From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.windriver.com (mail.windriver.com [147.11.1.11]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mail.windriver.com", Issuer "Intel External Basic Issuing CA 3A" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 0A4122C00E2 for ; Thu, 9 May 2013 18:05:01 +1000 (EST) Message-ID: <518B58A0.1030100@windriver.com> Date: Thu, 9 May 2013 16:04:48 +0800 From: "tiejun.chen" MIME-Version: 1.0 To: Bhushan Bharat-R65777 Subject: Re: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts References: <51885F49.6060605@windriver.com> (from tiejun.chen@windriver.com on Mon May 6 20:56:25 2013) <1367892390.3398.12@snotra> <300B73AA675FCE4A93EB4FC1D42459FF3F00D0@039-SN2MPN1-013.039d.mgd.msft.net> <6A3DF150A5B70D4F9B66A25E3F7C888D0700E50E@039-SN2MPN1-011.039d.mgd.msft.net> <518B54A6.1070505@windriver.com> <6A3DF150A5B70D4F9B66A25E3F7C888D0700E563@039-SN2MPN1-011.039d.mgd.msft.net> In-Reply-To: <6A3DF150A5B70D4F9B66A25E3F7C888D0700E563@039-SN2MPN1-011.039d.mgd.msft.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Cc: Caraman Mihai Claudiu-B02008 , "kvm@vger.kernel.org" , Wood Scott-B07421 , "agraf@suse.de" , "kvm-ppc@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 05/09/2013 03:51 PM, Bhushan Bharat-R65777 wrote: > > >> -----Original Message----- >> From: tiejun.chen [mailto:tiejun.chen@windriver.com] >> Sent: Thursday, May 09, 2013 1:18 PM >> To: Bhushan Bharat-R65777 >> Cc: Caraman Mihai Claudiu-B02008; Wood Scott-B07421; linuxppc- >> dev@lists.ozlabs.org; agraf@suse.de; kvm-ppc@vger.kernel.org; >> kvm@vger.kernel.org >> Subject: Re: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts >> >> On 05/09/2013 03:33 PM, Bhushan Bharat-R65777 wrote: >>> >>> >>>> -----Original Message----- >>>> From: Linuxppc-dev [mailto:linuxppc-dev- >>>> bounces+bharat.bhushan=freescale.com@lists.ozlabs.org] On Behalf Of >>>> bounces+Caraman >>>> Mihai Claudiu-B02008 >>>> Sent: Wednesday, May 08, 2013 6:44 PM >>>> To: Wood Scott-B07421; tiejun.chen >>>> Cc: linuxppc-dev@lists.ozlabs.org; agraf@suse.de; >>>> kvm-ppc@vger.kernel.org; kvm@vger.kernel.org >>>> Subject: RE: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable >>>> interrupts >>>> >>>>>> This only disable soft interrupt for kvmppc_restart_interrupt() >>>>>> that restarts interrupts if they were meant for the host: >>>>>> >>>>>> a. SOFT_DISABLE_INTS() only for BOOKE_INTERRUPT_EXTERNAL | >>>>>> BOOKE_INTERRUPT_DECREMENTER | BOOKE_INTERRUPT_DOORBELL >>>>> >>>>> Those aren't the only exceptions that can end up going to the host. >>>>> We could get a TLB miss that results in a heavyweight MMIO exit, etc. >>>>> >>>>>> And shouldn't we handle kvmppc_restart_interrupt() like the >>>>>> original HOST flow? >>>>>> >>>>>> #define MASKABLE_EXCEPTION(trapnum, intnum, label, hdlr, >>>>>> ack) \ >>>>>> >>>>>> START_EXCEPTION(label); \ >>>>>> NORMAL_EXCEPTION_PROLOG(trapnum, intnum, >>>>>> PROLOG_ADDITION_MASKABLE)\ >>>>>> EXCEPTION_COMMON(trapnum, PACA_EXGEN, >>>>>> *INTS_DISABLE*) \ >>>>>> ... >>>>> >>>>> Could you elaborate on what you mean? >>>> >>>> I think Tiejun was saying that host has flags and replays only >>>> EE/DEC/DBELL interrupts. There is special macro >>>> masked_interrupt_book3e in those exception handlers that sets paca- >>> irq_happened. >>>> >>>> The list of replied interrupts is limited to asynchronous noncritical >>>> interrupts which can be masked by MSR[EE] (therefore no TLB miss). >>> >>> Embedded Perfmon interrupt is also asynchronous, Why that is not in the list >> of masked interruts. >> >> Are you saying perfmon? If so, its also in that list: >> >> START_EXCEPTION(perfmon); >> NORMAL_EXCEPTION_PROLOG(0x260, BOOKE_INTERRUPT_PERFORMANCE_MONITOR, >> PROLOG_ADDITION_NONE) >> EXCEPTION_COMMON(0x260, PACA_EXGEN, INTS_DISABLE) > > Where it is recorded in paca->irq_happned to be replayed later ? In stead of PROLOG_ADDITION_MASKABLE, actually we have nothing to do with PROLOG_ADDITION_NONE for perfmon, so perfmon can be executed without lazy state. Tiejun > >> >> Tiejun >> >>> >>> -Bharat >>> >>>> Now on KVM book3e we >>>> don't want to put them in the irq_happened lazy state but rather to >>>> execute them directly, so there is no reason for exception handling >>>> symmetry between host and guest. >>>> >>>> -Mike >> >