From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Subject: Re: HVMlite ABI specification DRAFT A Date: Fri, 5 Feb 2016 12:30:25 +0100 Message-ID: <56B487D1.4080902@citrix.com> References: <56B38EDE.5090700@citrix.com> <56B396ED.7010209@citrix.com> <56B4757A02000078000CEE45@prv-mh.provo.novell.com> <56B47048.8090206@citrix.com> <56B48A1E02000078000CEF6F@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aReav-0001sE-TT for xen-devel@lists.xenproject.org; Fri, 05 Feb 2016 11:30:34 +0000 In-Reply-To: <56B48A1E02000078000CEF6F@prv-mh.provo.novell.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: Jan Beulich Cc: Wei Liu , Stefano Stabellini , Andrew Cooper , Tim Deegan , Paul Durrant , David Vrabel , xen-devel , samuel.thibault@ens-lyon.org, Boris Ostrovsky List-Id: xen-devel@lists.xenproject.org El 5/2/16 a les 11:40, Jan Beulich ha escrit: >>>> On 05.02.16 at 10:50, wrote: >> For legacy PCI interrupts, we can parse the MADT inside of Xen in order >> to properly setup the lines/overwrites and inject the interrupts that >> are not handled by Xen straight into the hardware domain. This will >> require us to be able to emulate the same topology as what is found in >> native (eg: if there are two IO APICs in the hardware we should also >> provide two emulated ones to the hw domain). > > I don't think MADT contains all the needed information, or else we > wouldn't need PHYSDEVOP_setup_gsi. AFAICT, I think we could do something like: - IRQs [0, 15]: edge-trigger, low-polarity. - IRQs [16, n]: level-triggered, high-polarity. Unless there's an overwrite in the MADT. Then there are interrupts that are handled by Xen, which would not be passed-through to the hardware domain, the rest would be. I expect that Xen will already have some code to deal with this, since it's also used for regular PCI-passthrough. >> As for PCI config space accesses, don't we already do that? We trap on >> access to the 0xcf8 io port. > > We intercept that, but iirc we do no translation (and for DomU > these get forwarded to qemu anyway). > >>>>> * `eflags`: bit 17 (VM) must be cleared. Bit 9 (IF) must be cleared. >>>>> Bit 8 (TF) must be cleared. Other bits are all unspecified. >>>> >>>> I would also specify that the direction flag shall be clear, to prevent >>>> all kernels needing to `cld` on entry. >>> >>> In which case IOPL and AC state should perhaps also be nailed down? >>> Possibly even all of the control ones (leaving only the status flags >>> unspecified)? >> >> Status flag? Why don't we just say that all user-settable bits in the >> status register will be set to 0 (or cleared)? > > Would be an option too. AFAICT that's what we already do, so I will add it to the next iteration.