Re: [PATCH v3] block/nvme: introduce PMR support from NVMe 1.4 spec

[Stefan Hajnoczi]

On Fri, Mar 20, 2020 at 5:48 PM Andrzej Jakowski
<address@hidden> wrote:
>
> On 3/20/20 8:45 AM, Stefan Hajnoczi wrote:
> > Please use qemu_ram_writeback() so that pmem_persist() and qemu_msync()
> > are used as appropriate.
>
> Thx!
> qemu_ram_writeback() doesn't return any status. How can I know that actual 
> msync succeds?

If the warn_report() message that is already printed by
qemu_ram_writeback() is insufficient in terms of error reporting, I
suggest propagating the return value from qemu_ram_writeback() and
qemu_ram_block_writeback().

> Also qemu_ram_writeback() requires me to include #include "exec/ram_addr.h".
> After including it when I compile code I'm getting following error:
>
> In file included from hw/block/nvme.c:49:
> /root/sources/pmr/qemu/include/exec/ram_addr.h:23:10: fatal error: cpu.h: No 
> such file or directory
>    23 | #include "cpu.h"
>       |          ^~~~~~~
> compilation terminated.
> make: *** [/root/sources/pmr/qemu/rules.mak:69: hw/block/nvme.o] Error 1
>
> Why this is happening and what should be changed.

Generally object files are built as part of common-obj-y in
Makefile.objs.  These object files are built only once across all QEMU
targets (e.g. qemu-system-x86_64, qemu-system-arm, ...).

Some code embeds target-specific information and is therefore not
suitable for common-obj-y.  These object files are built as part of
obj-y in Makefile.objs.

You can fix this compilation issue by changing hw/block/Makefile.objs
to like this:

diff --git a/hw/block/Makefile.objs b/hw/block/Makefile.objs
index 4b4a2b338d..12d5d5dac6 100644
--- a/hw/block/Makefile.objs
+++ b/hw/block/Makefile.objs
@@ -7,11 +7,11 @@ common-obj-$(CONFIG_PFLASH_CFI02) += pflash_cfi02.o
 common-obj-$(CONFIG_XEN) += xen-block.o
 common-obj-$(CONFIG_ECC) += ecc.o
 common-obj-$(CONFIG_ONENAND) += onenand.o
-common-obj-$(CONFIG_NVME_PCI) += nvme.o
 common-obj-$(CONFIG_SWIM) += swim.o

 common-obj-$(CONFIG_SH4) += tc58128.o

+obj-$(CONFIG_NVME_PCI) += nvme.o
 obj-$(CONFIG_VIRTIO_BLK) += virtio-blk.o
 obj-$(CONFIG_VHOST_USER_BLK) += vhost-user-blk.o

Stefan