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x-sender="anthony.perard@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ~all" Received-SPF: None (esa6.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="anthony.perard@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: Dre/avdhM7+LkeeYNgXPxCnkXilAmFPsNzT4qdmjCyNlv3RbAuMOhVn8Hnt589TC2ULQAyStmJ wztSwrqA0slgsaYkaxu90dU3UyfmxOHqd0ywcZ+98kK+RjFO9FYLuJIE8r0tRR/Gn7YVBB4lqB b6iSUVXUkjPwrJUtVz621eni4MLaOxm7efr/gQJaNhCkecfQ5HGEJ5VuHoNh6x87n95f+58EuQ 1tNsyO2VabwmwuQl/amP+KFPELiUvI3GQAooAUS887cQnyBt9uPiTpot6St8gekcuXoRKO+e2D PLI= X-SBRS: 2.7 X-MesageID: 4731850 X-Ironport-Server: esa6.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.64,412,1559534400"; d="scan'208";a="4731850" From: Anthony PERARD To: Date: Wed, 21 Aug 2019 10:20:19 +0100 Message-ID: <20190821092020.17952-2-anthony.perard@citrix.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190821092020.17952-1-anthony.perard@citrix.com> References: <20190821092020.17952-1-anthony.perard@citrix.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x X-Received-From: 216.71.155.175 Subject: [Qemu-devel] [PATCH 1/2] xen-bus: Fix backend state transition on device reset X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Anthony PERARD , xen-devel@lists.xenproject.org, Stefano Stabellini , qemu-stable@nongnu.org, Paul Durrant Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" When a frontend want to reset its state and the backend one, it start with setting "Closing", then wait for the backend (QEMU) to do the same. But when QEMU is setting "Closing" to its state, it trigger an event (xenstore watch) that re-execute xen_device_backend_changed() and set the backend state to "Closed". QEMU should wait for the frontend to set "Closed" before doing the same. Before setting "Closed" to the backend_state, we are also going to check if the frontend was responsible for the transition to "Closing". Fixes: b6af8926fb858c4f1426e5acb2cfc1f0580ec98a Signed-off-by: Anthony PERARD --- Cc: qemu-stable@nongnu.org --- hw/xen/xen-bus.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index e40500242d..982eca4533 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -540,9 +540,11 @@ static void xen_device_backend_changed(void *opaque) /* * If the toolstack (or unplug request callback) has set the backend * state to Closing, but there is no active frontend (i.e. the - * state is not Connected) then set the backend state to Closed. + * state is not Connected or Closing) then set the backend state + * to Closed. */ if (xendev->backend_state == XenbusStateClosing && + xendev->frontend_state != XenbusStateClosing && xendev->frontend_state != XenbusStateConnected) { xen_device_backend_set_state(xendev, XenbusStateClosed); } From patchwork Wed Aug 21 09:20:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony PERARD X-Patchwork-Id: 11106185 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3876114DB for ; 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spf=Pass smtp.mailfrom=anthony.perard@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa6.hc3370-68.iphmx.com: no sender authenticity information available from domain of anthony.perard@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="anthony.perard@citrix.com"; x-sender="anthony.perard@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa6.hc3370-68.iphmx.com: domain of anthony.perard@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="anthony.perard@citrix.com"; x-sender="anthony.perard@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ~all" Received-SPF: None (esa6.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="anthony.perard@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: WfjGDj2DQFiJy54qdsaOgrVkQw3aWiHlsoBLNpBt2U248THIHc0Y8riEu/v4C7ZiixdnbUtqVz P7C55PalBoVq1dTW8NTiC5YMfvoghAdjR2vZ6Yh5i85o7QDyyJwMdXJ6dadkZnMRRbvp3Su9Tm vpSAc+zamMqDQnOWIQP8lN9v9z673ja0WxAsyn+0WrJLMuVRwWD5q38ilHA7g+zWEkWxsH8aIi Z3hE7/sV4H3dBg/eeYjP6eNDuE4NkHWj3Ojfia/zOWkQmdPryzHwrzvyCQ0FvIISAUydX0ytaB ZFM= X-SBRS: 2.7 X-MesageID: 4731852 X-Ironport-Server: esa6.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.64,412,1559534400"; d="scan'208";a="4731852" From: Anthony PERARD To: Date: Wed, 21 Aug 2019 10:20:20 +0100 Message-ID: <20190821092020.17952-3-anthony.perard@citrix.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190821092020.17952-1-anthony.perard@citrix.com> References: <20190821092020.17952-1-anthony.perard@citrix.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x X-Received-From: 216.71.155.175 Subject: [Qemu-devel] [PATCH 2/2] xen-bus: Avoid rewriting identical values to xenstore X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Anthony PERARD , xen-devel@lists.xenproject.org, Stefano Stabellini , Paul Durrant Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" When QEMU receive a xenstore watch event suggesting that the "state" or "online" status of the frontend or the backend changed, it record this in its own state but it also re-write the value back into xenstore even so there were no changed. This trigger an unnecessary xenstore watch event which QEMU will process again (and maybe the frontend as well). Signed-off-by: Anthony PERARD --- hw/xen/xen-bus.c | 37 ++++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-) diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index 982eca4533..c83f07424a 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -481,20 +481,27 @@ static int xen_device_backend_scanf(XenDevice *xendev, const char *key, return rc; } -void xen_device_backend_set_state(XenDevice *xendev, - enum xenbus_state state) +static bool xen_device_backend_record_state(XenDevice *xendev, + enum xenbus_state state) { const char *type = object_get_typename(OBJECT(xendev)); if (xendev->backend_state == state) { - return; + return false; } trace_xen_device_backend_state(type, xendev->name, xs_strstate(state)); xendev->backend_state = state; - xen_device_backend_printf(xendev, "state", "%u", state); + return true; +} + +void xen_device_backend_set_state(XenDevice *xendev, + enum xenbus_state state) +{ + if (xen_device_backend_record_state(xendev, state)) + xen_device_backend_printf(xendev, "state", "%u", state); } enum xenbus_state xen_device_backend_get_state(XenDevice *xendev) @@ -502,7 +509,8 @@ enum xenbus_state xen_device_backend_get_state(XenDevice *xendev) return xendev->backend_state; } -static void xen_device_backend_set_online(XenDevice *xendev, bool online) +static void xen_device_backend_set_online(XenDevice *xendev, bool online, + bool export) { const char *type = object_get_typename(OBJECT(xendev)); @@ -513,7 +521,8 @@ static void xen_device_backend_set_online(XenDevice *xendev, bool online) trace_xen_device_backend_online(type, xendev->name, online); xendev->backend_online = online; - xen_device_backend_printf(xendev, "online", "%u", online); + if (export) + xen_device_backend_printf(xendev, "online", "%u", online); } static void xen_device_backend_changed(void *opaque) @@ -529,13 +538,13 @@ static void xen_device_backend_changed(void *opaque) state = XenbusStateUnknown; } - xen_device_backend_set_state(xendev, state); + xen_device_backend_record_state(xendev, state); if (xen_device_backend_scanf(xendev, "online", "%u", &online) != 1) { online = 0; } - xen_device_backend_set_online(xendev, !!online); + xen_device_backend_set_online(xendev, !!online, false); /* * If the toolstack (or unplug request callback) has set the backend @@ -683,7 +692,8 @@ int xen_device_frontend_scanf(XenDevice *xendev, const char *key, } static void xen_device_frontend_set_state(XenDevice *xendev, - enum xenbus_state state) + enum xenbus_state state, + bool export) { const char *type = object_get_typename(OBJECT(xendev)); @@ -695,7 +705,8 @@ static void xen_device_frontend_set_state(XenDevice *xendev, xs_strstate(state)); xendev->frontend_state = state; - xen_device_frontend_printf(xendev, "state", "%u", state); + if (export) + xen_device_frontend_printf(xendev, "state", "%u", state); } static void xen_device_frontend_changed(void *opaque) @@ -711,7 +722,7 @@ static void xen_device_frontend_changed(void *opaque) state = XenbusStateUnknown; } - xen_device_frontend_set_state(xendev, state); + xen_device_frontend_set_state(xendev, state, false); if (state == XenbusStateInitialising && xendev->backend_state == XenbusStateClosed && @@ -1146,7 +1157,7 @@ static void xen_device_realize(DeviceState *dev, Error **errp) xendev->frontend_id); xen_device_backend_printf(xendev, "hotplug-status", "connected"); - xen_device_backend_set_online(xendev, true); + xen_device_backend_set_online(xendev, true, true); xen_device_backend_set_state(xendev, XenbusStateInitWait); xen_device_frontend_printf(xendev, "backend", "%s", @@ -1154,7 +1165,7 @@ static void xen_device_realize(DeviceState *dev, Error **errp) xen_device_frontend_printf(xendev, "backend-id", "%u", xenbus->backend_id); - xen_device_frontend_set_state(xendev, XenbusStateInitialising); + xen_device_frontend_set_state(xendev, XenbusStateInitialising, true); xendev->exit.notify = xen_device_exit; qemu_add_exit_notifier(&xendev->exit);