From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Martin Subject: Re: [Query] Flow of PCI device dedicated to a domU Date: Tue, 22 Jul 2014 17:01:54 +0100 Message-ID: <1346394447.20140722170154@gmail.com> References: <53C64AF8.90001@citrix.com> <53CE3541.80506@citrix.com> <53CE3DE2.8060908@citrix.com> <1721487090.20140722165657@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1721487090.20140722165657@gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Simon Martin Cc: Andrew Cooper , Xenbegn developer , xen-devel@lists.xen.org, ian.campbell@citrix.com, Stefano Stabellini List-Id: xen-devel@lists.xenproject.org Hello Simon, Tuesday, July 22, 2014, 4:56:57 PM, you wrote: > Hello Stefano, >> The basic mechanism is that Xen assigns the PCI root complex/host >> bridge to Dom0. Dom0 walks the bus and finds out the devices available. >> When the user assigns a PCI device to a VM, the toolstack (xl/libxl) >> issues hypercalls to remap interrupts and MMIO regions of that device >> into the guest VM. > I am currently trying writing my own PCI front to access directly a > PCI device from my PV guest. > If I read this correctly you are saying that the MMIO region is > already mapped into my domain by xl? So when I go and read the BAR > register from the PCI configuration I can just go and access it > directly or do I have to update the VA mapping? Just a clarification here, when I say "go and access it" what I meant to say was "go and access directly in my PV the memory at the BAR address". -- Best regards, Simon mailto:furryfuttock@gmail.com