David Woodhouse
2022-Feb-21 17:18 UTC
[PATCH] tools/virtio: Test virtual address range detection
On Mon, 2022-02-21 at 18:02 +0100, Stefano Garzarella wrote:> On Mon, Feb 21, 2022 at 04:15:22PM +0000, David Woodhouse wrote: > > As things stand, an application which wants to use vhost with a trivial > > 1:1 mapping of its virtual address space is forced to jump through hoops > > to detect what the address range might be. The VHOST_SET_MEM_TABLE ioctl > > helpfully doesn't fail immediately; you only get a failure *later* when > > you attempt to set the backend, if the table *could* map to an address > > which is out of range, even if no out-of-range address is actually > > being referenced. > > > > Since userspace is growing workarounds for this lovely kernel API, let's > > ensure that we have a regression test that does things basically the same > > way as > > https://gitlab.com/openconnect/openconnect/-/commit/443edd9d8826 > > > > does. > > > > This is untested as I can't actually get virtio_test to work at all; it > > just seems to deadlock on a spinlock. But it's getting the right answer > > for the virtio range on x86_64 at least. > > I had a similar issue with virtio_test and this simple patch [1] should > fix the deadlock. > > [1] > https://lore.kernel.org/lkml/20220118150631.167015-1-sgarzare at redhat.com/Thanks. [dwoodhou at 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 In file included from ./linux/uio.h:3, from ./linux/../../../include/linux/vringh.h:15, from ./linux/vringh.h:1, from vringh_test.c:9: ./linux/../../../include/linux/uio.h:10:10: fatal error: linux/mm_types.h: No such file or directory 10 | #include <linux/mm_types.h> | ^~~~~~~~~~~~~~~~~~ compilation terminated. make: *** [<builtin>: vringh_test.o] Error 1 -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/pkcs7-signature Size: 5965 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20220221/fd371089/attachment-0001.p7s>
Michael S. Tsirkin
2022-Feb-22 06:31 UTC
[PATCH] tools/virtio: Test virtual address range detection
On Mon, Feb 21, 2022 at 05:18:48PM +0000, David Woodhouse wrote:> On Mon, 2022-02-21 at 18:02 +0100, Stefano Garzarella wrote: > > On Mon, Feb 21, 2022 at 04:15:22PM +0000, David Woodhouse wrote: > > > As things stand, an application which wants to use vhost with a trivial > > > 1:1 mapping of its virtual address space is forced to jump through hoops > > > to detect what the address range might be. The VHOST_SET_MEM_TABLE ioctl > > > helpfully doesn't fail immediately; you only get a failure *later* when > > > you attempt to set the backend, if the table *could* map to an address > > > which is out of range, even if no out-of-range address is actually > > > being referenced. > > > > > > Since userspace is growing workarounds for this lovely kernel API, let's > > > ensure that we have a regression test that does things basically the same > > > way as > > > https://gitlab.com/openconnect/openconnect/-/commit/443edd9d8826 > > > > > > does. > > > > > > This is untested as I can't actually get virtio_test to work at all; it > > > just seems to deadlock on a spinlock. But it's getting the right answer > > > for the virtio range on x86_64 at least. > > > > I had a similar issue with virtio_test and this simple patch [1] should > > fix the deadlock. > > > > [1] > > https://lore.kernel.org/lkml/20220118150631.167015-1-sgarzare at redhat.com/> > Thanks. > > [dwoodhou at 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 > In file included from ./linux/uio.h:3, > from ./linux/../../../include/linux/vringh.h:15, > from ./linux/vringh.h:1, > from vringh_test.c:9: > ./linux/../../../include/linux/uio.h:10:10: fatal error: linux/mm_types.h: No such file or directory > 10 | #include <linux/mm_types.h> > | ^~~~~~~~~~~~~~~~~~ > compilation terminated. > make: *** [<builtin>: vringh_test.o] Error 1Which tree has this build failure? In mine linux/uio.h does not include linux/mm_types.h. -- MST