From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Kardashevskiy Date: Thu, 11 Jul 2013 12:56:17 +0000 Subject: Re: [PATCH 6/8] KVM: PPC: Add support for multiple-TCE hcalls Message-Id: <51DEAB71.8020109@ozlabs.ru> List-Id: References: <1373123227-22969-1-git-send-email-aik@ozlabs.ru> <1373123227-22969-7-git-send-email-aik@ozlabs.ru> <51DC4228.7010607@suse.de> <51DCEA76.9070808@ozlabs.ru> <51DE3ECB.7080803@ozlabs.ru> <43E93931-F213-47CC-ADCF-D3A6D6BC4372@suse.de> <51DE8EE9.2000508@ozlabs.ru> <1373546368.19894.87.camel@pasglop> <4133424D-B105-4CB1-A72A-4F47A6184DC7@suse.de> In-Reply-To: <4133424D-B105-4CB1-A72A-4F47A6184DC7@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Alexander Graf Cc: Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, David Gibson , Paul Mackerras , Alex Williamson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org On 07/11/2013 10:51 PM, Alexander Graf wrote: > > On 11.07.2013, at 14:39, Benjamin Herrenschmidt wrote: > >> On Thu, 2013-07-11 at 13:15 +0200, Alexander Graf wrote: >>> And that's bad. Jeez, seriously. Don't argue this case. We enable new >>> features individually unless we're 100% sure we can keep everything >>> working. In this case an ENABLE_CAP doesn't hurt at all, because user >>> space still needs to handle the hypercalls if it wants them anyways. >>> But you get debugging for free for example. >> >> An ENABLE_CAP is utterly pointless. More bloat. But you seem to like >> it :-) > > I don't like bloat usually. But Alexey even had an #ifdef DEBUG in there > to selectively disable in-kernel handling of multi-TCE. Not calling > ENABLE_CAP would give him exactly that without ugly #ifdefs in the > kernel. No, it would not give m anithing. My ugly debug was to disable realmode only and still leave virtual mode on, not to disable both real and virtual modes. It is a lot easier to disable in kernel handling in QEMU. -- Alexey From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f43.google.com (mail-pa0-f43.google.com [209.85.220.43]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (not verified)) by ozlabs.org (Postfix) with ESMTPS id D47522C0308 for ; Thu, 11 Jul 2013 22:56:28 +1000 (EST) Received: by mail-pa0-f43.google.com with SMTP id hz11so7828270pad.16 for ; Thu, 11 Jul 2013 05:56:25 -0700 (PDT) Message-ID: <51DEAB71.8020109@ozlabs.ru> Date: Thu, 11 Jul 2013 22:56:17 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 To: Alexander Graf Subject: Re: [PATCH 6/8] KVM: PPC: Add support for multiple-TCE hcalls References: <1373123227-22969-1-git-send-email-aik@ozlabs.ru> <1373123227-22969-7-git-send-email-aik@ozlabs.ru> <51DC4228.7010607@suse.de> <51DCEA76.9070808@ozlabs.ru> <51DE3ECB.7080803@ozlabs.ru> <43E93931-F213-47CC-ADCF-D3A6D6BC4372@suse.de> <51DE8EE9.2000508@ozlabs.ru> <1373546368.19894.87.camel@pasglop> <4133424D-B105-4CB1-A72A-4F47A6184DC7@suse.de> In-Reply-To: <4133424D-B105-4CB1-A72A-4F47A6184DC7@suse.de> Content-Type: text/plain; charset=KOI8-R Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, Alex Williamson , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, David Gibson List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 07/11/2013 10:51 PM, Alexander Graf wrote: > > On 11.07.2013, at 14:39, Benjamin Herrenschmidt wrote: > >> On Thu, 2013-07-11 at 13:15 +0200, Alexander Graf wrote: >>> And that's bad. Jeez, seriously. Don't argue this case. We enable new >>> features individually unless we're 100% sure we can keep everything >>> working. In this case an ENABLE_CAP doesn't hurt at all, because user >>> space still needs to handle the hypercalls if it wants them anyways. >>> But you get debugging for free for example. >> >> An ENABLE_CAP is utterly pointless. More bloat. But you seem to like >> it :-) > > I don't like bloat usually. But Alexey even had an #ifdef DEBUG in there > to selectively disable in-kernel handling of multi-TCE. Not calling > ENABLE_CAP would give him exactly that without ugly #ifdefs in the > kernel. No, it would not give m anithing. My ugly debug was to disable realmode only and still leave virtual mode on, not to disable both real and virtual modes. It is a lot easier to disable in kernel handling in QEMU. -- Alexey From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Kardashevskiy Subject: Re: [PATCH 6/8] KVM: PPC: Add support for multiple-TCE hcalls Date: Thu, 11 Jul 2013 22:56:17 +1000 Message-ID: <51DEAB71.8020109@ozlabs.ru> References: <1373123227-22969-1-git-send-email-aik@ozlabs.ru> <1373123227-22969-7-git-send-email-aik@ozlabs.ru> <51DC4228.7010607@suse.de> <51DCEA76.9070808@ozlabs.ru> <51DE3ECB.7080803@ozlabs.ru> <43E93931-F213-47CC-ADCF-D3A6D6BC4372@suse.de> <51DE8EE9.2000508@ozlabs.ru> <1373546368.19894.87.camel@pasglop> <4133424D-B105-4CB1-A72A-4F47A6184DC7@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Cc: Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, David Gibson , Paul Mackerras , Alex Williamson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org To: Alexander Graf Return-path: In-Reply-To: <4133424D-B105-4CB1-A72A-4F47A6184DC7@suse.de> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 07/11/2013 10:51 PM, Alexander Graf wrote: > > On 11.07.2013, at 14:39, Benjamin Herrenschmidt wrote: > >> On Thu, 2013-07-11 at 13:15 +0200, Alexander Graf wrote: >>> And that's bad. Jeez, seriously. Don't argue this case. We enable new >>> features individually unless we're 100% sure we can keep everything >>> working. In this case an ENABLE_CAP doesn't hurt at all, because user >>> space still needs to handle the hypercalls if it wants them anyways. >>> But you get debugging for free for example. >> >> An ENABLE_CAP is utterly pointless. More bloat. But you seem to like >> it :-) > > I don't like bloat usually. But Alexey even had an #ifdef DEBUG in there > to selectively disable in-kernel handling of multi-TCE. Not calling > ENABLE_CAP would give him exactly that without ugly #ifdefs in the > kernel. No, it would not give m anithing. My ugly debug was to disable realmode only and still leave virtual mode on, not to disable both real and virtual modes. It is a lot easier to disable in kernel handling in QEMU. -- Alexey