From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 77E5471E7F for ; Wed, 30 Jun 2021 17:18:31 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 6D8821BA70 for ; Wed, 30 Jun 2021 17:18:31 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id A73431BA66 for ; Wed, 30 Jun 2021 17:18:29 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 76D0C430C0 for ; Wed, 30 Jun 2021 17:18:29 +0200 (CEST) From: Stefan Reiter To: pve-devel@lists.proxmox.com Date: Wed, 30 Jun 2021 17:18:17 +0200 Message-Id: <20210630151817.1707616-1-s.reiter@proxmox.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.705 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [qemuserver.pm, proxmox.com] Subject: [pve-devel] [PATCH qemu-server] cfg2cmd/drive: don't use io_uring for krbd with wb/wt cache X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Jun 2021 15:18:31 -0000 As reported here and locally reproduced: https://forum.proxmox.com/threads/efi-vms-wont-start-under-7-beta-with-writeback-cache.91629/ This configuration is currently broken. Until we figure out how to fix it properly, we can just have this (luckily very narrow) config pattern fall back to aio=threads as it used to. Signed-off-by: Stefan Reiter --- I tried my usual QEMU debugging routine, but couldn't figure anything specific out - it's not related to EFI, happens on SeaBIOS too, but looking at GDB just appears that it's waiting for the io_uring fd to become ready (in ppoll)... I did also test with a newer liburing (2.0 from git) but it didn't help. Anyway, until I figure it out (which may not happen until the release), let's work around with this, we can always roll this back later, as it doesn't break migration/snapshots to change 'aio' type. The forum post mentioned other SCSI controllers fixing the issue too, but that just confuses me even more, and we don't have that information available for cheap here, so I just made it fall back for all of them. PVE/QemuServer.pm | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm index 8af4176..f760467 100644 --- a/PVE/QemuServer.pm +++ b/PVE/QemuServer.pm @@ -1600,8 +1600,11 @@ sub print_drive_commandline_full { $cache_direct = 1; } + # io_uring with cache mode writeback or writethrough on krbd will hang... + my $rbd_no_io_uring = $scfg && $scfg->{type} eq 'rbd' && $scfg->{krbd} && !$cache_direct; + if (!$drive->{aio}) { - if ($io_uring) { + if ($io_uring && !$rbd_no_io_uring) { # io_uring supports all cache modes $opts .= ",aio=io_uring"; } else { -- 2.30.2