From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:42652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RWlYm-0000tu-Q5 for qemu-devel@nongnu.org; Sat, 03 Dec 2011 04:07:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RWlYl-0000dr-9U for qemu-devel@nongnu.org; Sat, 03 Dec 2011 04:07:04 -0500 Received: from fmmailgate05.web.de ([217.72.192.243]:57304) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RWlYk-0000dj-UT for qemu-devel@nongnu.org; Sat, 03 Dec 2011 04:07:03 -0500 Received: from moweb001.kundenserver.de (moweb001.kundenserver.de [172.19.20.114]) by fmmailgate05.web.de (Postfix) with ESMTP id 03BAF67B594E for ; Sat, 3 Dec 2011 10:07:02 +0100 (CET) Message-ID: <4ED9E6B0.2000903@web.de> Date: Sat, 03 Dec 2011 10:06:56 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <1322853560-24152-1-git-send-email-emunson@mgebm.net> <4ED9331B.9060708@web.de> <20111202212726.GA5662@mgebm.net> In-Reply-To: <20111202212726.GA5662@mgebm.net> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig704DC3F7DB88BBA0707D2006" Subject: Re: [Qemu-devel] [PATCH V3] Guest stop notification List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric B Munson Cc: "ryanh@linux.vnet.ibm.com" , "aliguori@us.ibm.com" , "kvm@vger.kernel.org" , Marcelo Tosatti , "qemu-devel@nongnu.org" , Avi Kivity This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig704DC3F7DB88BBA0707D2006 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2011-12-02 22:27, Eric B Munson wrote: > On Fri, 02 Dec 2011, Jan Kiszka wrote: >=20 >> On 2011-12-02 20:19, Eric B Munson wrote: >>> Often when a guest is stopped from the qemu console, it will report s= purious >>> soft lockup warnings on resume. There are kernel patches being discu= ssed that >>> will give the host the ability to tell the guest that it is being sto= pped and >>> should ignore the soft lockup warning that generates. >>> >>> Signed-off-by: Eric B Munson >>> Cc: Avi Kivity >>> Cc: Marcelo Tosatti >>> Cc: Jan Kiszka >>> Cc: ryanh@linux.vnet.ibm.com >>> Cc: aliguori@us.ibm.com >>> Cc: kvm@vger.kernel.org >>> >>> --- >>> Changes from V2: >>> Move ioctl into hw/kvmclock.c so as other arches can use it as it is= >>> implemented >>> >>> Changes from V1: >>> Remove unnecessary encapsulating function >>> >>> hw/kvmclock.c | 24 ++++++++++++++++++++++++ >>> 1 files changed, 24 insertions(+), 0 deletions(-) >>> >>> diff --git a/hw/kvmclock.c b/hw/kvmclock.c >>> index 5388bc4..756839f 100644 >>> --- a/hw/kvmclock.c >>> +++ b/hw/kvmclock.c >>> @@ -16,6 +16,7 @@ >>> #include "sysbus.h" >>> #include "kvm.h" >>> #include "kvmclock.h" >>> +#include "cpu-all.h" >>> =20 >>> #include >>> #include >>> @@ -69,11 +70,34 @@ static void kvmclock_vm_state_change(void *opaque= , int running, >>> } >>> } >>> =20 >>> +static void kvmclock_vm_state_change_vcpu(void *opaque, int running,= >>> + RunState state) >>> +{ >>> + int ret; >>> + CPUState *penv =3D first_cpu; >>> + >>> + if (running) { >>> + while (penv) { >> >> or: for (cpu =3D first_cpu; cpu !=3D NULL; cpu =3D cpu->next_cpu) { >> >=20 > Functionally equivalent and I see both in the code, is there a standard= ? Not really. I once tried to introduce an iterator macro, but it was refused. The above is just more compact. But this is only a minor nit. >=20 >>> + ret =3D kvm_vcpu_ioctl(penv, KVM_GUEST_PAUSED, 0); >>> + if (ret) { >>> + if (ret !=3D ENOSYS) { >>> + fprintf(stderr, >>> + "kvmclock_vm_state_change_vcpu: %s\n", >>> + strerror(-ret)); >>> + } >>> + return; >>> + } >>> + penv =3D (CPUState *)penv->next_cpu; >> >> Unneeded cast. >> >=20 > Also following an example seen elsewhere. Generally, we try to avoid those pointless casts. >=20 >>> + } >>> + } >>> +} >>> + >> >> Again: please use checkpatch.pl. >> >=20 > Sorry, tough to get used to hitting space bar that many times... >=20 >>> static int kvmclock_init(SysBusDevice *dev) >>> { >>> KVMClockState *s =3D FROM_SYSBUS(KVMClockState, dev); >>> =20 >>> qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s); >>> + qemu_add_vm_change_state_handler(kvmclock_vm_state_change_vcpu, = NULL); >>> return 0; >>> } >>> =20 >> >> Why not extend the existing handler? >=20 > Because the new handler doesn't touch the KVMClockState object. If thi= s is > preferred, I have no objection. The separate registration looks strange to me. And the fact that you don't need to object doesn't justify a callback of its own. >=20 >> >> I still wonder if the IOCTL interface is actually kvmclock specific. B= ut >> Marcello asked for this, and we could still change it when some arch >> comes around that provides it independent of kvmclock. >=20 > The flag itself is stored in the pvclock_vcpu_time_info structure, and = anything > else that touches that structure uses ioctls. That's the host-guest interface. But I'm talking about the kvm-qemu interface here which has no relation to how the "was paused" information is transferred to the guest. Jan --------------enig704DC3F7DB88BBA0707D2006 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/ iEUEARECAAYFAk7Z5rAACgkQitSsb3rl5xRvZQCgut4Cu996cG6YY8RmmHws8XqY 46MAmOHj/Q+g+/KJec27GFZRT2pmRUg= =Zow7 -----END PGP SIGNATURE----- --------------enig704DC3F7DB88BBA0707D2006--