From patchwork Wed Dec 11 15:29:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11285391 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 87170138D for ; Wed, 11 Dec 2019 15:31:13 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 63C762173E for ; Wed, 11 Dec 2019 15:31:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="cTSKbM41" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63C762173E Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1if3wI-00026U-I9; Wed, 11 Dec 2019 15:30:10 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1if3wI-00026E-1Q for xen-devel@lists.xenproject.org; Wed, 11 Dec 2019 15:30:10 +0000 X-Inumbo-ID: 1becc234-1c2b-11ea-8b7d-12813bfff9fa Received: from smtp-fw-4101.amazon.com (unknown [72.21.198.25]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 1becc234-1c2b-11ea-8b7d-12813bfff9fa; Wed, 11 Dec 2019 15:30:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1576078207; x=1607614207; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=iUa3rMrxmsbf7wqyelx7uKp4w0L5PGnWaAJKZ1+2hRA=; b=cTSKbM41K5a+TpaQu2fopTrSOifueqCyPZ1HkG+kaBqU9sgD8BOFjW+c Msa66gq/9iug/gF0j0UOq7wByZ465T0LMJXKpqvpO2iTY8+FrD+IykA/t PpD7nvTh8VKzBh73ZEArTRgYzb7g5tiOaboJHp4x/dZne5eFlzJ55s1qw c=; IronPort-SDR: k+ahKTZHIO0ciIGn4hMaP6zVJRPspOxO/cgWgiMFZcQpLsQqkQ6c1rHpCPrZg2+A0/TfDf2Ix1 0d4IQXOJvoNw== X-IronPort-AV: E=Sophos;i="5.69,301,1571702400"; d="scan'208";a="8046829" Received: from iad6-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-69849ee2.us-west-2.amazon.com) ([10.124.125.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 11 Dec 2019 15:30:06 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2a-69849ee2.us-west-2.amazon.com (Postfix) with ESMTPS id 2B8E7A245B; Wed, 11 Dec 2019 15:30:05 +0000 (UTC) Received: from EX13D32EUC001.ant.amazon.com (10.43.164.159) by EX13MTAUEA001.ant.amazon.com (10.43.61.243) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:04 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D32EUC001.ant.amazon.com (10.43.164.159) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:03 +0000 Received: from u2f063a87eabd5f.cbg10.amazon.com (10.125.106.135) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Wed, 11 Dec 2019 15:30:01 +0000 From: Paul Durrant To: , , Date: Wed, 11 Dec 2019 15:29:53 +0000 Message-ID: <20191211152956.5168-2-pdurrant@amazon.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191211152956.5168-1-pdurrant@amazon.com> References: <20191211152956.5168-1-pdurrant@amazon.com> MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v3 1/4] xenbus: move xenbus_dev_shutdown() into frontend code... X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Paul Durrant , Stefano Stabellini , Boris Ostrovsky Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" ...and make it static xenbus_dev_shutdown() is seemingly intended to cause clean shutdown of PV frontends when a guest is rebooted. Indeed the function waits for a conpletion which is only set by a call to xenbus_frontend_closed(). This patch removes the shutdown() method from backends and moves xenbus_dev_shutdown() from xenbus_probe.c into xenbus_probe_frontend.c, renaming it appropriately and making it static. NOTE: In the case where the backend is running in a driver domain, the toolstack should have already terminated any frontends that may be using it (since Xen does not support re-startable PV driver domains) so xenbus_dev_shutdown() should never be called. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross --- Cc: Boris Ostrovsky Cc: Stefano Stabellini --- drivers/xen/xenbus/xenbus.h | 2 -- drivers/xen/xenbus/xenbus_probe.c | 23 --------------------- drivers/xen/xenbus/xenbus_probe_backend.c | 1 - drivers/xen/xenbus/xenbus_probe_frontend.c | 24 +++++++++++++++++++++- 4 files changed, 23 insertions(+), 27 deletions(-) diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h index d75a2385b37c..5f5b8a7d5b80 100644 --- a/drivers/xen/xenbus/xenbus.h +++ b/drivers/xen/xenbus/xenbus.h @@ -116,8 +116,6 @@ int xenbus_probe_devices(struct xen_bus_type *bus); void xenbus_dev_changed(const char *node, struct xen_bus_type *bus); -void xenbus_dev_shutdown(struct device *_dev); - int xenbus_dev_suspend(struct device *dev); int xenbus_dev_resume(struct device *dev); int xenbus_dev_cancel(struct device *dev); diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index c21be6e9d38a..5aa29396c9e3 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -281,29 +281,6 @@ int xenbus_dev_remove(struct device *_dev) } EXPORT_SYMBOL_GPL(xenbus_dev_remove); -void xenbus_dev_shutdown(struct device *_dev) -{ - struct xenbus_device *dev = to_xenbus_device(_dev); - unsigned long timeout = 5*HZ; - - DPRINTK("%s", dev->nodename); - - get_device(&dev->dev); - if (dev->state != XenbusStateConnected) { - pr_info("%s: %s: %s != Connected, skipping\n", - __func__, dev->nodename, xenbus_strstate(dev->state)); - goto out; - } - xenbus_switch_state(dev, XenbusStateClosing); - timeout = wait_for_completion_timeout(&dev->down, timeout); - if (!timeout) - pr_info("%s: %s timeout closing device\n", - __func__, dev->nodename); - out: - put_device(&dev->dev); -} -EXPORT_SYMBOL_GPL(xenbus_dev_shutdown); - int xenbus_register_driver_common(struct xenbus_driver *drv, struct xen_bus_type *bus, struct module *owner, const char *mod_name) diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c index b0bed4faf44c..14876faff3b0 100644 --- a/drivers/xen/xenbus/xenbus_probe_backend.c +++ b/drivers/xen/xenbus/xenbus_probe_backend.c @@ -198,7 +198,6 @@ static struct xen_bus_type xenbus_backend = { .uevent = xenbus_uevent_backend, .probe = xenbus_dev_probe, .remove = xenbus_dev_remove, - .shutdown = xenbus_dev_shutdown, .dev_groups = xenbus_dev_groups, }, }; diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c index a7d90a719cea..8a1650bbe18f 100644 --- a/drivers/xen/xenbus/xenbus_probe_frontend.c +++ b/drivers/xen/xenbus/xenbus_probe_frontend.c @@ -126,6 +126,28 @@ static int xenbus_frontend_dev_probe(struct device *dev) return xenbus_dev_probe(dev); } +static void xenbus_frontend_dev_shutdown(struct device *_dev) +{ + struct xenbus_device *dev = to_xenbus_device(_dev); + unsigned long timeout = 5*HZ; + + DPRINTK("%s", dev->nodename); + + get_device(&dev->dev); + if (dev->state != XenbusStateConnected) { + pr_info("%s: %s: %s != Connected, skipping\n", + __func__, dev->nodename, xenbus_strstate(dev->state)); + goto out; + } + xenbus_switch_state(dev, XenbusStateClosing); + timeout = wait_for_completion_timeout(&dev->down, timeout); + if (!timeout) + pr_info("%s: %s timeout closing device\n", + __func__, dev->nodename); + out: + put_device(&dev->dev); +} + static const struct dev_pm_ops xenbus_pm_ops = { .suspend = xenbus_dev_suspend, .resume = xenbus_frontend_dev_resume, @@ -146,7 +168,7 @@ static struct xen_bus_type xenbus_frontend = { .uevent = xenbus_uevent_frontend, .probe = xenbus_frontend_dev_probe, .remove = xenbus_dev_remove, - .shutdown = xenbus_dev_shutdown, + .shutdown = xenbus_frontend_dev_shutdown, .dev_groups = xenbus_dev_groups, .pm = &xenbus_pm_ops, From patchwork Wed Dec 11 15:29:54 2019 Content-Type: text/plain; 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d="scan'208";a="8046840" Received: from iad6-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-6e2fc477.us-west-2.amazon.com) ([10.124.125.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 11 Dec 2019 15:30:09 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2a-6e2fc477.us-west-2.amazon.com (Postfix) with ESMTPS id 32C03A2C58; Wed, 11 Dec 2019 15:30:08 +0000 (UTC) Received: from EX13D32EUB002.ant.amazon.com (10.43.166.114) by EX13MTAUEA001.ant.amazon.com (10.43.61.243) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:07 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D32EUB002.ant.amazon.com (10.43.166.114) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:06 +0000 Received: from u2f063a87eabd5f.cbg10.amazon.com (10.125.106.135) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Wed, 11 Dec 2019 15:30:04 +0000 From: Paul Durrant To: , , Date: Wed, 11 Dec 2019 15:29:54 +0000 Message-ID: <20191211152956.5168-3-pdurrant@amazon.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191211152956.5168-1-pdurrant@amazon.com> References: <20191211152956.5168-1-pdurrant@amazon.com> MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v3 2/4] xenbus: limit when state is forced to closed X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Paul Durrant , Stefano Stabellini , Boris Ostrovsky Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" If a driver probe() fails then leave the xenstore state alone. There is no reason to modify it as the failure may be due to transient resource allocation issues and hence a subsequent probe() may succeed. If the driver supports re-binding then only force state to closed during remove() only in the case when the toolstack may need to clean up. This can be detected by checking whether the state in xenstore has been set to closing prior to device removal. NOTE: Re-bind support is indicated by new boolean in struct xenbus_driver, which defaults to false. Subsequent patches will add support to some backend drivers. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross --- Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini v2: - Introduce the 'allow_rebind' flag - Expand the commit comment --- drivers/xen/xenbus/xenbus_probe.c | 12 ++++++++++-- include/xen/xenbus.h | 1 + 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index 5aa29396c9e3..378486b79f96 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -255,7 +255,6 @@ int xenbus_dev_probe(struct device *_dev) module_put(drv->driver.owner); fail: xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename); - xenbus_switch_state(dev, XenbusStateClosed); return err; } EXPORT_SYMBOL_GPL(xenbus_dev_probe); @@ -276,7 +275,16 @@ int xenbus_dev_remove(struct device *_dev) free_otherend_details(dev); - xenbus_switch_state(dev, XenbusStateClosed); + /* + * If the toolstack has forced the device state to closing then set + * the state to closed now to allow it to be cleaned up. + * Similarly, if the driver does not support re-bind, set the + * closed. + */ + if (!drv->allow_rebind || + xenbus_read_driver_state(dev->nodename) == XenbusStateClosing) + xenbus_switch_state(dev, XenbusStateClosed); + return 0; } EXPORT_SYMBOL_GPL(xenbus_dev_remove); diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index 869c816d5f8c..24228a102141 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -93,6 +93,7 @@ struct xenbus_device_id struct xenbus_driver { const char *name; /* defaults to ids[0].devicetype */ const struct xenbus_device_id *ids; + bool allow_rebind; /* avoid setting xenstore closed during remove */ int (*probe)(struct xenbus_device *dev, const struct xenbus_device_id *id); void (*otherend_changed)(struct xenbus_device *dev, From patchwork Wed Dec 11 15:29:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11285397 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 63F65109A for ; Wed, 11 Dec 2019 15:31:56 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 40F1A208C3 for ; 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Wed, 11 Dec 2019 15:30:39 +0000 (UTC) Received: from EX13D32EUB004.ant.amazon.com (10.43.166.212) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:10 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D32EUB004.ant.amazon.com (10.43.166.212) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:10 +0000 Received: from u2f063a87eabd5f.cbg10.amazon.com (10.125.106.135) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Wed, 11 Dec 2019 15:30:07 +0000 From: Paul Durrant To: , , Date: Wed, 11 Dec 2019 15:29:55 +0000 Message-ID: <20191211152956.5168-4-pdurrant@amazon.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191211152956.5168-1-pdurrant@amazon.com> References: <20191211152956.5168-1-pdurrant@amazon.com> MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v3 3/4] xen/interface: re-define FRONT/BACK_RING_ATTACH() X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Paul Durrant , Stefano Stabellini , Boris Ostrovsky Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Currently these macros are defined to re-initialize a front/back ring (respectively) to values read from the shared ring in such a way that any requests/responses that are added to the shared ring whilst the front/back is detached will be skipped over. This, in general, is not a desirable semantic since most frontend implementations will eventually block waiting for a response which would either never appear or never be processed. Since the macros are currently unused, take this opportunity to re-define them to re-initialize a front/back ring using specified values. This also allows FRONT/BACK_RING_INIT() to be re-defined in terms of FRONT/BACK_RING_ATTACH() using a specified value of 0. NOTE: BACK_RING_ATTACH() will be used directly in a subsequent patch. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross --- Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini A patch to add the FRONT/BACK_RING_ATTACH() macros to the canonical ring.h in xen.git will be sent once the definitions have been agreed. v2: - change definitions to take explicit initial index values --- include/xen/interface/io/ring.h | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h index 3f40501fc60b..2af7a1cd6658 100644 --- a/include/xen/interface/io/ring.h +++ b/include/xen/interface/io/ring.h @@ -125,35 +125,24 @@ struct __name##_back_ring { \ memset((_s)->pad, 0, sizeof((_s)->pad)); \ } while(0) -#define FRONT_RING_INIT(_r, _s, __size) do { \ - (_r)->req_prod_pvt = 0; \ - (_r)->rsp_cons = 0; \ +#define FRONT_RING_ATTACH(_r, _s, _i, __size) do { \ + (_r)->req_prod_pvt = (_i); \ + (_r)->rsp_cons = (_i); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \ (_r)->sring = (_s); \ } while (0) -#define BACK_RING_INIT(_r, _s, __size) do { \ - (_r)->rsp_prod_pvt = 0; \ - (_r)->req_cons = 0; \ - (_r)->nr_ents = __RING_SIZE(_s, __size); \ - (_r)->sring = (_s); \ -} while (0) +#define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size) -/* Initialize to existing shared indexes -- for recovery */ -#define FRONT_RING_ATTACH(_r, _s, __size) do { \ - (_r)->sring = (_s); \ - (_r)->req_prod_pvt = (_s)->req_prod; \ - (_r)->rsp_cons = (_s)->rsp_prod; \ +#define BACK_RING_ATTACH(_r, _s, _i, __size) do { \ + (_r)->rsp_prod_pvt = (_i); \ + (_r)->req_cons = (_i); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \ -} while (0) - -#define BACK_RING_ATTACH(_r, _s, __size) do { \ (_r)->sring = (_s); \ - (_r)->rsp_prod_pvt = (_s)->rsp_prod; \ - (_r)->req_cons = (_s)->req_prod; \ - (_r)->nr_ents = __RING_SIZE(_s, __size); \ } while (0) +#define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size) + /* How big is this ring? */ #define RING_SIZE(_r) \ ((_r)->nr_ents) From patchwork Wed Dec 11 15:29:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11285395 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 17EBA138D for ; Wed, 11 Dec 2019 15:31:53 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E8DE9208C3 for ; Wed, 11 Dec 2019 15:31:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="AuDXomJ8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E8DE9208C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1if3x7-0002I4-6O; Wed, 11 Dec 2019 15:31:01 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1if3x5-0002Hd-MH for xen-devel@lists.xenproject.org; Wed, 11 Dec 2019 15:30:59 +0000 X-Inumbo-ID: 3afb046a-1c2b-11ea-8b7d-12813bfff9fa Received: from smtp-fw-9102.amazon.com (unknown [207.171.184.29]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 3afb046a-1c2b-11ea-8b7d-12813bfff9fa; Wed, 11 Dec 2019 15:30:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1576078260; x=1607614260; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=N22hyGYPk1JoqY1Qt0Vz9EReiYVT9fCIbFq3JobjLc4=; b=AuDXomJ8oVIS6tS4/APUnJexaGL775UVH5enq+bAE0IJuDKCYqZs985j K26jNkiVZikPBOLkelkZmLh59tbWtCWsLNVsx/0PRt9c+jECXRjEsTVJT xpFpsFfP57SiBgEVKKLCo9dVPsSMhZyl3suiXuiGqxqAbozIaUJBhFTr2 8=; IronPort-SDR: J9/38YbMpalD44EqUzMsZ76zibWP7tf+mT+iXkGgPFEVIRtKljVza3qOgqGg0rbr/3/l0JZmLp 5vb/yvqk5YQQ== X-IronPort-AV: E=Sophos;i="5.69,301,1571702400"; d="scan'208";a="12930184" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-2b-81e76b79.us-west-2.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP; 11 Dec 2019 15:30:47 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan3.pdx.amazon.com [10.170.41.166]) by email-inbound-relay-2b-81e76b79.us-west-2.amazon.com (Postfix) with ESMTPS id 7A6AFA2173; Wed, 11 Dec 2019 15:30:46 +0000 (UTC) Received: from EX13D32EUB002.ant.amazon.com (10.43.166.114) by EX13MTAUEA001.ant.amazon.com (10.43.61.243) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:14 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D32EUB002.ant.amazon.com (10.43.166.114) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 11 Dec 2019 15:30:13 +0000 Received: from u2f063a87eabd5f.cbg10.amazon.com (10.125.106.135) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Wed, 11 Dec 2019 15:30:10 +0000 From: Paul Durrant To: , , Date: Wed, 11 Dec 2019 15:29:56 +0000 Message-ID: <20191211152956.5168-5-pdurrant@amazon.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191211152956.5168-1-pdurrant@amazon.com> References: <20191211152956.5168-1-pdurrant@amazon.com> MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v3 4/4] xen-blkback: support dynamic unbind/bind X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Juergen Gross , Stefano Stabellini , Konrad Rzeszutek Wilk , Paul Durrant , Boris Ostrovsky , =?utf-8?q?Roger_Pau_Monn?= =?utf-8?q?=C3=A9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" By simply re-attaching to shared rings during connect_ring() rather than assuming they are freshly allocated (i.e assuming the counters are zero) it is possible for vbd instances to be unbound and re-bound from and to (respectively) a running guest. This has been tested by running: while true; do fio --name=randwrite --ioengine=libaio --iodepth=16 \ --rw=randwrite --bs=4k --direct=1 --size=1G --verify=crc32; done in a PV guest whilst running: while true; do echo vbd-$DOMID-$VBD >unbind; echo unbound; sleep 5; echo vbd-$DOMID-$VBD >bind; echo bound; sleep 3; done in dom0 from /sys/bus/xen-backend/drivers/vbd to continuously unbind and re-bind its system disk image. This is a highly useful feature for a backend module as it allows it to be unloaded and re-loaded (i.e. updated) without requiring domUs to be halted. This was also tested by running: while true; do echo vbd-$DOMID-$VBD >unbind; echo unbound; sleep 5; rmmod xen-blkback; echo unloaded; sleep 1; modprobe xen-blkback; echo bound; cd $(pwd); sleep 3; done in dom0 whilst running the same loop as above in the (single) PV guest. Some (less stressful) testing has also been done using a Windows HVM guest with the latest 9.0 PV drivers installed. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Reviewed-by: Roger Pau Monné --- Cc: Konrad Rzeszutek Wilk Cc: "Roger Pau Monné" Cc: Jens Axboe Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini v3: - Constify sring_common and re-work error handling in xen_blkif_map() v2: - Apply a sanity check to the value of rsp_prod and fail the re-attach if it is implausible - Set allow_rebind to prevent ring from being closed on unbind - Update test workload from dd to fio (with verification) --- drivers/block/xen-blkback/xenbus.c | 56 ++++++++++++++++++++---------- 1 file changed, 38 insertions(+), 18 deletions(-) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 59d576d27ca7..0d4097bdff3f 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -190,6 +190,9 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, { int err; struct xen_blkif *blkif = ring->blkif; + const struct blkif_common_sring *sring_common; + RING_IDX rsp_prod, req_prod; + unsigned int size; /* Already connected through? */ if (ring->irq) @@ -200,46 +203,62 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, if (err < 0) return err; + sring_common = (struct blkif_common_sring *)ring->blk_ring; + rsp_prod = READ_ONCE(sring_common->rsp_prod); + req_prod = READ_ONCE(sring_common->req_prod); + switch (blkif->blk_protocol) { case BLKIF_PROTOCOL_NATIVE: { - struct blkif_sring *sring; - sring = (struct blkif_sring *)ring->blk_ring; - BACK_RING_INIT(&ring->blk_rings.native, sring, - XEN_PAGE_SIZE * nr_grefs); + struct blkif_sring *sring_native = + (struct blkif_sring *)ring->blk_ring; + + BACK_RING_ATTACH(&ring->blk_rings.native, sring_native, + rsp_prod, XEN_PAGE_SIZE * nr_grefs); + size = __RING_SIZE(sring_native, XEN_PAGE_SIZE * nr_grefs); break; } case BLKIF_PROTOCOL_X86_32: { - struct blkif_x86_32_sring *sring_x86_32; - sring_x86_32 = (struct blkif_x86_32_sring *)ring->blk_ring; - BACK_RING_INIT(&ring->blk_rings.x86_32, sring_x86_32, - XEN_PAGE_SIZE * nr_grefs); + struct blkif_x86_32_sring *sring_x86_32 = + (struct blkif_x86_32_sring *)ring->blk_ring; + + BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32, + rsp_prod, XEN_PAGE_SIZE * nr_grefs); + size = __RING_SIZE(sring_x86_32, XEN_PAGE_SIZE * nr_grefs); break; } case BLKIF_PROTOCOL_X86_64: { - struct blkif_x86_64_sring *sring_x86_64; - sring_x86_64 = (struct blkif_x86_64_sring *)ring->blk_ring; - BACK_RING_INIT(&ring->blk_rings.x86_64, sring_x86_64, - XEN_PAGE_SIZE * nr_grefs); + struct blkif_x86_64_sring *sring_x86_64 = + (struct blkif_x86_64_sring *)ring->blk_ring; + + BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64, + rsp_prod, XEN_PAGE_SIZE * nr_grefs); + size = __RING_SIZE(sring_x86_64, XEN_PAGE_SIZE * nr_grefs); break; } default: BUG(); } + err = -EIO; + if (req_prod - rsp_prod > size) + goto fail; + err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, xen_blkif_be_int, 0, "blkif-backend", ring); - if (err < 0) { - xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); - ring->blk_rings.common.sring = NULL; - return err; - } + if (err < 0) + goto fail; ring->irq = err; return 0; + +fail: + xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); + ring->blk_rings.common.sring = NULL; + return err; } static int xen_blkif_disconnect(struct xen_blkif *blkif) @@ -1131,7 +1150,8 @@ static struct xenbus_driver xen_blkbk_driver = { .ids = xen_blkbk_ids, .probe = xen_blkbk_probe, .remove = xen_blkbk_remove, - .otherend_changed = frontend_changed + .otherend_changed = frontend_changed, + .allow_rebind = true, }; int xen_blkif_xenbus_init(void)