From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Date: Thu, 03 Jul 2014 12:28:58 +0000 Subject: Re: [PATCH 3/6 v2] KVM: PPC: Book3E: Increase FPU laziness Message-Id: <53B54C8A.1060209@suse.de> List-Id: References: <1404142497-6430-1-git-send-email-mihai.caraman@freescale.com> <1404142497-6430-4-git-send-email-mihai.caraman@freescale.com> In-Reply-To: <1404142497-6430-4-git-send-email-mihai.caraman@freescale.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Mihai Caraman , kvm-ppc@vger.kernel.org Cc: kvm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org On 30.06.14 17:34, Mihai Caraman wrote: > Increase FPU laziness by calling kvmppc_load_guest_fp() just before > returning to guest instead of each sched in. Without this improvement > an interrupt may also claim floting point corrupting guest state. How do you handle context switching with this patch applied? During most of the guest's lifetime we never exit kvmppc_vcpu_run(), so when the guest gets switched out all FPU state gets lost? Alex From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) (using TLSv1 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 164DE1A0004 for ; Thu, 3 Jul 2014 22:29:02 +1000 (EST) Message-ID: <53B54C8A.1060209@suse.de> Date: Thu, 03 Jul 2014 14:28:58 +0200 From: Alexander Graf MIME-Version: 1.0 To: Mihai Caraman , kvm-ppc@vger.kernel.org Subject: Re: [PATCH 3/6 v2] KVM: PPC: Book3E: Increase FPU laziness References: <1404142497-6430-1-git-send-email-mihai.caraman@freescale.com> <1404142497-6430-4-git-send-email-mihai.caraman@freescale.com> In-Reply-To: <1404142497-6430-4-git-send-email-mihai.caraman@freescale.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 30.06.14 17:34, Mihai Caraman wrote: > Increase FPU laziness by calling kvmppc_load_guest_fp() just before > returning to guest instead of each sched in. Without this improvement > an interrupt may also claim floting point corrupting guest state. How do you handle context switching with this patch applied? During most of the guest's lifetime we never exit kvmppc_vcpu_run(), so when the guest gets switched out all FPU state gets lost? Alex From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH 3/6 v2] KVM: PPC: Book3E: Increase FPU laziness Date: Thu, 03 Jul 2014 14:28:58 +0200 Message-ID: <53B54C8A.1060209@suse.de> References: <1404142497-6430-1-git-send-email-mihai.caraman@freescale.com> <1404142497-6430-4-git-send-email-mihai.caraman@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org To: Mihai Caraman , kvm-ppc@vger.kernel.org Return-path: In-Reply-To: <1404142497-6430-4-git-send-email-mihai.caraman@freescale.com> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 30.06.14 17:34, Mihai Caraman wrote: > Increase FPU laziness by calling kvmppc_load_guest_fp() just before > returning to guest instead of each sched in. Without this improvement > an interrupt may also claim floting point corrupting guest state. How do you handle context switching with this patch applied? During most of the guest's lifetime we never exit kvmppc_vcpu_run(), so when the guest gets switched out all FPU state gets lost? Alex