From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH RFC] Driver to support shared memory with interrupts with broadcast Date: Thu, 30 Jul 2009 23:22:54 +0300 Message-ID: <20090730202254.GA3949@redhat.com> References: <1248972607-8818-1-git-send-email-cam@cs.ualberta.ca> <4A71E6A0.2080601@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Cam Macdonell , kvm@vger.kernel.org To: Anthony Liguori Return-path: Received: from mx2.redhat.com ([66.187.237.31]:33882 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752737AbZG3UYC (ORCPT ); Thu, 30 Jul 2009 16:24:02 -0400 Content-Disposition: inline In-Reply-To: <4A71E6A0.2080601@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Jul 30, 2009 at 01:29:52PM -0500, Anthony Liguori wrote: > Cam Macdonell wrote: >> This driver allows the guest VM to access shared memory between other guest >> that is a POSIX shared memory object on the host. The driver can also send >> interrupts by writing to the DoorBell register. >> >> With interrupts, the ioctl must specify the ID of the VM to receive the >> interrupt or '255' for broadcast to all active VMs. The 'arg' parameter is the >> destination VM and 'cmd' is the interrupt code. The value written to the >> register is a bit messy. 32-bits are written to the register, the upper 16 are >> the destination VM, and the lower 16 are the interrupt 'code' that the >> destination guest will receive. Implemented codes (see the interrupt handler) >> either call up on the device's semaphore or wake up on the wait_event queue. >> These codes' uses are at the discretion of the driver so they could be >> customized. >> >> For ioctls that read values from the device (such as for getting the global ID >> of the guest) the arg parameter is unused. >> >> Cam >> > > I think you should just use Michael's uio_pci driver. I don't think we > have a need for a new kernel interface. If that's what you want to do, an example device that generates interrupts in response to config writes can be found here: http://www.archivum.info/qemu-devel@nongnu.org/2009-07/01548/%5BQemu-devel%5D_%5BPATCH%5D_qemu:_test-irq_device > Regards, > > Anthony Liguori > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html