[PATCH v4 0/4] VFIO platform reset
alex.williamson at redhat.com
Thu Jun 18 09:17:57 PDT 2015
On Thu, 2015-06-18 at 17:23 +0200, Baptiste Reynal wrote:
> Hello everyone,
> I tested and reviewed the patches, everything's fine for me.
Would you like to provide a Sign-off/Ack/Review tag for the series then?
> I agree to be maintainer of vfio platform drivers, though I don't
> think the volume of patches about VFIO will justify a new mailing
Ok, I'll officially post the patch for MAINTAINERS then. Until someone
complains, we'll continue to use the kvm list. Thanks,
> On Thu, Jun 18, 2015 at 12:31 AM, Alex Williamson
> <alex.williamson at redhat.com> wrote:
> > On Mon, 2015-06-15 at 11:09 +0200, Eric Auger wrote:
> >> In situations where the userspace driver is stopped abnormally and the
> >> VFIO platform device is released, the assigned HW device currently is
> >> left running. As a consequence the HW device might continue issuing IRQs
> >> and performing DMA accesses.
> >> On release, no physical IRQ handler is setup anymore. Also the DMA buffers
> >> are unmapped leading to IOMMU aborts. So there is no serious consequence.
> >> However when assigning that HW device again to another userspace driver,
> >> this latter might face some unexpected IRQs and DMA accesses, which are
> >> the result of the previous assignment.
> >> In virtualization use-case, a VM newly granted with that HW device may be
> >> impacted by the assignment of that device to a previous VM:
> >> - IRQs may be injected very early when booting the new guest, even before
> >> the guest driver has initialized leading to possible driver state
> >> inconsistency.
> >> - DMA accesses may hit the newly mapped VM address space at addresses that
> >> may jeopardize the integrity of the newly installed VM.
> >> Obviously the criticity depends on the assigned HW device.
> >> As opposed to PCI, there is no standard mechanism to reset the platform
> >> device.
> >> This series proposes to implement device specific reset functions in
> >> separate in-kernel vfio reset modules. The vfio-platform driver holds
> >> a whitelist of implemented triplets (compat string, module name,
> >> reset function name). When the vfio-platform driver is probed it identifies
> >> the fellow reset module/function matching the compat string of the
> >> device, if any, and forces the load of this reset module.
> >> A first reset module is provided: the vfio-platform-calxedaxgmac
> >> module which implements a basic reset for the Calxeda xgmac.
> >> The series can be found at
> >> https://git.linaro.org/people/eric.auger/linux.git/shortlog/refs/heads/v4.1-rc8-reset-v4
> >> History:
> >> v3 -> v4:
> >> - fix the commit message of "VFIO: platform: add reset struct and lookup table"
> > Baptiste,
> > Any comments? Should we also add something like this to MAINTAINERS
> > before we go much further?
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index d8afd29..c6bf7f6 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -10545,6 +10545,12 @@ F: drivers/vfio/
> > F: include/linux/vfio.h
> > F: include/uapi/linux/vfio.h
> > +VFIO PLATFORM DRIVER
> > +M: Baptiste Reynal <b.reynal at virtualopensystems.com>
> > +L: kvm at vger.kernel.org
> > +S: Maintained
> > +F: drivers/vfio/platform/
> > +
> > VIDEOBUF2 FRAMEWORK
> > M: Pawel Osciak <pawel at osciak.com>
> > M: Marek Szyprowski <m.szyprowski at samsung.com>
> > I'm not sure what you want to be the primary list, maybe it's time to
> > ask for a vfio list. Thanks,
> > Alex
> >> v2 -> v3:
> >> - remove void module_init/exit functions in calxeda reset module
> >> - remove enum vfio_platform_reset_type
> >> - for reset lookup, use ARRAY_SIZE
> >> - in reset put use symbol_put_addr
> >> v1 -> v2:
> >> - much simplified compared to v1 although principle of external modules is
> >> kept: removed mechanism of dynamic registration of reset functions
> >> - list is replaced by whitelist lookup table
> >> - name of the reset function also stored in the lookup table
> >> - autoload of reset modules
> >> RFC -> PATCH v1:
> >> - solution now based on a lookup list instead of specialized driver
> >> Eric Auger (4):
> >> VFIO: platform: add reset struct and lookup table
> >> VFIO: platform: add reset callback
> >> VFIO: platform: populate the reset function on probe
> >> VFIO: platform: Calxeda xgmac reset module
> >> drivers/vfio/platform/Kconfig | 2 +
> >> drivers/vfio/platform/Makefile | 2 +
> >> drivers/vfio/platform/reset/Kconfig | 7 ++
> >> drivers/vfio/platform/reset/Makefile | 5 ++
> >> .../platform/reset/vfio_platform_calxedaxgmac.c | 86 ++++++++++++++++++++++
> >> drivers/vfio/platform/vfio_platform_common.c | 60 ++++++++++++++-
> >> drivers/vfio/platform/vfio_platform_private.h | 7 ++
> >> 7 files changed, 166 insertions(+), 3 deletions(-)
> >> create mode 100644 drivers/vfio/platform/reset/Kconfig
> >> create mode 100644 drivers/vfio/platform/reset/Makefile
> >> create mode 100644 drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c
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