Digging a little further, the top-level meson.build for qemu has the
following:
if targetos == 'linux'
add_project_arguments('-isystem', meson.current_source_dir() /
'linux-headers',
'-isystem', 'linux-headers',
language: all_languages)
endif
But this does not carry to the subprojects (and there is nothing equivalent
in subprojects/libvhost-user/meson.build)/
If I change the above to use add_global_arguments() instead, compilation
succeeds.
I don´t know if this is going to break other things though, but I'd be
happy to change the patch to do that instead.
On Fri, Apr 7, 2023 at 11:29 AM David Turner <di...@google.com> wrote:
> So it looks like that for some reason, the QEMU linux-headers directory is
> not in the include search path for this compilation command, and that the
> system-or-sysroot provided <linux/vhost.h> is picked instead. Fixing this
> might be a better long-term fix than what I am proposing in this patch. I
> am not sure how to do that yet though. Do you have any recommendations?
>
>
> On Fri, Apr 7, 2023 at 11:25 AM David Turner <di...@google.com> wrote:
>
>> I meant glibc-2.17, I am using a sysroot to ensure the generated binaries
>> run on older Linux distributions.
>>
>> On Fri, Apr 7, 2023 at 11:24 AM David Turner <di...@google.com> wrote:
>>
>>> The <linux/vhost.h> of glib-2.17 begins with:
>>>
>>> #ifndef _LINUX_VHOST_H
>>> #define _LINUX_VHOST_H
>>> /* Userspace interface for in-kernel virtio accelerators. */
>>> /* vhost is used to reduce the number of system calls involved in virtio.
>>> *
>>> * Existing virtio net code is used in the guest without modification.
>>> *
>>> * This header includes interface used by userspace hypervisor for
>>> * device configuration.
>>> */
>>> #include <linux/types.h>
>>> #include <linux/ioctl.h>
>>> #include <linux/virtio_config.h>
>>> #include <linux/virtio_ring.h>
>>>
>>>
>>> See
>>> https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.17-4.8/+/refs/heads/master/sysroot/usr/include/linux/vhost.h
>>>
>>> Here's the compilation error I get in this case:
>>>
>>> FAILED: subprojects/libvhost-user/libvhost-user.a.p/libvhost-user.c.o
>>>
>>> /src/prebuilts/clang/clang-r487747/bin/clang --sysroot=/out/sysroot -m64
>>> -mcx16 -Isubprojects/libvhost-user/libvhost-user.a.p
>>> -Isubprojects/libvhost-user -I../../
>>> src/third_party/qemu/subprojects/libvhost-user
>>> -I/out/dest-install/usr/include -fcolor-diagnostics -Wall -Winvalid-pch
>>> -std=gnu99 -O2 -g -Wsign-compare -Wdeclarat
>>> ion-after-statement -Wstrict-aliasing -fno-pie -D_FILE_OFFSET_BITS=64
>>> -D_LARGEFILE_SOURCE -fno-strict-aliasing -fno-common -fwrapv -Wundef
>>> -Wwrite-strings -Wmissi
>>> ng-prototypes -Wstrict-prototypes -Wredundant-decls
>>> -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k
>>> -Winit-self -Wignored-qualifiers -Wempty-b
>>> ody -Wnested-externs -Wendif-labels -Wexpansion-to-defined
>>> -Wmissing-format-attribute -Wthread-safety -Wno-initializer-overrides
>>> -Wno-missing-include-dirs -Wno-sh
>>> ift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition
>>> -Wno-tautological-type-limit-compare -Wno-psabi
>>> -Wno-gnu-variable-sized-type-not-at-end -fstack-
>>> protector-strong -pthread -D_GNU_SOURCE -MD -MQ
>>> subprojects/libvhost-user/libvhost-user.a.p/libvhost-user.c.o -MF
>>> subprojects/libvhost-user/libvhost-user.a.p/libv
>>> host-user.c.o.d -o
>>> subprojects/libvhost-user/libvhost-user.a.p/libvhost-user.c.o -c
>>> ../../src/third_party/qemu/subprojects/libvhost-user/libvhost-user.c
>>>
>>> ../../src/third_party/qemu/subprojects/libvhost-user/libvhost-user.c:529:17:
>>> error: use of undeclared identifier 'VIRTIO_F_VERSION_1'
>>>
>>> 1ULL << VIRTIO_F_VERSION_1 |
>>>
>>> ^
>>> ../../src/third_party/qemu/subprojects/libvhost-user/libvhost-user.c:563:30:
>>> error: use of undeclared identifier 'VIRTIO_F_VERSION_1'
>>>
>>> if (!vu_has_feature(dev, VIRTIO_F_VERSION_1)) {
>>>
>>> ^
>>> ../../src/third_party/qemu/subprojects/libvhost-user/libvhost-user.c:632:22:
>>> warning: unused variable 'dev_region' [-Wunused-variable]
>>>
>>> VuDevRegion *dev_region = &dev->regions[i];
>>>
>>> ^
>>> ../../src/third_party/qemu/subprojects/libvhost-user/libvhost-user.c:633:13:
>>> warning: unused variable 'ret' [-Wunused-variable]
>>>
>>> int ret;
>>>
>>> ^
>>> 2 warnings and 2 errors generated.
>>>
>>>
>>> On Fri, Apr 7, 2023 at 10:03 AM Michael S. Tsirkin <m...@redhat.com>
>>> wrote:
>>>
>>>> If you are reposting, please version patchsets, E.g.
>>>> -v2 flag for git format-patch will enerate [PATCH v2] for you.
>>>>
>>>> Repeating what I said on previous version:
>>>>
>>>> On Wed, Apr 05, 2023 at 07:21:07PM +0200, David 'Digit' Turner wrote:
>>>> > The source file uses VIRTIO_F_VERSION_1 which is
>>>> > not defined by <linux/virtio_config.h> on Debian 10.
>>>> >
>>>> > The system-provided <linux/virtio_config.h> which
>>>> > does not include the macro definition is included
>>>> > through <linux/vhost.h>, so fix the issue by including
>>>> > the standard-headers version before that.
>>>> >
>>>> > Signed-off-by: David 'Digit' Turner <di...@google.com>
>>>>
>>>> This happens to work usually but there's no guarantee
>>>> "standard-headers/linux/virtio_config.h"
>>>> and <linux/virtio_config.h> are interchangeable or
>>>> even do not conflict.
>>>>
>>>> But where is <linux/vhost.h> using <linux/virtio_config.h>?
>>>> Everyone should be using "standard-headers/linux/virtio_config.h".
>>>>
>>>>
>>>> > ---
>>>> > subprojects/libvhost-user/libvhost-user.c | 6 ++++++
>>>> > 1 file changed, 6 insertions(+)
>>>> >
>>>> > diff --git a/subprojects/libvhost-user/libvhost-user.c
>>>> b/subprojects/libvhost-user/libvhost-user.c
>>>> > index 0200b78e8e..0a5768cb55 100644
>>>> > --- a/subprojects/libvhost-user/libvhost-user.c
>>>> > +++ b/subprojects/libvhost-user/libvhost-user.c
>>>> > @@ -32,6 +32,12 @@
>>>> > #include <sys/mman.h>
>>>> > #include <endian.h>
>>>> >
>>>> > +/* Necessary to provide VIRTIO_F_VERSION_1 on system
>>>> > + * with older linux headers. Must appear before
>>>> > + * <linux/vhost.h> below.
>>>> > + */
>>>> > +#include "standard-headers/linux/virtio_config.h"
>>>> > +
>>>> > #if defined(__linux__)
>>>> > #include <sys/syscall.h>
>>>> > #include <fcntl.h>
>>>> > --
>>>> > 2.40.0.348.gf938b09366-goog
>>>>
>>>>
