From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Huang Subject: Re: [PATCH][RFC] FPU LWP 3/5: define new FPU interface functions: fpu_save, fpu_restore, fpu_reload Date: Fri, 15 Apr 2011 10:50:48 -0500 Message-ID: <4DA86958.2090901@amd.com> References: <4DA75B57.404@amd.com> <4DA827D9020000780003C9BF@vpn.id2.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4DA827D9020000780003C9BF@vpn.id2.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Will fix. -Wei On 04/15/2011 04:11 AM, Jan Beulich wrote: >>>> On 14.04.11 at 22:38, Wei Huang wrote: >> Current Xen implementation only support lazy FPU reload via CR0.TS. But >> new FPU state isn't always tracked by CR0.TS bit. One example is AMD's >> lightweight profiling. With this patch, Xen calls fpu_save() on vcpu >> which is being scheduled out and fpu_restore() on vcpu which is being >> scheduled in. The nonlazy FPU state is saved and restored in these two >> functions. > This doesn't match the actual patch - only fpu_restore() is being > added to the context switch path, fpu_save() was there already, > saving both lazy and non-lazy state. > >> This patch also defines fpu_reload() to handle lazy FPU state when #NM >> is triggered. >> >> Signed-off-by: Wei Huang >> ... >> +/* Restore VCPU's FPU state when the vcpu is scheduled out */ >> +void fpu_restore(struct vcpu *v) > The comment ought so say "in" rather than "out". > > Jan > >