virtio: replace restricted mem access flag with callback
Instead of having a global flag to require restricted memory access
for all virtio devices, introduce a callback which can select that
requirement on a per-device basis.
For convenience add a common function returning always true, which can
be used for use cases like SEV.
Per default use a callback always returning false.
As the callback needs to be set in early init code already, add a
virtio anchor which is builtin in case virtio is enabled.
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 guest using Xen
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20220622063838.8854-2-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index e1556d2..56c77f63 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -1,6 +1,10 @@
# SPDX-License-Identifier: GPL-2.0-only
+config VIRTIO_ANCHOR
+ bool
+
config VIRTIO
tristate
+ select VIRTIO_ANCHOR
help
This option is selected by any driver which implements the virtio
bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
