From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:46444) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QzoF1-000846-Ns for qemu-devel@nongnu.org; Sat, 03 Sep 2011 07:18:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QzoF0-0005zr-JW for qemu-devel@nongnu.org; Sat, 03 Sep 2011 07:18:27 -0400 Received: from fmmailgate03.web.de ([217.72.192.234]:45688) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QzoF0-0005zh-8m for qemu-devel@nongnu.org; Sat, 03 Sep 2011 07:18:26 -0400 Message-ID: <4E620CD4.7040205@web.de> Date: Sat, 03 Sep 2011 13:17:40 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <4E58FC3F.6080809@web.de> <4E5F4B81.2050905@siemens.com> In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig68192EAEC94274F3DF0FC1F7" Sender: jan.kiszka@web.de Subject: Re: [Qemu-devel] [PATCH v2] pc: Fix and clean up PIC-to-APIC IRQ path List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Blue Swirl Cc: Lucas Meneghel Rodrigues , Anthony Liguori , Marcelo Tosatti , qemu-devel , Avi Kivity , Gerd Hoffmann This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig68192EAEC94274F3DF0FC1F7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 2011-09-03 10:58, Blue Swirl wrote: > On Thu, Sep 1, 2011 at 9:08 AM, Jan Kiszka wro= te: >> The master PIC is connected to the LINTIN0 of the APICs. As the APIC >> currently does not track the state of that line, we have to ask the PI= C >> to reinject its IRQ after the CPU picked up an event from the APIC. >> >> This introduces pic_get_output to read the master PIC IRQ line state >> without changing it. The APIC uses this function to decide if a PIC IR= Q >> should be reinjected on apic_update_irq. This reflects better how the >> real hardware works. >> >> The patch fixes some failures of the kvm unit tests apic and eventinj = by >> allowing to enable the proper CPU IRQ deassertion when the guest masks= >> some pending IRQs at PIC level. >> >> Signed-off-by: Jan Kiszka >> --- >> >> Changes in v2: >> - Avoid adding pic_level to the APIC state, obtain PIC output via >> pic_get_level instead >> - Do not reassert PIC interrupt if APIC is not accepting it >> - Use apic_deliver_pic_intr for reassertion to ensure correct >> processing >> >> This is not as nice as the previous version /wrt the interaction of PI= C >> and APIC. But it avoids breaking the APIC vmstate for the sake of >> internal changes, also keeping it compatible with the upcoming KVM >> in-kernel APIC (that allows no easy pic_level state extraction). The >> interconnection between PIC and APIC may look nicer in the future with= >> QOM. And in the end this just reflects the "beauty" of the x86 >> architecture. >> >> hw/apic.c | 4 ++++ >> hw/i8259.c | 15 +++++++-------- >> hw/pc.c | 3 --- >> hw/pc.h | 2 +- >> 4 files changed, 12 insertions(+), 12 deletions(-) >> >> diff --git a/hw/apic.c b/hw/apic.c >> index d8f56c8..8289eef 100644 >> --- a/hw/apic.c >> +++ b/hw/apic.c >> @@ -23,6 +23,7 @@ >> #include "host-utils.h" >> #include "sysbus.h" >> #include "trace.h" >> +#include "pc.h" >> >> /* APIC Local Vector Table */ >> #define APIC_LVT_TIMER 0 >> @@ -399,6 +400,9 @@ static void apic_update_irq(APICState *s) >> } >> if (apic_irq_pending(s) > 0) { >> cpu_interrupt(s->cpu_env, CPU_INTERRUPT_HARD); >> + } else if (apic_accept_pic_intr(&s->busdev.qdev) && >> + pic_get_output(isa_pic)) { >=20 > This is indeed ugly. Why doesn't APIC track PIC output? For the reasons explained above. Jan --------------enig68192EAEC94274F3DF0FC1F7 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/ iEYEARECAAYFAk5iDNcACgkQitSsb3rl5xS/DgCgwplQlEdpjHcFu8TS1g7lfE3O 7H8AoI1I/rgr/XLdtk+2dLJpLLRzRqrY =JOtr -----END PGP SIGNATURE----- --------------enig68192EAEC94274F3DF0FC1F7--