The fields of the struct are naturally aligned, so this should be easy enough to fix just by dropping QEMU_PACKED (we already have a compile- time assert that the doorbells field is at the expected address).
NB: I notice also the struct is marked 'volatile' -- this is a bit of a red flag that the code may not really be doing the right thing here. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1817525 Title: qemu fails to compile on gcc 9 "block/nvme.c:209:22: error: taking address of packed member of 'struct <anonymous>' may result in an unaligned pointer value [-Werror=address-of-packed-member]" Status in QEMU: New Bug description: Issue: Qemu compilation fails with below error on ppc64le host with gcc 9, repo(https://github.com/dgibson/qemu.git), branch(ppc-for-4.0), Commit (0483e90393bac8546a1fbc95ab912a1e78e92b00) CHK version_gen.h CC block/nvme.o block/nvme.c: In function ‘nvme_create_queue_pair’: block/nvme.c:209:22: error: taking address of packed member of ‘struct <anonymous>’ may result in an unaligned pointer value [-Werror=address-of-packed-member] 209 | q->sq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale]; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ block/nvme.c:216:22: error: taking address of packed member of ‘struct <anonymous>’ may result in an unaligned pointer value [-Werror=address-of-packed-member] 216 | q->cq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale + 1]; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors make: *** [/usr/share/avocado-plugins-vt/build/qemu/rules.mak:69: block/nvme.o] Error 1 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ $git commit: commit 0483e90393bac8546a1fbc95ab912a1e78e92b00 (HEAD -> ppc-for-4.0) Author: Thomas Huth <th...@redhat.com> Date: Thu Feb 21 12:24:48 2019 +0100 hw/ppc: Use object_initialize_child for correct reference counting Both functions, object_initialize() and object_property_add_child() increase the reference counter of the new object, so one of the references has to be dropped afterwards to get the reference counting right. Otherwise the child object will not be properly cleaned up when the parent gets destroyed. Thus let's use now object_initialize_child() instead to get the reference counting here right. Suggested-by: Eduardo Habkost <ehabk...@redhat.com> Signed-off-by: Thomas Huth <th...@redhat.com> Message-Id: <1550748288-30598-1-git-send-email-th...@redhat.com> Reviewed-by: Cédric Le Goater <c...@kaod.org> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Note: Same commit on a different ppc64le host with gcc(8.1.1 20180712) compile without any issue. Host Env: Power8 #lscpu Architecture: ppc64le Byte Order: Little Endian CPU(s): 160 On-line CPU(s) list: 0,8,16,24,32,40,48,56,64,72,80,88,96,104,112,120,128,136,144,152 Off-line CPU(s) list: 1-7,9-15,17-23,25-31,33-39,41-47,49-55,57-63,65-71,73-79,81-87,89-95,97-103,105-111,113-119,121-127,129-135,137-143,145-151,153-159 Thread(s) per core: 1 Core(s) per socket: 5 Socket(s): 4 NUMA node(s): 4 Model: 2.1 (pvr 004b 0201) Model name: POWER8E (raw), altivec supported CPU max MHz: 3690.0000 CPU min MHz: 2061.0000 L1d cache: 64K L1i cache: 32K L2 cache: 512K L3 cache: 8192K NUMA node0 CPU(s): 0,8,16,24,32 NUMA node1 CPU(s): 40,48,56,64,72 NUMA node16 CPU(s): 80,88,96,104,112 NUMA node17 CPU(s): 120,128,136,144,152 # gcc --version gcc (GCC) 9.0.1 20190209 (Red Hat 9.0.1-0.4) Copyright (C) 2019 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. # uname -r 5.0.0-rc7-ge50585e89 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1817525/+subscriptions
