From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9D4CFCA1016 for ; Mon, 8 Sep 2025 14:33:07 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uvctX-000280-27; Mon, 08 Sep 2025 10:30:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uvctS-00026l-E1 for qemu-devel@nongnu.org; Mon, 08 Sep 2025 10:30:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uvctC-0002Wv-Hc for qemu-devel@nongnu.org; Mon, 08 Sep 2025 10:30:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757341827; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=llpvceQl/WeQu9WHN+bpq9FjG/NNmjKhW6KVEYxrIsI=; b=Eo0Jh14FcF+JCFsRyi+rkGpSuLdGhr9NQ8Z6CkTLtVuA8F6UDr8iWAbNGNP6d20ccjZK2S KdoeoRXT4BIA61v0KJsck93Bp2Hm+YiCBmQpwt59XCaj3tQzTsQScmvyCk/2rbmkBPc+Ag L/o/iwlNOhSuolWszim04UKERZr8Fdk= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-497-5qhixWmwO2KPrn9sthQZwQ-1; Mon, 08 Sep 2025 10:30:26 -0400 X-MC-Unique: 5qhixWmwO2KPrn9sthQZwQ-1 X-Mimecast-MFC-AGG-ID: 5qhixWmwO2KPrn9sthQZwQ_1757341825 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 57CBD1800366 for ; Mon, 8 Sep 2025 14:30:25 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.93]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D4DF01800446; Mon, 8 Sep 2025 14:30:22 +0000 (UTC) Date: Mon, 8 Sep 2025 15:30:19 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Paolo Bonzini Cc: qemu-devel@nongnu.org, Igor Mammedov , Peter Xu Subject: Re: [PULL 24/28] hpet: switch to fine-grained device locking Message-ID: References: <20250829125935.1526984-1-pbonzini@redhat.com> <20250829125935.1526984-25-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250829125935.1526984-25-pbonzini@redhat.com> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, T_SPF_TEMPERROR=0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi, This patches causes a regression making QEMU abort in the KVM Xen functional test. To reproduce please run 'make check-functional-x86_64', or more specifically run this single test: QEMU_TEST_QEMU_BINARY=./build/qemu-system-x86_64 PYTHONPATH=./python:./tests/functional ./tests/functional/x86_64/test_kvm_xen.py though I recommend you first add this series: https://lists.nongnu.org/archive/html/qemu-devel/2025-09/msg01540.html as that fixes an infinite loop in the functional test console code on QEMU abnormal premature exit. In the test logs we see the following on the serial console: 2025-09-08 15:26:32,286: Cannot get hvm parameter CONSOLE_EVTCHN (18): -22! and then the following on stder: qemu-system-x86_64: ../hw/i386/kvm/xen_evtchn.c:1619: xen_evtchn_set_gsi: Assertion `bql_locked()' failed. The QEMU command line was: 2025-09-08 15:26:32,097 - DEBUG: VM launch command: './build/qemu-system-x86_64 -display none -vga none -chardev socket,id=mon,fd=5 -mon chardev=mon,mode=control -chardev socket,id=console,fd=10 -serial chardev:console -accel kvm,xen-version=0x4000a,kernel-irqchip=split -smp 2 -kernel /var/home/berrange/.cache/qemu/download/ec0ad7bb8c33c5982baee0a75505fe7dbf29d3ff5d44258204d6307c6fe0132a -append "printk.time=0 root=/dev/xvda console=ttyS0 quiet xen_emul_unplug=ide-disks" -drive file=/var/home/berrange/.cache/qemu/download/b11045d649006c649c184e93339aaa41a8fe20a1a86620af70323252eb29e40b,if=none,snapshot=on,format=raw,id=drv0 -device xen-disk,drive=drv0,vdev=xvda -device virtio-net-pci,netdev=unet -netdev user,id=unet,hostfwd=:127.0.0.1:0-:22' On Fri, Aug 29, 2025 at 02:59:31PM +0200, Paolo Bonzini wrote: > From: Igor Mammedov > > as a step towards lock-less HPET counter read, > use per device locking instead of BQL. > > Signed-off-by: Igor Mammedov > Reviewed-by: Peter Xu > Link: https://lore.kernel.org/r/20250814160600.2327672-4-imammedo@redhat.com > Signed-off-by: Paolo Bonzini > --- > hw/timer/hpet.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c > index cb48cc151f1..ab5aa59ae4e 100644 > --- a/hw/timer/hpet.c > +++ b/hw/timer/hpet.c > @@ -38,6 +38,7 @@ > #include "hw/timer/i8254.h" > #include "system/address-spaces.h" > #include "qom/object.h" > +#include "qemu/lockable.h" > #include "trace.h" > > struct hpet_fw_config hpet_fw_cfg = {.count = UINT8_MAX}; > @@ -69,6 +70,7 @@ struct HPETState { > SysBusDevice parent_obj; > /*< public >*/ > > + QemuMutex lock; > MemoryRegion iomem; > uint64_t hpet_offset; > bool hpet_offset_saved; > @@ -428,6 +430,7 @@ static uint64_t hpet_ram_read(void *opaque, hwaddr addr, > trace_hpet_ram_read(addr); > addr &= ~4; > > + QEMU_LOCK_GUARD(&s->lock); > /*address range of all global regs*/ > if (addr <= 0xff) { > switch (addr) { > @@ -482,6 +485,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr, > int len = MIN(size * 8, 64 - shift); > uint64_t old_val, new_val, cleared; > > + QEMU_LOCK_GUARD(&s->lock); > trace_hpet_ram_write(addr, value); > addr &= ~4; > > @@ -679,8 +683,10 @@ static void hpet_init(Object *obj) > SysBusDevice *sbd = SYS_BUS_DEVICE(obj); > HPETState *s = HPET(obj); > > + qemu_mutex_init(&s->lock); > /* HPET Area */ > memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", HPET_LEN); > + memory_region_enable_lockless_io(&s->iomem); > sysbus_init_mmio(sbd, &s->iomem); > } > > -- > 2.51.0 > > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|