICAgICAgICAgICB3cml0ZV9sZHRfZW50cnkobmV3LT5sZHQsIGksIG9sZC0+bGR0ICsg aSAqIExEVF9FTlRSWV9TSVpFKTsKPj4gLSAgICAgcmV0dXJuIDA7Cj4+ICsgICAgIGlmICh1bmxp a2VseShsZHQpKSB7Cj4KPiBTYXZlIGFuIGluZGVudGF0aW9uIGxldmVsOgo+Cj4gICAgICAgICBp bnQgYWxsb2Nfc2l6ZTsKPgo+ICAgICAgICAgaWYgKCFsZHQpCj4gICAgICAgICAgICAgICAgIHJl dHVybjsKPgo+ICAgICAgICAgYWxsb2Nfc2l6ZSA9IHNpemVvZihzdHJ1Y3QgbGR0X3N0cnVjdCkg KyBsZHQtPnNpemUgKiBMRFRfRU5UUllfU0laRTsKPgoKSGFowrggd2UgYm90aCBtaXNzZWQgaXQu ICBUaGlzIGlzIHdyb25nLiAgKEZpeCB5b3VyIGJhY2twb3J0ISkKCj4gICAgICAgICAuLi4KPgo+ PiArICAgICAgICAgICAgIHBhcmF2aXJ0X2ZyZWVfbGR0KGxkdC0+ZW50cmllcywgbGR0LT5zaXpl KTsKPj4gKyAgICAgICAgICAgICBpZiAoYWxsb2Nfc2l6ZSA+IFBBR0VfU0laRSkKPj4gKyAgICAg ICAgICAgICAgICAgICAgIHZmcmVlKGxkdC0+ZW50cmllcyk7Cj4+ICsgICAgICAgICAgICAgZWxz ZQo+PiArICAgICAgICAgICAgICAgICAgICAgcHV0X3BhZ2UodmlydF90b19wYWdlKGxkdC0+ZW50 cmllcykpOwoKSSdtIG5vdCBzdXJlIHRoaXMgaXMgY29ycmVjdCwgc28gSSBjaGFuZ2VkIGl0IHRv IHNvbWV0aGluZyBvYnZpb3VzbHkKY29ycmVjdCAoa21hbGxvYy9rZnJlZSkuCgo+Pgo+PiAtICAg ICBmaWxsX2xkdCgmbGR0LCAmbGR0X2luZm8pOwo+PiAtICAgICBpZiAob2xkbW9kZSkKPj4gLSAg ICAgICAgICAgICBsZHQuYXZsID0gMDsKPj4gKyAgICAgaWYgKG9sZF9sZHQpIHsKPj4gKyAgICAg ICAgICAgICBtZW1jcHkobmV3X2xkdC0+ZW50cmllcywgb2xkX2xkdC0+ZW50cmllcywKPj4gKyAg ICAgICAgICAgICAgICAgICAgb2xkc2l6ZSAqIExEVF9FTlRSWV9TSVpFKTsKPj4gKyAgICAgfQo+ Cj4gU2luZ2xlIGlmLXN0YXRlbWVudCBkb2Vzbid0IG5lZWQge30gYW5kIHlvdSBkb24ndCBhYnNv bHV0ZWx5IG5lZWQgdG8KPiBrZWVwIDgwY29scy4gSnVzdCBsZXQgaXQgc3RpY2sgb3V0LgoKWW91 IHJlYWQgdG9vIG1hbnkgb2YgTGludXMnIGNvbW1lbnRzIGFib3V0IHVzaW5nIHdpZGVyIHRlcm1p bmFscyA6KQoKLS1BbmR5CgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fXwpYZW4tZGV2ZWwgbWFpbGluZyBsaXN0Clhlbi1kZXZlbEBsaXN0cy54ZW4ub3JnCmh0 dHA6Ly9saXN0cy54ZW4ub3JnL3hlbi1kZXZlbAo=