Build error in Intel 32-bit hosts

[Aleksandar Markovic]

The code base is on master, checked out on Thursday June25th 2020, 0250c595c9d. The build procedure:

$ mkdir build-gcc
$ cd build-gcc
$ ../configure
$ make

The build error message is:

  CC x86_64-softmmu/hw/hyperv/hyperv.o
  CC x86_64-softmmu/hw/hyperv/hyperv_testdev.o
  CC x86_64-softmmu/hw/hyperv/vmbus.o
/home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c: In function ‘gpadl_iter_io’:
/home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c:386:13: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
         p = (void *)(((uintptr_t)iter->map & TARGET_PAGE_MASK) | off_in_page);
             ^
cc1: all warnings being treated as errors
make[1]: *** [/home/rtrk/Build/qemu-master/rules.mak:69: hw/hyperv/vmbus.o] Error 1
make: *** [Makefile:527: x86_64-softmmu/all] Error 2

[Aleksandar Markovic (aleksandar-markovic)]

пет, 26. јун 2020. у 09:11 Aleksandar Markovic
<email address hidden> је написао/ла:
>
> Public bug reported:
>
> The code base is on master, checked out on Thursday June25th 2020,
> 0250c595c9d. The build procedure:
>
> $ mkdir build-gcc
> $ cd build-gcc
> $ ../configure
> $ make
>
> The build error message is:
>
> CC x86_64-softmmu/hw/hyperv/hyperv.o
> CC x86_64-softmmu/hw/hyperv/hyperv_testdev.o
> CC x86_64-softmmu/hw/hyperv/vmbus.o
> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c: In function ‘gpadl_iter_io’:
> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c:386:13: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
> p = (void *)(((uintptr_t)iter->map & TARGET_PAGE_MASK) | off_in_page);
> ^
> cc1: all warnings being treated as errors
> make[1]: *** [/home/rtrk/Build/qemu-master/rules.mak:69: hw/hyperv/vmbus.o] Error 1
> make: *** [Makefile:527: x86_64-softmmu/all] Error 2
>

Jon,

Do arilyou have any comment or insight on this?

Thanks,
Aleksandar

> ** Affects: qemu
> Importance: Undecided
> Status: New
>
> --
> You received this bug notification because you are a member of qemu-
> devel-ml, which is subscribed to QEMU.
> https://bugs.launchpad.net/bugs/1885247
>
> Title:
> Build error in Intel 32-bit hosts
>
> Status in QEMU:
> New
>
> Bug description:
> The code base is on master, checked out on Thursday June25th 2020,
> 0250c595c9d. The build procedure:
>
> $ mkdir build-gcc
> $ cd build-gcc
> $ ../configure
> $ make
>
> The build error message is:
>
> CC x86_64-softmmu/hw/hyperv/hyperv.o
> CC x86_64-softmmu/hw/hyperv/hyperv_testdev.o
> CC x86_64-softmmu/hw/hyperv/vmbus.o
> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c: In function ‘gpadl_iter_io’:
> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c:386:13: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
> p = (void *)(((uintptr_t)iter->map & TARGET_PAGE_MASK) | off_in_page);
> ^
> cc1: all warnings being treated as errors
> make[1]: *** [/home/rtrk/Build/qemu-master/rules.mak:69: hw/hyperv/vmbus.o] Error 1
> make: *** [Makefile:527: x86_64-softmmu/all] Error 2
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/qemu/+bug/1885247/+subscriptions
>

[Peter Maydell (pmaydell)]

I suspect an extra uintptr_t cast will fix this:

p = (void *)(uintptr_t)(((uintptr_t)iter->map & TARGET_PAGE_MASK) | off_in_page);

Which looks kind of ugly but then the code is taking a host void* (iter->map), casting it to integer to do arithmetic on and then wanting to get it back to a void* which is inherently going to result in a mess of casting...

[Philippe Mathieu-Daudé (philmd)]

On 6/26/20 9:37 AM, Aleksandar Markovic wrote:
> пет, 26. јун 2020. у 09:11 Aleksandar Markovic
> <email address hidden> је написао/ла:
>>
>> Public bug reported:
>>
>> The code base is on master, checked out on Thursday June25th 2020,
>> 0250c595c9d. The build procedure:
>>
>> $ mkdir build-gcc
>> $ cd build-gcc
>> $ ../configure
>> $ make
>>
>> The build error message is:
>>
>> CC x86_64-softmmu/hw/hyperv/hyperv.o
>> CC x86_64-softmmu/hw/hyperv/hyperv_testdev.o
>> CC x86_64-softmmu/hw/hyperv/vmbus.o
>> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c: In function ‘gpadl_iter_io’:
>> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c:386:13: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>> p = (void *)(((uintptr_t)iter->map & TARGET_PAGE_MASK) | off_in_page);
>> ^
>> cc1: all warnings being treated as errors
>> make[1]: *** [/home/rtrk/Build/qemu-master/rules.mak:69: hw/hyperv/vmbus.o] Error 1
>> make: *** [Makefile:527: x86_64-softmmu/all] Error 2

FWIW there is no CI job covering x86 KVM on 32-bit host build.
Should this be covered? I guess the problem is no CI services
provide 32-bit x86...

[Philippe Mathieu-Daudé (philmd)]

On 6/26/20 11:20 AM, Thomas Huth wrote:
> On 26/06/2020 11.13, Philippe Mathieu-Daudé wrote:
>> On 6/26/20 9:37 AM, Aleksandar Markovic wrote:
>>> пет, 26. јун 2020. у 09:11 Aleksandar Markovic
>>> <email address hidden> је написао/ла:
>>>>
>>>> Public bug reported:
>>>>
>>>> The code base is on master, checked out on Thursday June25th 2020,
>>>> 0250c595c9d. The build procedure:
>>>>
>>>> $ mkdir build-gcc
>>>> $ cd build-gcc
>>>> $ ../configure
>>>> $ make
>>>>
>>>> The build error message is:
>>>>
>>>>    CC      x86_64-softmmu/hw/hyperv/hyperv.o
>>>>    CC      x86_64-softmmu/hw/hyperv/hyperv_testdev.o
>>>>    CC      x86_64-softmmu/hw/hyperv/vmbus.o
>>>> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c: In function
>>>> ‘gpadl_iter_io’:
>>>> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c:386:13: error: cast
>>>> to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>>>           p = (void *)(((uintptr_t)iter->map & TARGET_PAGE_MASK) |
>>>> off_in_page);
>>>>               ^
>>>> cc1: all warnings being treated as errors
>>>> make[1]: *** [/home/rtrk/Build/qemu-master/rules.mak:69:
>>>> hw/hyperv/vmbus.o] Error 1
>>>> make: *** [Makefile:527: x86_64-softmmu/all] Error 2
>>
>> FWIW there is no CI job covering x86 KVM on 32-bit host build.
>> Should this be covered? I guess the problem is no CI services
>> provide 32-bit x86...
>
> You can certainly provide either a container, or install the 32-bit
> libraries in a 64-bit environment. Then run
>
> PKG_CONFIG_LIBDIR=... ./configure --extra-cflags=-m32
>
> and it should be possible to build 32-bit binaries, too.
>
> Alternatively, we could add a cross-compilation job that builds with
> i686-w64-mingw32 in 32-bit.

Oh, this case is covered:
https://app.shippable.com/github/qemu/qemu/runs/2437/2/console

But this doesn't use KVM ;)

[Aleksandar Markovic (aleksandar-markovic)]

пет, 26. јун 2020. у 12:54 Jon Doron <email address hidden> је написао/ла:
>
> Is there a container I can download which has your build environment?
>

Hello, Jon.

I don't know about the container, but, as Peter noted, the following
(non-beautiful) diff fixes the build problem on the real host:

diff --git a/hw/hyperv/vmbus.c b/hw/hyperv/vmbus.c
index f371240176..9220f7b529 100644
--- a/hw/hyperv/vmbus.c
+++ b/hw/hyperv/vmbus.c
@@ -383,7 +383,8 @@ static ssize_t gpadl_iter_io(GpadlIter *iter, void
*buf, uint32_t len)
             }
         }

- p = (void *)(((uintptr_t)iter->map & TARGET_PAGE_MASK) | off_in_page);
+ p = (void *)(uintptr_t)(((uintptr_t)iter->map & TARGET_PAGE_MASK) |
+ off_in_page);
         if (iter->dir == DMA_DIRECTION_FROM_DEVICE) {
             memcpy(p, buf, cplen);
         } else {

Not sure if this is an optimal/most-elegant solution though.

Warmly,
Aleksandar

> On Fri, Jun 26, 2020 at 12:27 PM Philippe Mathieu-Daudé
> <email address hidden> wrote:
> >
> > On 6/26/20 11:20 AM, Thomas Huth wrote:
> > > On 26/06/2020 11.13, Philippe Mathieu-Daudé wrote:
> > >> On 6/26/20 9:37 AM, Aleksandar Markovic wrote:
> > >>> пет, 26. јун 2020. у 09:11 Aleksandar Markovic
> > >>> <email address hidden> је написао/ла:
> > >>>>
> > >>>> Public bug reported:
> > >>>>
> > >>>> The code base is on master, checked out on Thursday June25th 2020,
> > >>>> 0250c595c9d. The build procedure:
> > >>>>
> > >>>> $ mkdir build-gcc
> > >>>> $ cd build-gcc
> > >>>> $ ../configure
> > >>>> $ make
> > >>>>
> > >>>> The build error message is:
> > >>>>
> > >>>> CC x86_64-softmmu/hw/hyperv/hyperv.o
> > >>>> CC x86_64-softmmu/hw/hyperv/hyperv_testdev.o
> > >>>> CC x86_64-softmmu/hw/hyperv/vmbus.o
> > >>>> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c: In function
> > >>>> ‘gpadl_iter_io’:
> > >>>> /home/rtrk/Build/qemu-master/hw/hyperv/vmbus.c:386:13: error: cast
> > >>>> to pointer from integer of different size [-Werror=int-to-pointer-cast]
> > >>>> p = (void *)(((uintptr_t)iter->map & TARGET_PAGE_MASK) |
> > >>>> off_in_page);
> > >>>> ^
> > >>>> cc1: all warnings being treated as errors
> > >>>> make[1]: *** [/home/rtrk/Build/qemu-master/rules.mak:69:
> > >>>> hw/hyperv/vmbus.o] Error 1
> > >>>> make: *** [Makefile:527: x86_64-softmmu/all] Error 2
> > >>
> > >> FWIW there is no CI job covering x86 KVM on 32-bit host build.
> > >> Should this be covered? I guess the problem is no CI services
> > >> provide 32-bit x86...
> > >
> > > You can certainly provide either a container, or install the 32-bit
> > > libraries in a 64-bit environment. Then run
> > >
> > > PKG_CONFIG_LIBDIR=... ./configure --extra-cflags=-m32
> > >
> > > and it should be possible to build 32-bit binaries, too.
> > >
> > > Alternatively, we could add a cross-compilation job that builds with
> > > i686-w64-mingw32 in 32-bit.
> >
> > Oh, this case is covered:
> > https://app.shippable.com/github/qemu/qemu/runs/2437/2/console
> >
> > But this doesn't use KVM ;)
> >

[Thomas Huth (th-huth)]

Fix had been included here:
https://gitlab.com/qemu-project/qemu/-/commit/8b39aa90e90
... thus closing this ticket now.