Messages in this thread | | | Subject | Re: [RFC PATCH 0/3] VFIO: capability chains | From | Alexey Kardashevskiy <> | Date | Fri, 18 Dec 2015 13:05:49 +1100 |
| |
On 11/24/2015 07:43 AM, Alex Williamson wrote: > Please see the commit log and comments in patch 1 for a general > explanation of the problems that this series tries to address. The > general problem is that we have several cases where we want to expose > variable sized information to the user, whether it's sparse mmaps for > a region, as implemented here, or DMA mapping ranges of an IOMMU, or > reserved MSI mapping ranges, etc. Extending data structures is hard; > extending them to report variable sized data is really hard. After > considering several options, I think the best approach is to copy how > PCI does capabilities. This allows the ioctl to only expose the > capabilities that are relevant for them, avoids data structures that > are too complicated to parse, and avoids creating a new ioctl each > time we think of something else that we'd like to report. This method > also doesn't preclude extensions to the fixed structure since the > offset of these capabilities is entirely dynamic. > > Comments welcome, I'll also follow-up to the QEMU and KVM lists with > an RFC making use of this for mmaps skipping over the MSI-X table. > Thanks,
Out of curiosity - could this information be exposed to the userspace via /sys/bus/pci/devices/xxxx:xx:xx:x/vfio_xxxx? It seems not to change after vfio_pci driver is bound to a device.
> Alex > > --- > > Alex Williamson (3): > vfio: Define capability chains > vfio: Define sparse mmap capability for regions > vfio/pci: Include sparse mmap capability for MSI-X table regions > > > drivers/vfio/pci/vfio_pci.c | 101 +++++++++++++++++++++++++++++++++++++++++++ > include/uapi/linux/vfio.h | 53 ++++++++++++++++++++++- > 2 files changed, 152 insertions(+), 2 deletions(-) > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
-- Alexey
| |