From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH v15 17/21] x86/VPMU: Handle PMU interrupts for PV guests Date: Wed, 26 Nov 2014 09:39:12 -0500 Message-ID: <5475E610.2020707@oracle.com> References: <1416179271-1221-1-git-send-email-boris.ostrovsky@oracle.com> <1416179271-1221-18-git-send-email-boris.ostrovsky@oracle.com> <5474A028020000780004AB58@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5474A028020000780004AB58@mail.emea.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: kevin.tian@intel.com, keir@xen.org, suravee.suthikulpanit@amd.com, andrew.cooper3@citrix.com, tim@xen.org, dietmar.hahn@ts.fujitsu.com, xen-devel@lists.xen.org, Aravind.Gopalakrishnan@amd.com, jun.nakajima@intel.com, dgdegra@tycho.nsa.gov List-Id: xen-devel@lists.xenproject.org On 11/25/2014 09:28 AM, Jan Beulich wrote: > >> + else >> + { >> + struct segment_register seg; >> + >> + hvm_get_segment_register(sampled, x86_seg_cs, &seg); >> + r->cs = seg.sel; >> + hvm_get_segment_register(sampled, x86_seg_ss, &seg); >> + r->ss = seg.sel; >> + if ( seg.attr.fields.dpl != 0 ) >> + *flags |= PMU_SAMPLE_USER; > Is that how hardware treats it (CPL != 0 meaning user, rather > than CPL == 3)? You mean how *software* (e.g. Linux kernel) treats it? If yes, then for 32-bit user_mode() checks for (CS == 3) and for 64-bit it's !!(CS & 3). > Maybe you should surface CPL instead of a > boolean flag? Am I not already doing it by passing SS and CS to the guest? -boris > > Anyway, with or without the adjustments (unless you go a 3rd > way) > Acked-by: Jan Beulich > > Jan >