Re: [PATCH] tools/virtio: Test virtual address range detection

[Michael S. Tsirkin]

On Wed, Mar 16, 2022 at 02:41:35PM +0000, Matthew Wilcox wrote:
> On Tue, Feb 22, 2022 at 11:18:18PM +0000, Matthew Wilcox wrote:
> > On Tue, Feb 22, 2022 at 07:58:33AM +0000, David Woodhouse wrote:
> > > On Tue, 2022-02-22 at 01:31 -0500, Michael S. Tsirkin wrote:
> > > > On Mon, Feb 21, 2022 at 05:18:48PM +0000, David Woodhouse wrote:
> > > > > 
> > > > > [dwoodhou@i7 virtio]$ sudo ~/virtio_test
> > > > > Detected virtual address range 0x1000-0x7ffffffff000
> > > > > spurious wakeups: 0x0 started=0x100000 completed=0x100000
> > > > > 
> > > > > Although in some circumstances I also see a different build failure:
> > > > > 
> > > > > cc -g -O2 -Werror -Wno-maybe-uninitialized -Wall -I. -I../include/ -I ../../usr/include/ -Wno-pointer-sign -fno-strict-overflow -fno-strict-aliasing -fno-common -MMD -U_FORTIFY_SOURCE -include ../../include/linux/kconfig.h   -c -o vringh_test.o vringh_test.c
> > 
> > Trying to test this myself ...
> > 
> > $ cd tools/virtio/
> > $ make
> > ...
> > cc -lpthread  virtio_test.o virtio_ring.o   -o virtio_test
> > /usr/bin/ld: virtio_ring.o: in function `spin_lock':
> > /home/willy/kernel/folio/tools/virtio/./linux/spinlock.h:16: undefined reference to `pthread_spin_lock'
> > 
> > So this is not the only problem here?
> 
> FYI, this fixes it for me:
> 
> diff --git a/tools/virtio/Makefile b/tools/virtio/Makefile
> index 0d7bbe49359d..83b6a522d0d2 100644
> --- a/tools/virtio/Makefile
> +++ b/tools/virtio/Makefile
> @@ -5,7 +5,7 @@ virtio_test: virtio_ring.o virtio_test.o
>  vringh_test: vringh_test.o vringh.o virtio_ring.o
> 
>  CFLAGS += -g -O2 -Werror -Wno-maybe-uninitialized -Wall -I. -I../include/ -I ../../usr/include/ -Wno-pointer-sign -fno-strict-overflow -fno-strict-aliasing -fno-common -MMD -U_FORTIFY_SOURCE -include ../../include/linux/kconfig.h
> -LDFLAGS += -lpthread
> +LDFLAGS += -pthread
>  vpath %.c ../../drivers/virtio ../../drivers/vhost
>  mod:
>         ${MAKE} -C `pwd`/../.. M=`pwd`/vhost_test V=${V}

gcc documentation seems to say this is neeed in cflags too:

       -pthread
           Define additional macros required for using the POSIX threads library.  You should use this option consistently for both
           compilation and linking.  This option is supported on GNU/Linux targets, most other Unix derivatives, and also on x86
           Cygwin and MinGW targets.

right?

-- 
MST