Add two functions to print an error/warning report once depending
on a passed-in condition variable and flip it if printed. This is
useful if you want to print a message not once-globally, but e.g.
once-per-device.
Inspired by warn_once() in hw/vfio/ccw.c, which has been replaced
with warn_report_once_cond().
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20180830145902.27376-2-cohuck@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Function comments reworded]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
If a vfio assigned device makes use of a physical IOMMU, then memory
ballooning is necessarily inhibited due to the page pinning, lack of
page level granularity at the IOMMU, and sufficient notifiers to both
remove the page on balloon inflation and add it back on deflation.
However, not all devices are backed by a physical IOMMU. In the case
of mediated devices, if a vendor driver is well synchronized with the
guest driver, such that only pages actively used by the guest driver
are pinned by the host mdev vendor driver, then there should be no
overlap between pages available for the balloon driver and pages
actively in use by the device. Under these conditions, ballooning
should be safe.
vfio-ccw devices are always mediated devices and always operate under
the constraints above. Therefore we can consider all vfio-ccw devices
as balloon compatible.
The situation is far from straightforward with vfio-pci. These
devices can be physical devices with physical IOMMU backing or
mediated devices where it is unknown whether a physical IOMMU is in
use or whether the vendor driver is well synchronized to the working
set of the guest driver. The safest approach is therefore to assume
all vfio-pci devices are incompatible with ballooning, but allow user
opt-in should they have further insight into mediated devices.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
There is at least one guest (OS) such that although it does not rely on
the guarantees provided by ORB 1 word 9 bit (aka unlimited prefetch, aka
P bit) not being set, it fails to tell this to the machine.
Usually this ain't a big deal, as the original purpose of the P bit is to
allow for performance optimizations. vfio-ccw however can not provide the
guarantees required if the bit is not set.
It is not possible to implement support for the P bit not set without
transitioning to lower level protocols for vfio-ccw. So let's give the
user the opportunity to force setting the P bit, if the user knows this
is safe. For self modifying channel programs forcing the P bit is not
safe. If the P bit is forced for a self modifying channel program things
are expected to break in strange ways.
Let's also avoid warning multiple about P bit not set in the ORB in case
P bit is not told to be forced, and designate the affected vfio-ccw
device.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Suggested-by: Dong Jia Shi <bjsdjshi@linux.ibm.com>
Acked-by: Jason J. Herne <jjherne@linux.ibm.com>
Tested-by: Jason J. Herne <jjherne@linux.ibm.com>
Message-Id: <20180524175828.3143-2-pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
No declaration of "hw/vfio/vfio-common.h" directly requires to include
the "exec/address-spaces.h" header. To simplify dependencies and
ease the upcoming cleanup of "exec/address-spaces.h", directly include
it in the source file where the declaration are used.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180528232719.4721-2-f4bug@amsat.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A recent patch fixed leaks of the dynamically allocated vcdev->vdev.name
field in vfio_ccw_realize(), but we now have three freeing sites for it.
This is unfortunate and seems to indicate something is wrong with its
life cycle.
The root issue is that vcdev->vdev.name is set before vfio_get_device()
is called, which theoretically prevents to call vfio_put_device() to
do the freeing. Well actually, we could call it anyway because
vfio_put_base_device() is a nop if the device isn't attached, but this
would be confusing.
This patch hence moves all the logic of attaching the device, including
the "already attached" check, to a separate vfio_ccw_get_device() function,
counterpart of vfio_put_device(). While here, vfio_put_device() is renamed
to vfio_ccw_put_device() for consistency.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <152326891065.266543.9487977590811413472.stgit@bahia.lan>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
If the subchannel is already attached or if vfio_get_device() fails, the
code jumps to the 'out_device_err' label and doesn't free the string it
has just allocated.
The code should be reworked so that vcdev->vdev.name only gets set when
the device has been attached, and freed when it is about to be detached.
This could be achieved with the addition of a vfio_ccw_get_device()
function that would be the counterpart of vfio_put_device(). But this is
a more elaborate cleanup that should be done in a follow-up. For now,
let's just add calls to g_free() on the buggy error paths.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <152311222681.203086.8874800175539040298.stgit@bahia>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Simplify the error handling of the SSCH and RSCH handler avoiding
arbitrary and cryptic error codes being used to tell how the instruction
is supposed to end. Let the code detecting the condition tell how it's
to be handled in a less ambiguous way. It's best to handle SSCH and RSCH
in one go as the emulation of the two shares a lot of code.
For passthrough this change isn't pure refactoring, but changes the way
kernel reported EFAULT is handled. After clarifying the kernel interface
we decided that EFAULT shall be mapped to unit exception. Same goes for
unexpected error codes and absence of required ORB flags.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Message-Id: <20171017140453.51099-4-pasic@linux.vnet.ibm.com>
Tested-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
[CH: cosmetic changes]
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
