From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH 1/3] x86/xen: Avoid fast syscall path for Xen PV guests Date: Wed, 18 Nov 2015 21:47:52 +0100 Message-ID: <20151118204752.GF4451@pd.tnic> References: <1447877179-2775-1-git-send-email-boris.ostrovsky@oracle.com> <1447877179-2775-2-git-send-email-boris.ostrovsky@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Andy Lutomirski Cc: Konrad Rzeszutek Wilk , "linux-kernel@vger.kernel.org" , Linux Virtualization , Ingo Molnar , David Vrabel , Andrew Lutomirski , "H. Peter Anvin" , "xen-devel@lists.xenproject.org" , Boris Ostrovsky , Thomas Gleixner List-Id: virtualization@lists.linuxfoundation.org T24gV2VkLCBOb3YgMTgsIDIwMTUgYXQgMTI6MjE6NTZQTSAtMDgwMCwgQW5keSBMdXRvbWlyc2tp IHdyb3RlOgo+ID4gZGlmZiAtLWdpdCBhL2FyY2gveDg2L2luY2x1ZGUvYXNtL2NwdWZlYXR1cmUu aCBiL2FyY2gveDg2L2luY2x1ZGUvYXNtL2NwdWZlYXR1cmUuaAo+ID4gaW5kZXggZTRmODAxMC4u MGU0ZmU1YiAxMDA2NDQKPiA+IC0tLSBhL2FyY2gveDg2L2luY2x1ZGUvYXNtL2NwdWZlYXR1cmUu aAo+ID4gKysrIGIvYXJjaC94ODYvaW5jbHVkZS9hc20vY3B1ZmVhdHVyZS5oCj4gPiBAQCAtMjE2 LDYgKzIxNiw3IEBACj4gPiAgI2RlZmluZSBYODZfRkVBVFVSRV9QQVVTRUZJTFRFUiAoIDgqMzIr MTMpIC8qIEFNRCBmaWx0ZXJlZCBwYXVzZSBpbnRlcmNlcHQgKi8KPiA+ICAjZGVmaW5lIFg4Nl9G RUFUVVJFX1BGVEhSRVNIT0xEICggOCozMisxNCkgLyogQU1EIHBhdXNlIGZpbHRlciB0aHJlc2hv bGQgKi8KPiA+ICAjZGVmaW5lIFg4Nl9GRUFUVVJFX1ZNTUNBTEwgICAgICggOCozMisxNSkgLyog UHJlZmVyIHZtbWNhbGwgdG8gdm1jYWxsICovCj4gPiArI2RlZmluZSBYODZfRkVBVFVSRV9YRU5Q ViAgICAgICAoIDgqMzIrMTYpIC8qIFhlbiBwYXJhdmlydHVhbCBndWVzdCAqLwo+ID4KPiAKPiBU aGlzIGJpdCBpcyBoaWdobHkgbWFnaWNhbCBhbmQgSSB0aGluayB3ZSBuZWVkIEJvcmlzbGF2J3Mg YWNrLgoKWWVhaCwgdGhhdCBzaG91bGQgYmUKCiNkZWZpbmUgWDg2X0ZFQVRVUkVfWEVOUFYgICAg ICAgKCA4KjMyKzE2KSAvKiAiIiBYZW4gcGFyYXZpcnR1YWwgZ3Vlc3QgKi8KCQkJCQkgICAgICBe XgoKbm90ZSB0aGUgZW1wdHkgIiIuIFRoaXMgcHJldmVudHMgaXQgZnJvbSBhcHBlYXJpbmcgaW4g L3Byb2MvY3B1aW5mby4KCi0tIApSZWdhcmRzL0dydXNzLAogICAgQm9yaXMuCgpTVVNFIExpbnV4 IEdtYkgsIEdGOiBGZWxpeCBJbWVuZMO2cmZmZXIsIEphbmUgU21pdGhhcmQsIEdyYWhhbSBOb3J0 b24sIEhSQiAyMTI4NCAoQUcgTsO8cm5iZXJnKQotLSAKX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX18KVmlydHVhbGl6YXRpb24gbWFpbGluZyBsaXN0ClZpcnR1 YWxpemF0aW9uQGxpc3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhm b3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZvL3ZpcnR1YWxpemF0aW9u From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757020AbbKRUsJ (ORCPT ); Wed, 18 Nov 2015 15:48:09 -0500 Received: from mx2.suse.de ([195.135.220.15]:37437 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756997AbbKRUsG (ORCPT ); Wed, 18 Nov 2015 15:48:06 -0500 Date: Wed, 18 Nov 2015 21:47:52 +0100 From: Borislav Petkov To: Andy Lutomirski Cc: Boris Ostrovsky , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , David Vrabel , Konrad Rzeszutek Wilk , Andrew Lutomirski , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xenproject.org" , Linux Virtualization Subject: Re: [PATCH 1/3] x86/xen: Avoid fast syscall path for Xen PV guests Message-ID: <20151118204752.GF4451@pd.tnic> References: <1447877179-2775-1-git-send-email-boris.ostrovsky@oracle.com> <1447877179-2775-2-git-send-email-boris.ostrovsky@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 18, 2015 at 12:21:56PM -0800, Andy Lutomirski wrote: > > diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h > > index e4f8010..0e4fe5b 100644 > > --- a/arch/x86/include/asm/cpufeature.h > > +++ b/arch/x86/include/asm/cpufeature.h > > @@ -216,6 +216,7 @@ > > #define X86_FEATURE_PAUSEFILTER ( 8*32+13) /* AMD filtered pause intercept */ > > #define X86_FEATURE_PFTHRESHOLD ( 8*32+14) /* AMD pause filter threshold */ > > #define X86_FEATURE_VMMCALL ( 8*32+15) /* Prefer vmmcall to vmcall */ > > +#define X86_FEATURE_XENPV ( 8*32+16) /* Xen paravirtual guest */ > > > > This bit is highly magical and I think we need Borislav's ack. Yeah, that should be #define X86_FEATURE_XENPV ( 8*32+16) /* "" Xen paravirtual guest */ ^^ note the empty "". This prevents it from appearing in /proc/cpuinfo. -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --