From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH v3 1/5] hpet 'driftfix': add hooks required to detect coalesced interrupts (x86 apic only) Date: Fri, 29 Apr 2011 12:15:27 +0200 Message-ID: <4DBA8FBF.1020505@siemens.com> References: <722267231.277846.1304070351482.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: aliguori@us.ibm.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, gcosta@redhat.com, Blue Swirl , avi@redhat.com To: Ulrich Obergfell Return-path: In-Reply-To: <722267231.277846.1304070351482.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org On 2011-04-29 11:45, Ulrich Obergfell wrote: > >> On 2011-04-28 20:51, Blue Swirl wrote: >>> On Thu, Apr 28, 2011 at 5:24 PM, Ulrich Obergfell wrote: >>>> 'target_get_irq_delivered' and 'target_reset_irq_delivered' contain >>>> entry addresses of functions that are utilized by update_irq() to >>>> detect coalesced interrupts. apic code loads these pointers during >>>> initialization. >>> >>> I'm not so happy with this approach, but probably then the i386 >>> dependencies can be removed from RTC and it can be compiled only once >>> for all targets. >> >> This whole series is really the minimalistic approach. The callbacks >> defined here must remain a temporary "shortcut". Just like proper >> abstraction of periodic tick compensation for reuse in other timers has >> to be added later on. And the limitation to edge-triggered legacy HPET >> INTs has to be removed. > > Since QEMU doesn't have a generic infrastructure to track interrupt > delivery, I decided to reuse something that is currently available. > The only mechanism that I'm aware of is the one that is utilized by > RTC code ('rtc_td_hack'), i.e. apic_get_irq_delivered() etc. > > The changes that would be introduced by part 1/5 and part 4/5 of > this patch series could be replaced if a generic infrastructure > to track interrupt delivery becomes available. Right, and I hope you have the resources to continue working on this topic in the foreseeable future. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux