{"id":2231352,"url":"http://patchwork.ozlabs.org/api/patches/2231352/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260430160307.634093-11-cohuck@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260430160307.634093-11-cohuck@redhat.com>","list_archive_url":null,"date":"2026-04-30T16:03:06","name":"[PULL,v2,10/11] hw/s390x/ccw: Disable legacy virtio-pci by default (v11.1+)","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"6ee68f1f65e64dd76b8a3450c9ed9d8eac1e7da0","submitter":{"id":71914,"url":"http://patchwork.ozlabs.org/api/people/71914/?format=json","name":"Cornelia Huck","email":"cohuck@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260430160307.634093-11-cohuck@redhat.com/mbox/","series":[{"id":502335,"url":"http://patchwork.ozlabs.org/api/series/502335/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=502335","date":"2026-04-30T16:02:58","name":"[PULL,v2,01/11] target/s390x/kvm: Simplify the async pfault handling code","version":2,"mbox":"http://patchwork.ozlabs.org/series/502335/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2231352/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2231352/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=Pp62dvrp;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1777565021;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:content-type:content-type:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=MYssZ2jX6kV2gh+5VY85dXxJGS2UBMoRMWXKR4lB6jo=;\n b=Pp62dvrpfYByZxPuu80Lm1nSR0Cox/lo3WVAhM33xMFlGclnoE1I1uRueY/bMskx4oLJ0k\n +qY305kwYolCG8fAHng76nI33pZSjNppcKSaGXXh0m6OQytptECCwKid5WhLIl82vQSLnW\n O3l8CVSx8PsyHuNJr4t1mRub15dANC8=","X-MC-Unique":"_MP2ON3jPWOWjxPI6_imyw-1","X-Mimecast-MFC-AGG-ID":"_MP2ON3jPWOWjxPI6_imyw_1777565016","From":"Cornelia Huck ","To":"qemu-devel@nongnu.org","Cc":"qemu-s390x@nongnu.org, Jaehoon Kim ,\n Mohamed Mediouni ,\n Halil Pasic , Matthew Rosato ,\n Cornelia Huck ","Subject":"[PULL v2 10/11] hw/s390x/ccw: Disable legacy virtio-pci by default\n (v11.1+)","Date":"Thu, 30 Apr 2026 18:03:06 +0200","Message-ID":"<20260430160307.634093-11-cohuck@redhat.com>","In-Reply-To":"<20260430160307.634093-1-cohuck@redhat.com>","References":"<20260430160307.634093-1-cohuck@redhat.com>","MIME-Version":"1.0","Content-type":"text/plain","Content-Transfer-Encoding":"8bit","X-Scanned-By":"MIMEDefang 3.4.1 on 10.30.177.111","Received-SPF":"pass client-ip=170.10.133.124; envelope-from=cohuck@redhat.com;\n 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,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001,\n SPF_HELO_PASS=-0.001,\n SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"From: Jaehoon Kim \n\nOn the s390 Linux kernel, IO_SPACE_LIMIT has been 0 since the initial\nzPCI implementation (commit cd24834130ac \"s390/pci: base support\"),\nmaking I/O BARs unusable.\n\nHowever, when virtio-pci devices operate in transitional mode, QEMU\nunconditionally exposes the legacy interface via BAR0. This results in\nfirmware warnings during PCI enumeration, such as:\n\n pci 0005:00:00.0: [Firmware Bug]: BAR 0: invalid; can't size\n\neven though BAR0 is never usable on the s390 kernel.\n\nClose this gap by disabling legacy virtio-pci support starting from\nmachine version 11.1. This effectively makes virtio-pci devices\nnon-transitional and prevents the creation of the unusable legacy I/O\nBAR.\n\nThis introduces s390x-specific global compatibility properties that\nset disable-legacy=on as the default for virtio-pci devices. Machine\nversions v11.0 and earlier set disable-legacy=off to maintain their\noriginal default behavior (legacy support enabled), ensuring VMs\ncreated with those versions continue to work identically.\n\nUsers can override the default on the command line if needed:\n - On v11.1+: -global virtio-pci.disable-legacy=off (to enable legacy)\n - On v11.0-: -global virtio-pci.disable-legacy=on (to disable legacy)\n\nSigned-off-by: Jaehoon Kim \nReviewed-by: Mohamed Mediouni \nReviewed-by: Halil Pasic \nReviewed-by: Matthew Rosato \nTested-by: Matthew Rosato \nMessage-ID: <20260420144759.2970726-2-jhkim@linux.ibm.com>\nSigned-off-by: Cornelia Huck \n---\n hw/s390x/s390-virtio-ccw.c | 26 ++++++++++++++++++++++++++\n 1 file changed, 26 insertions(+)","diff":"diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c\nindex cc768daeb04c..4d35f9b10bcc 100644\n--- a/hw/s390x/s390-virtio-ccw.c\n+++ b/hw/s390x/s390-virtio-ccw.c\n@@ -788,6 +788,21 @@ static void machine_set_loadparm(Object *obj, Visitor *v,\n g_free(val);\n }\n \n+ /*\n+ * S390x-specific global compatibility properties.\n+ *\n+ * On the s390 kernel, legacy virtio-pci is not usable because I/O BARs\n+ * are not supported (IO_SPACE_LIMIT is 0), and would only result in\n+ * unusable BARs and firmware warnings.\n+ *\n+ * Therefore, starting from v11.1, disable legacy virtio-pci by default,\n+ * while older machine types keep legacy behavior for compatibility.\n+ */\n+static GlobalProperty hw_compat_s390x[] = {\n+ { TYPE_VIRTIO_PCI, \"disable-legacy\", \"on\", .optional = true},\n+};\n+static const size_t hw_compat_s390x_len = G_N_ELEMENTS(hw_compat_s390x);\n+\n static void ccw_machine_class_init(ObjectClass *oc, const void *data)\n {\n MachineClass *mc = MACHINE_CLASS(oc);\n@@ -878,6 +893,9 @@ static const TypeInfo ccw_machine_info = {\n const void *data) \\\n { \\\n MachineClass *mc = MACHINE_CLASS(oc); \\\n+ /* Apply global s390x-wide default properties */ \\\n+ compat_props_add(mc->compat_props, hw_compat_s390x, \\\n+ hw_compat_s390x_len); \\\n MACHINE_VER_SYM(class_options, ccw, __VA_ARGS__)(mc); \\\n mc->desc = \"Virtual s390x machine (version \" MACHINE_VER_STR(__VA_ARGS__) \")\"; \\\n mc->init = MACHINE_VER_SYM(mach_init, ccw, __VA_ARGS__); \\\n@@ -923,7 +941,15 @@ static void ccw_machine_11_0_instance_options(MachineState *machine)\n \n static void ccw_machine_11_0_class_options(MachineClass *mc)\n {\n+ /*\n+ * Preserve v11.0 and older version behavior:\n+ * keep legacy virtio-pci enabled.\n+ */\n+ static GlobalProperty compat[] = {\n+ { TYPE_VIRTIO_PCI, \"disable-legacy\", \"off\" },\n+ };\n ccw_machine_11_1_class_options(mc);\n+ compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));\n compat_props_add(mc->compat_props, hw_compat_11_0, hw_compat_11_0_len);\n }\n DEFINE_CCW_MACHINE(11, 0);\n","prefixes":["PULL","v2","10/11"]}