From nobody Wed Nov 27 18:55:18 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org ARC-Seal: i=1; a=rsa-sha256; t=1697730305; cv=none; d=zohomail.com; s=zohoarc; b=g0C1xXsfk63OxMHR5cLFydu735+EjE5Ciqa44WKqCmrZvZ6sEYfMwkV4oNy72z/qlcB/OO7BgvlOM2GOxw9eJWzcQ2S6mmK2QJBrvqw5eu7mkUb6BRnhiNiirBaf07rJSfNGQoivTCncvwW7bLuHt3Kub0wS+NP3RS4t+/201nE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1697730305; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=MzyeUS8+Q6DyGG1BYkZOM8Vo8wKa2UEntgjHbKC7sqQ=; b=d6vRpedp9l0Dc09W/WeJPNlN1exbN7nutk+4LxF8itAD/NCmYpSOxWiBOnt5IEvVD2D1aEWB75Kriphisa2Pr3dLz8Its45f4GXWfXHYJmKOdyMBADxouSyfRgXVjaDMi0byJMrlWf+XwxGNktXE6DMT6hxnC6WipQWjeGW5tyM= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1697730305283307.4506693059408; Thu, 19 Oct 2023 08:45:05 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.619482.964635 (Exim 4.92) (envelope-from ) id 1qtVCT-0004P8-4z; Thu, 19 Oct 2023 15:44:41 +0000 Received: by outflank-mailman (output) from mailman id 619482.964635; Thu, 19 Oct 2023 15:44:41 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qtVCT-0004OS-0a; Thu, 19 Oct 2023 15:44:41 +0000 Received: by outflank-mailman (input) for mailman id 619482; Thu, 19 Oct 2023 15:44:39 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qtV8y-0006dc-CA for xen-devel@lists.xenproject.org; Thu, 19 Oct 2023 15:41:04 +0000 Received: from desiato.infradead.org (desiato.infradead.org [2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id e77ac9a3-6e95-11ee-9b0e-b553b5be7939; Thu, 19 Oct 2023 17:41:01 +0200 (CEST) Received: from [2001:8b0:10b:1::ebe] (helo=i7.infradead.org) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qtV8O-009yCs-0P; Thu, 19 Oct 2023 15:40:28 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1qtV8M-000PuW-24; Thu, 19 Oct 2023 16:40:26 +0100 X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list X-Inumbo-ID: e77ac9a3-6e95-11ee-9b0e-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=MzyeUS8+Q6DyGG1BYkZOM8Vo8wKa2UEntgjHbKC7sqQ=; b=lZba3Mv1zHO4kaMfOaXiCwtb+O wkslMdOA/sxcZ8z+TsvaxomvGGtAfw1gSBhna7Jmba1Z8fUOvcSarzhanIcn0e789VCRxX7PfZbfJ FB6Vjrn1KH0rWBXo62DIX99QdNvCwAwRMahWDqtC+8HlZeGFUKNRDMUhDDeQUCArM25zXmW3o98Kz 93esbTShMa3BYKGQVUXv0Wlw6wxw91TwPUFTxJh3oQECcSs/18SJbwD5uHupEmtFRjTEwiRLJIfe0 5CwpZMOWYOyJStEA1vn17LINb/uXQXJ1+at1fqvaTGKQ2Irh6EIqN8fbpep94f/Aywl2/mEG+C2sr OOmZoFVQ==; From: David Woodhouse To: qemu-devel@nongnu.org Cc: Kevin Wolf , Hanna Reitz , Stefano Stabellini , Anthony Perard , Paul Durrant , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Paolo Bonzini , Richard Henderson , Eduardo Habkost , "Michael S. Tsirkin" , Marcel Apfelbaum , Jason Wang , Marcelo Tosatti , Cleber Rosa , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Wainer dos Santos Moschetta , Beraldo Leal , qemu-block@nongnu.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org, Bernhard Beschow , Joel Upham Subject: [PATCH v2 13/24] hw/xen: do not repeatedly try to create a failing backend device Date: Thu, 19 Oct 2023 16:40:09 +0100 Message-Id: <20231019154020.99080-14-dwmw2@infradead.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20231019154020.99080-1-dwmw2@infradead.org> References: <20231019154020.99080-1-dwmw2@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by desiato.infradead.org. See http://www.infradead.org/rpr.html X-ZohoMail-DKIM: pass (identity @infradead.org) X-ZM-MESSAGEID: 1697730305999100005 Content-Type: text/plain; charset="utf-8" From: David Woodhouse If xen_backend_device_create() fails to instantiate a device, the XenBus code will just keep trying over and over again each time the bus is re-enumerated, as long as the backend appears online and in XenbusStateInitialising. The only thing which prevents the XenBus code from recreating duplicates of devices which already exist, is the fact that xen_device_realize() sets the backend state to XenbusStateInitWait. If the attempt to create the device doesn't get *that* far, that's when it will keep getting retried. My first thought was to handle errors by setting the backend state to XenbusStateClosed, but that doesn't work for XenConsole which wants to *ignore* any device of type !=3D "ioemu" completely. So, make xen_backend_device_create() *keep* the XenBackendInstance for a failed device, and provide a new xen_backend_exists() function to allow xen_bus_type_enumerate() to check whether one already exists before creating a new one. Signed-off-by: David Woodhouse --- hw/xen/xen-backend.c | 27 +++++++++++++++++++++------ hw/xen/xen-bus.c | 3 ++- include/hw/xen/xen-backend.h | 1 + 3 files changed, 24 insertions(+), 7 deletions(-) diff --git a/hw/xen/xen-backend.c b/hw/xen/xen-backend.c index 5b0fb76eae..b9bf70a9f5 100644 --- a/hw/xen/xen-backend.c +++ b/hw/xen/xen-backend.c @@ -101,6 +101,24 @@ static XenBackendInstance *xen_backend_list_find(XenDe= vice *xendev) return NULL; } =20 +bool xen_backend_exists(const char *type, const char *name) +{ + const XenBackendImpl *impl =3D xen_backend_table_lookup(type); + XenBackendInstance *backend; + + if (!impl) { + return false; + } + + QLIST_FOREACH(backend, &backend_list, entry) { + if (backend->impl =3D=3D impl && !strcmp(backend->name, name)) { + return true; + } + } + + return false; +} + static void xen_backend_list_remove(XenBackendInstance *backend) { QLIST_REMOVE(backend, entry); @@ -122,11 +140,6 @@ void xen_backend_device_create(XenBus *xenbus, const c= har *type, backend->name =3D g_strdup(name); =20 impl->create(backend, opts, errp); - if (*errp) { - g_free(backend->name); - g_free(backend); - return; - } =20 backend->impl =3D impl; xen_backend_list_add(backend); @@ -165,7 +178,9 @@ bool xen_backend_try_device_destroy(XenDevice *xendev, = Error **errp) } =20 impl =3D backend->impl; - impl->destroy(backend, errp); + if (backend->xendev) { + impl->destroy(backend, errp); + } =20 xen_backend_list_remove(backend); g_free(backend->name); diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index cc524ed92c..0da2aa219a 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -209,7 +209,8 @@ static void xen_bus_type_enumerate(XenBus *xenbus, cons= t char *type) NULL, "%u", &online) !=3D 1) online =3D 0; =20 - if (online && state =3D=3D XenbusStateInitialising) { + if (online && state =3D=3D XenbusStateInitialising && + !xen_backend_exists(type, backend[i])) { Error *local_err =3D NULL; =20 xen_bus_backend_create(xenbus, type, backend[i], backend_path, diff --git a/include/hw/xen/xen-backend.h b/include/hw/xen/xen-backend.h index aac2fd454d..0f01631ae7 100644 --- a/include/hw/xen/xen-backend.h +++ b/include/hw/xen/xen-backend.h @@ -33,6 +33,7 @@ XenDevice *xen_backend_get_device(XenBackendInstance *bac= kend); void xen_backend_register(const XenBackendInfo *info); const char **xen_backend_get_types(unsigned int *nr); =20 +bool xen_backend_exists(const char *type, const char *name); void xen_backend_device_create(XenBus *xenbus, const char *type, const char *name, QDict *opts, Error **errp= ); bool xen_backend_try_device_destroy(XenDevice *xendev, Error **errp); --=20 2.40.1