From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56344) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eDG2T-0005Ru-DA for qemu-devel@nongnu.org; Fri, 10 Nov 2017 15:36:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eDG2Q-0006tV-7u for qemu-devel@nongnu.org; Fri, 10 Nov 2017 15:36:33 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:54510 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eDG2Q-0005tj-1S for qemu-devel@nongnu.org; Fri, 10 Nov 2017 15:36:30 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vAAKZLbA056535 for ; Fri, 10 Nov 2017 15:35:29 -0500 Received: from e14.ny.us.ibm.com (e14.ny.us.ibm.com [129.33.205.204]) by mx0a-001b2d01.pphosted.com with ESMTP id 2e5du98drp-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 10 Nov 2017 15:35:28 -0500 Received: from localhost by e14.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 10 Nov 2017 15:35:27 -0500 From: Daniel Henrique Barboza Date: Fri, 10 Nov 2017 18:35:16 -0200 Message-Id: <20171110203516.17027-1-danielhb@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH v1] migration/ram.c: do not set 'postcopy_running' in POSTCOPY_INCOMING_END List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: mdroth@linux.vnet.ibm.com, quintela@redhat.com, dgilbert@redhat.com When migrating a VM with 'migrate_set_capability postcopy-ram on' a postcopy_state is set during the process, ending up with the state POSTCOPY_INCOMING_END when the migration is over. This postcopy_state is taken into account inside ram_load to check how it will load the memory pages. This same ram_load is called when in a loadvm command. Inside ram_load, the logic to see if we're at postcopy_running state is: postcopy_running = postcopy_state_get() >= POSTCOPY_INCOMING_LISTENING postcopy_state_get() returns this enum type: typedef enum { POSTCOPY_INCOMING_NONE = 0, POSTCOPY_INCOMING_ADVISE, POSTCOPY_INCOMING_DISCARD, POSTCOPY_INCOMING_LISTENING, POSTCOPY_INCOMING_RUNNING, POSTCOPY_INCOMING_END } PostcopyState; In the case where ram_load is executed and postcopy_state is POSTCOPY_INCOMING_END, postcopy_running will be set to 'true' and ram_load will behave like a postcopy is in progress. This scenario isn't achievable in a migration but it is reproducible when executing savevm/loadvm after migrating with 'postcopy-ram on', causing loadvm to fail with Error -22: Source: (qemu) migrate_set_capability postcopy-ram on (qemu) migrate tcp:127.0.0.1:4444 Dest: (qemu) migrate_set_capability postcopy-ram on (qemu) ubuntu1704-intel login: Ubuntu 17.04 ubuntu1704-intel ttyS0 ubuntu1704-intel login: (qemu) (qemu) savevm test1 (qemu) loadvm test1 Unknown combination of migration flags: 0x4 (postcopy mode) error while loading state for instance 0x0 of device 'ram' Error -22 while loading VM state (qemu) This patch fixes this problem by changing a bit the semantics of postcopy_running inside ram_load, verifying first if we're not in the POSTCOPY_INCOMING_END state. In this case, postcopy_running is set to 'false'. Signed-off-by: Daniel Henrique Barboza --- migration/ram.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 8620aa400a..43ed719668 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2803,13 +2803,21 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) int flags = 0, ret = 0, invalid_flags = 0; static uint64_t seq_iter; int len = 0; - /* - * If system is running in postcopy mode, page inserts to host memory must - * be atomic - */ - bool postcopy_running = postcopy_state_get() >= POSTCOPY_INCOMING_LISTENING; - /* ADVISE is earlier, it shows the source has the postcopy capability on */ - bool postcopy_advised = postcopy_state_get() >= POSTCOPY_INCOMING_ADVISE; + bool postcopy_advised = false, postcopy_running = false; + uint8_t postcopy_state = postcopy_state_get(); + + if (postcopy_state != POSTCOPY_INCOMING_END) { + /* + * If system is running in postcopy mode, page inserts to host memory + * must be atomic + */ + postcopy_running = postcopy_state >= POSTCOPY_INCOMING_LISTENING; + + /* ADVISE is earlier, it shows the source has the postcopy + * capability on + */ + postcopy_advised = postcopy_state >= POSTCOPY_INCOMING_ADVISE; + } seq_iter++; -- 2.13.6