um: virt-pci: fix platform map offset

The offset is currently always zero so the backend can't distinguish
between accesses to different ioremapped areas.

Fixes: 522c532c4fe7 ("virt-pci: add platform bus support")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virt-pci: fix missing declaration warning

Fix this warning which appears with W=1 and without CONFIG_OF:

warning: no previous declaration for 'pcibios_get_phb_of_node'

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308230949.PphIIlhq-lkp@intel.com/
Fixes: 314a1408b79a ("um: virt-pci: implement pcibios_get_phb_of_node()")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virt-pci: properly remove PCI device from bus

Triggering a bus rescan will not cause the PCI device to be removed. It
is required to explicitly stop and remove the device from the bus.

Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virtio_uml: free command if adding to virtqueue failed

If adding the command fails (i.e. the virtqueue is broken) then free it
again if the function allocated a new buffer for it.

Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

virt-pci: add platform bus support

This driver registers PCI busses, but the underlying virtio protocol
could just as easily be used to provide a platform bus instead. If the
virtio device node in the devicetree indicates that it's compatible with
simple-bus, register platform devices instead of handling it as a PCI
bus.

Only one platform bus is allowed and the logic MMIO region for the
platform bus is placed at an arbitrarily-chosen address away from the
PCI region.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um-virt-pci: Make max delay configurable

There is a hard coded maximum time for which the driver busy-loops
waiting for a response from the virtio device. This default time may be
too short for some systems, so make it a module parameter so that it can
be set via the kernel command line.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virt-pci: implement pcibios_get_phb_of_node()

Implement pcibios_get_phb_of_node() as x86 does in order to allow PCI
busses to be associated with devicetree nodes.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virt-pci: Avoid GCC non-NULL warning

GCC gets confused about the return value of get_cpu_var() possibly
being NULL, so explicitly test for it before calls to memcpy() and
memset(). Avoids warnings like this:

arch/um/drivers/virt-pci.c: In function 'um_pci_send_cmd':
include/linux/fortify-string.h:48:33: warning: argument 1 null where non-null expected [-Wnonnull]
48 | #define __underlying_memcpy __builtin_memcpy
| ^
include/linux/fortify-string.h:438:9: note: in expansion of macro '__underlying_memcpy'
438 | __underlying_##op(p, q, __fortify_size); \
| ^~~~~~~~~~~~~
include/linux/fortify-string.h:483:26: note: in expansion of macro '__fortify_memcpy_chk'
483 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \
| ^~~~~~~~~~~~~~~~~~~~
arch/um/drivers/virt-pci.c:100:9: note: in expansion of macro 'memcpy'
100 | memcpy(buf, cmd, cmd_size);
| ^~~~~~

While at it, avoid literal "8" and use stored sizeof(buf->data) in
memset() and um_pci_send_cmd().

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/202211271212.SUZSC9f9-lkp@intel.com
Fixes: ba38961a069b ("um: Enable FORTIFY_SOURCE")
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: linux-um@lists.infradead.org
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

um: virt-pci: add __init/__exit annotations to module init/exit funcs

Add missing __init/__exit annotations to module init/exit funcs.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virt-pci: set device ready in probe()

Call virtio_device_ready() to make this driver work after commit
b4ec69d7e09 ("virtio: harden vring IRQ"), since the driver uses the
virtqueues in the probe function. (The virtio core sets the device
ready when probe returns.)

Fixes: 8b4ec69d7e09 ("virtio: harden vring IRQ")
Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Message-Id: <20220610151203.3492541-1-vincent.whitchurch@axis.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Johannes Berg <johannes@sipsolutions.net>

virtio: wrap config->reset calls

This will enable cleanups down the road.
The idea is to disable cbs, then add "flush_queued_cbs" callback
as a parameter, this way drivers can flush any work
queued after callbacks have been disabled.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

um: virt-pci: Fix 32-bit compile

There were a few 32-bit compile warnings that of course
turned into errors with -Werror, fix the 32-bit build.

Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virt-pci: don't do DMA from stack

When enabling VMAP_STACK, SG helpers immediately complained
that we were doing DMA from stack. Use per-CPU variables to
avoid that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: make PCI emulation driver init/exit static

The functions aren't used elsewhere, so they can be static.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: virtio/pci: enable suspend/resume

The UM virtual PCI devices currently cannot be suspended properly
since the virtio driver already disables VQs well before the PCI
bus's suspend_noirq wants to complete the transition by writing to
PCI config space.

After trying around for a long time with moving the devices on the
DPM list, trying to create dependencies between them, etc. I gave
up and instead added UML specific cross-driver API that lets the
virt-pci code enable not suspending/resuming VQs for its devices.

This then allows the PCI bus suspend_noirq to still talk to the
device, and suspend/resume works properly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

um: add PCI over virtio emulation driver

To support testing of PCI/PCIe drivers in UML, add a PCI bus
support driver. This driver uses virtio, which in UML is really
just vhost-user, to talk to devices, and adds the devices to
the virtual PCI bus in the system.

Since virtio already allows DMA/bus mastering this really isn't
all that hard, of course we need the logic_iomem infrastructure
that was added by a previous patch.

The protocol to talk to the device is has a few fairly simple
messages for reading to/writing from config and IO spaces, and
messages for the device to send the various interrupts (INT#,
MSI/MSI-X and while suspended PME#).

Note that currently no offical virtio device ID is assigned for
this protocol, as a consequence this patch requires defining it
in the Kconfig, with a default that makes the driver refuse to
work at all.

Finally, in order to add support for MSI/MSI-X interrupts, some
small changes are needed in the UML IRQ code, it needs to have
more interrupts, changing NR_IRQS from 64 to 128 if this driver
is enabled, but not actually use them for anything so that the
generic IRQ domain/MSI infrastructure can allocate IRQ numbers.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>