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 30D9ECAC589 for ; Tue, 9 Sep 2025 08:00:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uvtGI-00042Q-Dz; Tue, 09 Sep 2025 03:59:34 -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 1uvtGG-00041D-ES for qemu-devel@nongnu.org; Tue, 09 Sep 2025 03:59:32 -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 1uvtG9-0006Is-0Q for qemu-devel@nongnu.org; Tue, 09 Sep 2025 03:59:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757404761; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=M5lWeCLA1J2GmJuiA7T99O8l4Jz5wOIuEJfofxrsrX4=; b=S7CdxMisBZvqiMoM3+sV+0i4Tkt3UwouUVfsAeZYmgHZVQbMMzQcOvruxBMI5PiSuzZcEp lvV1UgXenqvoRMU8it/hfwv/7hBwgF7rbGldYpZHPasrZvCG6shrmMCdr1d+1GLwpj92fz qhhDWvFH0J0UdwM4M5gE5qGd/7ICmz0= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-651-TEg8Jc2PNQSmvm86S9MI8g-1; Tue, 09 Sep 2025 03:59:19 -0400 X-MC-Unique: TEg8Jc2PNQSmvm86S9MI8g-1 X-Mimecast-MFC-AGG-ID: TEg8Jc2PNQSmvm86S9MI8g_1757404759 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-3e1260394dcso2724411f8f.0 for ; Tue, 09 Sep 2025 00:59:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757404758; x=1758009558; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=M5lWeCLA1J2GmJuiA7T99O8l4Jz5wOIuEJfofxrsrX4=; b=vc/pTY+dwz4EmoZzmShXOv5BKX3baKm3EBNsmLjG3ba69U1HqWzUm6kEzVmrTEul0N dOAWxL1ZDiTa9akXWm4Hh9xm0A069oMPi796MB1/jIlFPE7UT9ViYaNU0GXphLG0OVkn UM8XM92xWqq23DGUjCWLLZl9/vb2mLM1V7aReDApdwzeAyn/RGxoaQLf/UHR2nYWC8q0 ATOChKELR/raF0bfuAFqNNdH8rqhhppxizPokViqCRPY3f0ErtI08g6nTWHoPVieIozW rwzQ6jB63Fpit9zbBeCh2rALu5LsUeT8/PVOPdxqiu9PXOHV2LZXL93AeuIr7/UzbdiO n3JQ== X-Forwarded-Encrypted: i=1; AJvYcCXs9j92AQRQAxGcMEfu39AWOQnCrn4RIPwsZyZaz7uN47fnN6AptMUsM93j/BG1o2BraTcak7q7s5cg@nongnu.org X-Gm-Message-State: AOJu0YxiwA/lm1rIZ+UNzr1ko5FWCDLrsehQrVl6EH+1yZCMoWqbjkMo 6mk3dq1NHqtr+zCeaxGTP+QODXjp3aSWNRnj3UhxRPRhY16op+IouedbRcKYKQvHczYocr6ElVo EdL8zwIH5dSgab/eAwh9vop1QjiIL58ht0Umg7mRJkVpnjh8HPsxD6IF/ X-Gm-Gg: ASbGnctLJMiCvWcvauC32UJ6U8VImE/DdEbI9pwd820zQiIyiIkKTckJahqBkhy+kIA wfBWhJgGakcul/hGiy9tzQ2WdOHlAxx6mszy/mVFHk9y7qaKN5m+ybwqzLAHeIQXSC+V+H9bta8 AfqzkDmZEXQr96B9KAjrY7YOOP87tyw+Gjvk+bqrxVoVWrl/wEZy17EGlgIQ3jteggHFjj2WKAg 6+h7whC7U5eFiHVSplZ2LVeVpU7rGXhQh5tBk7AgDmoaclX7ho1XHZuBkzObFIDRXeoGN+dve0L aN+MNBAcBh3kfm/msLH6KtU0Z/GvBpzdIjqlCPlBifABSIenIebk8xyQ0RKk6Hx6JynTFwh7gZU VBXc= X-Received: by 2002:a05:6000:290e:b0:3e7:516d:9a7c with SMTP id ffacd0b85a97d-3e7516d9d7dmr1112308f8f.39.1757404758525; Tue, 09 Sep 2025 00:59:18 -0700 (PDT) X-Google-Smtp-Source: AGHT+IE6E/5DH/aobdxLbbgf74svV6tuol+GZ0kZiVXeJWiedrdpUav/n/fa59tAlVZ3zu2SSrpQ7g== X-Received: by 2002:a05:6000:290e:b0:3e7:516d:9a7c with SMTP id ffacd0b85a97d-3e7516d9d7dmr1112287f8f.39.1757404758037; Tue, 09 Sep 2025 00:59:18 -0700 (PDT) Received: from ?IPV6:2a01:e0a:280:24f0:576b:abc6:6396:ed4a? ([2a01:e0a:280:24f0:576b:abc6:6396:ed4a]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3e7521bfe00sm1598797f8f.5.2025.09.09.00.59.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Sep 2025 00:59:17 -0700 (PDT) Message-ID: Date: Tue, 9 Sep 2025 09:59:16 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/4] s390x/pci: Add PCI error handling for vfio pci devices To: Matthew Rosato , Farhan Ali , qemu-devel@nongnu.org, qemu-s390x@nongnu.org Cc: thuth@redhat.com, alex.williamson@redhat.com References: <20250825212434.2255-1-alifm@linux.ibm.com> <20250825212434.2255-4-alifm@linux.ibm.com> <24333a79-2a49-4abb-8bb7-8e5b30a0d58b@redhat.com> <5ed9c5ef-cb1d-428c-a822-9f378fabd755@linux.ibm.com> From: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= Content-Language: en-US, fr Autocrypt: addr=clg@redhat.com; keydata= xsFNBFu8o3UBEADP+oJVJaWm5vzZa/iLgpBAuzxSmNYhURZH+guITvSySk30YWfLYGBWQgeo 8NzNXBY3cH7JX3/a0jzmhDc0U61qFxVgrPqs1PQOjp7yRSFuDAnjtRqNvWkvlnRWLFq4+U5t yzYe4SFMjFb6Oc0xkQmaK2flmiJNnnxPttYwKBPd98WfXMmjwAv7QfwW+OL3VlTPADgzkcqj 53bfZ4VblAQrq6Ctbtu7JuUGAxSIL3XqeQlAwwLTfFGrmpY7MroE7n9Rl+hy/kuIrb/TO8n0 ZxYXvvhT7OmRKvbYuc5Jze6o7op/bJHlufY+AquYQ4dPxjPPVUT/DLiUYJ3oVBWFYNbzfOrV RxEwNuRbycttMiZWxgflsQoHF06q/2l4ttS3zsV4TDZudMq0TbCH/uJFPFsbHUN91qwwaN/+ gy1j7o6aWMz+Ib3O9dK2M/j/O/Ube95mdCqN4N/uSnDlca3YDEWrV9jO1mUS/ndOkjxa34ia 70FjwiSQAsyIwqbRO3CGmiOJqDa9qNvd2TJgAaS2WCw/TlBALjVQ7AyoPEoBPj31K74Wc4GS Rm+FSch32ei61yFu6ACdZ12i5Edt+To+hkElzjt6db/UgRUeKfzlMB7PodK7o8NBD8outJGS tsL2GRX24QvvBuusJdMiLGpNz3uqyqwzC5w0Fd34E6G94806fwARAQABzSJDw6lkcmljIExl IEdvYXRlciA8Y2xnQHJlZGhhdC5jb20+wsGRBBMBCAA7FiEEoPZlSPBIlev+awtgUaNDx8/7 7KEFAmTLlVECGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgkQUaNDx8/77KG0eg// S0zIzTcxkrwJ/9XgdcvVTnXLVF9V4/tZPfB7sCp8rpDCEseU6O0TkOVFoGWM39sEMiQBSvyY lHrP7p7E/JYQNNLh441MfaX8RJ5Ul3btluLapm8oHp/vbHKV2IhLcpNCfAqaQKdfk8yazYhh EdxTBlzxPcu+78uE5fF4wusmtutK0JG0sAgq0mHFZX7qKG6LIbdLdaQalZ8CCFMKUhLptW71 xe+aNrn7hScBoOj2kTDRgf9CE7svmjGToJzUxgeh9mIkxAxTu7XU+8lmL28j2L5uNuDOq9vl hM30OT+pfHmyPLtLK8+GXfFDxjea5hZLF+2yolE/ATQFt9AmOmXC+YayrcO2ZvdnKExZS1o8 VUKpZgRnkwMUUReaF/mTauRQGLuS4lDcI4DrARPyLGNbvYlpmJWnGRWCDguQ/LBPpbG7djoy k3NlvoeA757c4DgCzggViqLm0Bae320qEc6z9o0X0ePqSU2f7vcuWN49Uhox5kM5L86DzjEQ RHXndoJkeL8LmHx8DM+kx4aZt0zVfCHwmKTkSTQoAQakLpLte7tWXIio9ZKhUGPv/eHxXEoS 0rOOAZ6np1U/xNR82QbF9qr9TrTVI3GtVe7Vxmff+qoSAxJiZQCo5kt0YlWwti2fFI4xvkOi V7lyhOA3+/3oRKpZYQ86Frlo61HU3r6d9wzOwU0EW7yjdQEQALyDNNMw/08/fsyWEWjfqVhW pOOrX2h+z4q0lOHkjxi/FRIRLfXeZjFfNQNLSoL8j1y2rQOs1j1g+NV3K5hrZYYcMs0xhmrZ KXAHjjDx7FW3sG3jcGjFW5Xk4olTrZwFsZVUcP8XZlArLmkAX3UyrrXEWPSBJCXxDIW1hzwp bV/nVbo/K9XBptT/wPd+RPiOTIIRptjypGY+S23HYBDND3mtfTz/uY0Jytaio9GETj+fFis6 TxFjjbZNUxKpwftu/4RimZ7qL+uM1rG1lLWc9SPtFxRQ8uLvLOUFB1AqHixBcx7LIXSKZEFU CSLB2AE4wXQkJbApye48qnZ09zc929df5gU6hjgqV9Gk1rIfHxvTsYltA1jWalySEScmr0iS YBZjw8Nbd7SxeomAxzBv2l1Fk8fPzR7M616dtb3Z3HLjyvwAwxtfGD7VnvINPbzyibbe9c6g LxYCr23c2Ry0UfFXh6UKD83d5ybqnXrEJ5n/t1+TLGCYGzF2erVYGkQrReJe8Mld3iGVldB7 JhuAU1+d88NS3aBpNF6TbGXqlXGF6Yua6n1cOY2Yb4lO/mDKgjXd3aviqlwVlodC8AwI0Sdu jWryzL5/AGEU2sIDQCHuv1QgzmKwhE58d475KdVX/3Vt5I9kTXpvEpfW18TjlFkdHGESM/Jx IqVsqvhAJkalABEBAAHCwV8EGAECAAkFAlu8o3UCGwwACgkQUaNDx8/77KEhwg//WqVopd5k 8hQb9VVdk6RQOCTfo6wHhEqgjbXQGlaxKHoXywEQBi8eULbeMQf5l4+tHJWBxswQ93IHBQjK yKyNr4FXseUI5O20XVNYDJZUrhA4yn0e/Af0IX25d94HXQ5sMTWr1qlSK6Zu79lbH3R57w9j hQm9emQEp785ui3A5U2Lqp6nWYWXz0eUZ0Tad2zC71Gg9VazU9MXyWn749s0nXbVLcLS0yop s302Gf3ZmtgfXTX/W+M25hiVRRKCH88yr6it+OMJBUndQVAA/fE9hYom6t/zqA248j0QAV/p LHH3hSirE1mv+7jpQnhMvatrwUpeXrOiEw1nHzWCqOJUZ4SY+HmGFW0YirWV2mYKoaGO2YBU wYF7O9TI3GEEgRMBIRT98fHa0NPwtlTktVISl73LpgVscdW8yg9Gc82oe8FzU1uHjU8b10lU XOMHpqDDEV9//r4ZhkKZ9C4O+YZcTFu+mvAY3GlqivBNkmYsHYSlFsbxc37E1HpTEaSWsGfA HQoPn9qrDJgsgcbBVc1gkUT6hnxShKPp4PlsZVMNjvPAnr5TEBgHkk54HQRhhwcYv1T2QumQ izDiU6iOrUzBThaMhZO3i927SG2DwWDVzZltKrCMD1aMPvb3NU8FOYRhNmIFR3fcalYr+9gD uVKe8BVz4atMOoktmt0GWTOC8P4= In-Reply-To: <5ed9c5ef-cb1d-428c-a822-9f378fabd755@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=clg@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, SPF_PASS=-0.001 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 9/3/25 19:49, Matthew Rosato wrote: > On 9/3/25 1:12 PM, Farhan Ali wrote: >> >> On 9/1/2025 4:25 AM, Cédric Le Goater wrote: >>> On 8/25/25 23:24, Farhan Ali wrote: >>>> Add an s390x specific callback for vfio error handling. For s390x pci devices, >>>> we have platform specific error information. We need to retrieve this error >>>> information for passthrough devices. This is done via a memory region which >>>> exposes that information. >>>> >>>> Once this error information is retrieved we can then inject an error into >>>> the guest, and let the guest drive the recovery. >>>> >>>> Signed-off-by: Farhan Ali >>>> --- >>>>   hw/s390x/s390-pci-bus.c          |  5 +++ >>>>   hw/s390x/s390-pci-vfio.c         | 76 ++++++++++++++++++++++++++++++++ >>>>   include/hw/s390x/s390-pci-bus.h  |  1 + >>>>   include/hw/s390x/s390-pci-vfio.h |  2 + >>>>   4 files changed, 84 insertions(+) >>>> >>>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c >>>> index f87d2748b6..af42eb9938 100644 >>>> --- a/hw/s390x/s390-pci-bus.c >>>> +++ b/hw/s390x/s390-pci-bus.c >>>> @@ -158,6 +158,8 @@ static void s390_pci_perform_unplug(S390PCIBusDevice *pbdev) >>>>   { >>>>       HotplugHandler *hotplug_ctrl; >>>>   +    qemu_mutex_destroy(&pbdev->err_handler_lock); >>>> + >>>>       if (pbdev->pft == ZPCI_PFT_ISM) { >>>>           notifier_remove(&pbdev->shutdown_notifier); >>>>       } >>>> @@ -1140,6 +1142,7 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev, >>>>           pbdev->iommu->pbdev = pbdev; >>>>           pbdev->state = ZPCI_FS_DISABLED; >>>>           set_pbdev_info(pbdev); >>>> +        qemu_mutex_init(&pbdev->err_handler_lock); >>>>             if (object_dynamic_cast(OBJECT(dev), "vfio-pci")) { >>>>               /* >>>> @@ -1164,6 +1167,8 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev, >>>>               pbdev->iommu->dma_limit = s390_pci_start_dma_count(s, pbdev); >>>>               /* Fill in CLP information passed via the vfio region */ >>>>               s390_pci_get_clp_info(pbdev); >>>> +            /* Setup error handler for error recovery */ >>>> +            s390_pci_setup_err_handler(pbdev); >>> >>> This can fail. Please add an 'Error **' parameter and change the returned >>> value to bool. >>> >> I wanted to avoid hard failing here as we can have mismatch in kernel and QEMU support for the feature. For example we can have a newer QEMU version with the feature running on an older kernel. So wanted to treat any error in setting up the error handler would be more of an info/warn message. > > +1, please do not cause a hard failure if the underlying host kernel is simply missing support... It doesn't have to be a hard failure. The code could issue a warn_report_err(). Similarly to what is done for the vfio_ap device when IRQ notifying support is not available on the host. This is minor. C. > >>>> +void s390_pci_setup_err_handler(S390PCIBusDevice *pbdev) >>>> +{ >>>> +    int ret; >>>> +    VFIOPCIDevice *vfio_pci =  container_of(pbdev->pdev, VFIOPCIDevice, pdev); >>>> +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature), >>>> +                              sizeof(uint64_t))] = {}; >>>> +    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf; >>>> + >>>> +    feature->argsz = sizeof(buf); >>>> +    feature->flags = VFIO_DEVICE_FEATURE_PROBE | VFIO_DEVICE_FEATURE_ZPCI_ERROR; >>>> + >>>> +    ret = vfio_pci->vbasedev.io_ops->device_feature(&vfio_pci->vbasedev, >>>> +                                                     feature); >>> >>> Please introduce vfio helpers to hide the internal indirection : >>> >>>   ->vbasedev.io_ops->device_feature(...) >>> >>>> + >>>> +    if (ret) { >>> >>> Shouldn't we test the return value to decide if the error is >>> an unimplemented feature or an unexpected error ? >> >> Yeah, I think it makes sense separate out error for unimplemented feature (ENOTTY) vs any other unexpected error. Will change this. >> > > ... But if you add differentiation here between the 2 types of errors then I would be fine with hard-fail for unexpected cases and info/warn for missing host kernel support.