From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [Android-virt] [PATCH v5 05/13] ARM: KVM: Inject IRQs and FIQs from userspace Date: Mon, 12 Dec 2011 00:01:55 +0100 Message-ID: <4EE53663.2050808@web.de> References: <20111211102403.21693.6887.stgit@localhost> <20111211102449.21693.12265.stgit@localhost> <4EE4C9D8.1010601@web.de> <-4744042178058961854@unknownmsgid> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig5B9AC80CEC892770EEAE5FE7" Cc: Peter Maydell , "kvm@vger.kernel.org" , "Marc.Zyngier@arm.com" , "avi@redhat.com" , "android-virt@lists.cs.columbia.edu" , "tech@virtualopensystems.com" To: Christoffer Dall Return-path: Received: from fmmailgate02.web.de ([217.72.192.227]:58719 "EHLO fmmailgate02.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752330Ab1LKXCP (ORCPT ); Sun, 11 Dec 2011 18:02:15 -0500 Received: from moweb001.kundenserver.de (moweb001.kundenserver.de [172.19.20.114]) by fmmailgate02.web.de (Postfix) with ESMTP id 6B3501BB37052 for ; Mon, 12 Dec 2011 00:02:14 +0100 (CET) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig5B9AC80CEC892770EEAE5FE7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2011-12-11 23:53, Christoffer Dall wrote: > On Sun, Dec 11, 2011 at 5:35 PM, Peter Maydell wrote: >> On 11 December 2011 22:12, Peter Maydell wr= ote: >>> (Actually what would be clearest would be if the ioctl took the >>> (interrupt-target, interrupt-line-for-that-target, value-of-line) >>> tuple as three separate values rather than encoding two of them into >>> a single integer, but I assume there's a reason we can't have that.) >> >> Have you thought about how this encoding scheme would be extended >> when we move to using the VGIC and an in-kernel interrupt controller >> implementation, incidentally? I haven't really looked into that at >> all, but I assume that then QEMU is going to start having to tell >> the kernel it wants to deliver interrupt 35 to the GIC, and so on... >> >> > no, I haven't looked into that at all. My plan was to decipher the > common irq, ioapic stuff for x86 and see how much we can re-use and if > there will be some nice way to either use what's there or change some > bits to accomodate both existing archs and ARM. But the short answer > is, no not really, I was focusing so far on getting a stable > implementation upstream. >=20 > yes, we are going to have to have some interface with QEMU for this > and if we need new features from what's already there that should > probably be discussed in the same round as the mechanism for handing > of CP15 stuff to QEMU that we touched upon earlier. Enabling in-kernel irqchips usually means "switching worlds". So the semantics of these particular IRQ inject interface details may change without breaking anything. However, things might look different if there will be a need to inject also the CPU IRQs directly, not only the irqchip inputs. In that case, it may make some sense to reserve more space for interrupt types than just one bit and use a common encoding scheme. Jan --------------enig5B9AC80CEC892770EEAE5FE7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk7lNmgACgkQitSsb3rl5xQStgCgjO1toZBa5AEpUUqYfXbhvZix RYUAn3cu3tUsg3tiI3fYdDgWN71dVGCc =vYFj -----END PGP SIGNATURE----- --------------enig5B9AC80CEC892770EEAE5FE7--