From mboxrd@z Thu Jan 1 00:00:00 1970 From: "tiejun.chen" Subject: Re: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts Date: Thu, 9 May 2013 15:47:50 +0800 Message-ID: <518B54A6.1070505@windriver.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit 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" To: Bhushan Bharat-R65777 Return-path: In-Reply-To: <6A3DF150A5B70D4F9B66A25E3F7C888D0700E50E@039-SN2MPN1-011.039d.mgd.msft.net> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org 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 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) 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