From nobody Fri Nov 7 15:32:26 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1548684131415918.3961436745143; Mon, 28 Jan 2019 06:02:11 -0800 (PST) Received: from localhost ([127.0.0.1]:60683 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1go7U9-0002fC-Ok for importer@patchew.org; Mon, 28 Jan 2019 09:02:01 -0500 Received: from eggs.gnu.org ([209.51.188.92]:37129) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1go7T2-0002J3-Pb for qemu-devel@nongnu.org; Mon, 28 Jan 2019 09:00:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1go7T1-0007E7-BT for qemu-devel@nongnu.org; Mon, 28 Jan 2019 09:00:52 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45110) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1go7T0-0007DE-Bg for qemu-devel@nongnu.org; Mon, 28 Jan 2019 09:00:50 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id EAE6D2579; Mon, 28 Jan 2019 14:00:48 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-116.ams2.redhat.com [10.36.116.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id C15DF10E1B4A; Mon, 28 Jan 2019 14:00:28 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id C147EA1E8; Mon, 28 Jan 2019 15:00:27 +0100 (CET) From: Gerd Hoffmann To: qemu-devel@nongnu.org Date: Mon, 28 Jan 2019 15:00:27 +0100 Message-Id: <20190128140027.9448-1-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 28 Jan 2019 14:00:49 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] Introduce new "no_guest_reset" parameter for usb-host device X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: agk@godking.net, Gerd Hoffmann Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Alexander Kappner With certain USB devices passed through via usb-host, a guest attempting to reset a usb-host device can trigger a reset loop that renders the USB device unusable. In my use case, the device was an iPhone XR that was passed throu= gh to a Mac OS X Mojave guest. Upon connecting the device, the following happens: 1) Guest recognizes new device, sends reset to emulated USB host 2) QEMU's USB host sends reset to host kernel 3) Host kernel resets device 4) After reset, host kernel determines that some part of the device descrip= tor has changed ("device firmware changed" in dmesg), so host kernel decides to re-enumerate the device. 5) Re-enumeration causes QEMU to disconnect and reconnect the device in the guest. 6) goto 1) Here's from the host kernel (note the "device firmware changed" lines") [3677704.473050] usb 1-1.3: new high-speed USB device number 53 using ehci-= pci [3677704.555594] usb 1-1.3: New USB device found, idVendor=3D05ac, idProduc= t=3D12a8, bcdDevice=3D11.08 [3677704.555599] usb 1-1.3: New USB device strings: Mfr=3D1, Product=3D2, S= erialNumber=3D3 [3677704.555602] usb 1-1.3: Product: iPhone [3677704.555605] usb 1-1.3: Manufacturer: Apple Inc. [3677704.555607] usb 1-1.3: SerialNumber: [[removed]] [3677709.401040] usb 1-1.3: reset high-speed USB device number 53 using ehc= i-pci [3677709.479486] usb 1-1.3: device firmware changed [3677709.479842] usb 1-1.3: USB disconnect, device number 53 [3677709.546039] usb 1-1.3: new high-speed USB device number 54 using ehci-= pci [3677709.627471] usb 1-1.3: New USB device found, idVendor=3D05ac, idProduc= t=3D12a8, bcdDevice=3D11.08 [3677709.627476] usb 1-1.3: New USB device strings: Mfr=3D1, Product=3D2, S= erialNumber=3D3 [3677709.627479] usb 1-1.3: Product: iPhone [3677709.627481] usb 1-1.3: Manufacturer: Apple Inc. [3677709.627483] usb 1-1.3: SerialNumber: [[removed]] [3677762.320044] usb 1-1.3: reset high-speed USB device number 54 using ehc= i-pci [3677762.615630] usb 1-1.3: USB disconnect, device number 54 [3677762.787043] usb 1-1.3: new high-speed USB device number 55 using ehci-= pci [3677762.869016] usb 1-1.3: New USB device found, idVendor=3D05ac, idProduc= t=3D12a8, bcdDevice=3D11.08 [3677762.869024] usb 1-1.3: New USB device strings: Mfr=3D1, Product=3D2, S= erialNumber=3D3 [3677762.869028] usb 1-1.3: Product: iPhone [3677762.869032] usb 1-1.3: Manufacturer: Apple Inc. [3677762.869035] usb 1-1.3: SerialNumber: [[removed]] [3677815.662036] usb 1-1.3: reset high-speed USB device number 55 using ehc= i-pci Here's from QEMU: libusb: error [_get_usbfs_fd] libusb couldn't open USB device /dev/bus/usb/= 005/022: No such file or directory libusb: error [udev_hotplug_event] ignoring udev action bind libusb: error [udev_hotplug_event] ignoring udev action bind libusb: error [_open_sysfs_attr] open /sys/bus/usb/devices/5-1/bConfigurati= onValue failed ret=3D-1 errno=3D2 libusb: error [_get_usbfs_fd] File doesn't exist, wait 10 ms and try again libusb: error [_get_usbfs_fd] libusb couldn't open USB device /dev/bus/usb/= 005/024: No such file or directory libusb: error [udev_hotplug_event] ignoring udev action bind libusb: error [udev_hotplug_event] ignoring udev action bind libusb: error [_open_sysfs_attr] open /sys/bus/usb/devices/5-1/bConfigurati= onValue failed ret=3D-1 errno=3D2 libusb: error [_get_usbfs_fd] File doesn't exist, wait 10 ms and try again libusb: error [_get_usbfs_fd] libusb couldn't open USB device /dev/bus/usb/= 005/026: No such file or directory The result of this is that the device remains permanently unusable in the g= uest. The same problem has been previously reported for an iPad: https://stackoverflow.com/questions/52617634/how-do-i-get-qemu-usb-passthro= ugh-to-work-for-ipad-iphone This problem can be elegantly solved by interrupting step 2) above. Instead= of passing through the reset, QEMU simply ignores it. To allow this to be configured on a per-device level, a new parameter "no_guest_reset" is introduced for the usb-host device. I can confirm that the configuration described above (iPhone XS + Mojave guest) works flawlessly with no_guest_reset=3DTrue specified. Working command line for my scenario: device_add usb-host,vendorid=3D0x05ac,productid=3D0x12a8,no_guest_reset=3DT= rue,id=3Diphone Best regards Alexander Signed-off-by: Alexander Kappner [ kraxel: rename parameter to "guest-reset" ] Signed-off-by: Gerd Hoffmann --- hw/usb/host-libusb.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c index 833250a886..67b7465915 100644 --- a/hw/usb/host-libusb.c +++ b/hw/usb/host-libusb.c @@ -82,7 +82,7 @@ struct USBHostDevice { uint32_t options; uint32_t loglevel; bool needs_autoscan; - + bool allow_guest_reset; /* state */ QTAILQ_ENTRY(USBHostDevice) next; int seen, errcount; @@ -1456,6 +1456,10 @@ static void usb_host_handle_reset(USBDevice *udev) USBHostDevice *s =3D USB_HOST_DEVICE(udev); int rc; =20 + if (!s->allow_guest_reset) { + return; + } + trace_usb_host_reset(s->bus_num, s->addr); =20 rc =3D libusb_reset_device(s->dh); @@ -1573,6 +1577,7 @@ static Property usb_host_dev_properties[] =3D { DEFINE_PROP_UINT32("productid", USBHostDevice, match.product_id, 0), DEFINE_PROP_UINT32("isobufs", USBHostDevice, iso_urb_count, 4), DEFINE_PROP_UINT32("isobsize", USBHostDevice, iso_urb_frames, 32), + DEFINE_PROP_BOOL("guest-reset", USBHostDevice, allow_guest_reset, true= ), DEFINE_PROP_UINT32("loglevel", USBHostDevice, loglevel, LIBUSB_LOG_LEVEL_WARNING), DEFINE_PROP_BIT("pipeline", USBHostDevice, options, --=20 2.9.3