From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=53893 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1POBFb-0002Sw-0m for qemu-devel@nongnu.org; Thu, 02 Dec 2010 10:39:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1POBFO-0006AN-E9 for qemu-devel@nongnu.org; Thu, 02 Dec 2010 10:39:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24347) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1POBFO-00069w-5z for qemu-devel@nongnu.org; Thu, 02 Dec 2010 10:39:02 -0500 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id oB2Fd08H019556 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 2 Dec 2010 10:39:01 -0500 Date: Thu, 2 Dec 2010 17:38:43 +0200 From: "Michael S. Tsirkin" Subject: Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate Message-ID: <20101202153843.GB4313@redhat.com> References: <20101129153718.GA2494@redhat.com> <19701.57573.766694.450729@gargle.gargle.HOWL> <20101201060252.GB9199@redhat.com> <19703.38782.929586.869640@gargle.gargle.HOWL> <20101202130823.GD2454@redhat.com> <19703.43787.213477.834653@gargle.gargle.HOWL> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19703.43787.213477.834653@gargle.gargle.HOWL> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: mtosatti@redhat.com, qemu-devel@nongnu.org, quintela@redhat.com On Thu, Dec 02, 2010 at 10:19:55PM +0800, Jason Wang wrote: > Michael S. Tsirkin writes: > > On Thu, Dec 02, 2010 at 08:56:30PM +0800, Jason Wang wrote: > > > Michael S. Tsirkin writes: > > > > On Wed, Dec 01, 2010 at 01:45:09PM +0800, Jason Wang wrote: > > > > > Michael S. Tsirkin writes: > > > > > > Avoid sending out packets, and modifying > > > > > > device state, when VM is stopped. > > > > > > Add assert statements to verify this does not happen. > > > > > > > > > > > > Avoid scheduling bh when vhost-net is started. > > > > > > > > > > > > Stop bh when driver disabled bus mastering > > > > > > (we must not access memory after this). > > > > > > > > > > > > Signed-off-by: Michael S. Tsirkin > > > > > > > > > > > > > > > > There's no need to disable it bh we call qemu_aio_flush() after > > > > > vm_state_notify() in do_vm_stop(). And for timer, looks like every device should > > > > > stop its timer in vm state change handler, not only for virtio-net? > > > > > > > > BTW I fixed some typos. Here a fixed version. > > > > Jason, could you review/test please? > > > > > > > > > > Have done the test, it's more stable than before but still get small deltas in > > > cpu section. > > > > And just to clarify: no more deltas in the memory section? > > > > Yes. > > And the offset for cpu section is 1161-1165 As far as I can say the state is in target-i386/machine.c static const VMStateDescription vmstate_cpu. Need to do some math to find this: I think this is mtrr_var, but maybe my math is off. I would sugest printing out the state and see what is changed exactly. > and sometimes I get deltas for ide > section at offset 295 and 314. I see that ide has some bh processing. Most likely that starts io after vmstop? I suggest adding a vm state handler and checking vm status in ide_dma_restart_bh. Start with an assert, just for debug. Also, what if we use virtio-blk? > > > I didn't find any interesting difference by checking the > > > CPUX86State in the dest in kvm_arch_load_regs(), any thought on this? > > > > > > BTW, looks like the error_code was missed in saving the cpu state: > > > > > > diff --git a/target-i386/cpu.h b/target-i386/cpu.h > > > index 35a1a51..145bb38 100644 > > > --- a/target-i386/cpu.h > > > +++ b/target-i386/cpu.h > > > @@ -687,7 +687,7 @@ typedef struct CPUX86State { > > > uint64_t pat; > > > > > > /* exception/interrupt handling */ > > > - int error_code; > > > + uint32_t error_code; > > > int exception_is_int; > > > target_ulong exception_next_eip; > > > target_ulong dr[8]; /* debug registers */ > > > @@ -935,7 +935,7 @@ CPUState *pc_new_cpu(const char *cpu_model); > > > #define cpu_list_id x86_cpu_list > > > #define cpudef_setup x86_cpudef_setup > > > > > > -#define CPU_SAVE_VERSION 12 > > > +#define CPU_SAVE_VERSION 13 > > > > > > /* MMU modes definitions */ > > > #define MMU_MODE0_SUFFIX _kernel > > > diff --git a/target-i386/machine.c b/target-i386/machine.c > > > index 4398801..fa231d8 100644 > > > --- a/target-i386/machine.c > > > +++ b/target-i386/machine.c > > > @@ -474,6 +474,8 @@ static const VMStateDescription vmstate_cpu = { > > > VMSTATE_UINT64_V(xcr0, CPUState, 12), > > > VMSTATE_UINT64_V(xstate_bv, CPUState, 12), > > > VMSTATE_YMMH_REGS_VARS(ymmh_regs, CPUState, CPU_NB_REGS, 12), > > > + > > > + VMSTATE_UINT32_V(error_code, CPUState, 13), > > > VMSTATE_END_OF_LIST() > > > /* The above list is not sorted /wrt version numbers, watch out! */ > > > }