[Qemu-devel] [RFC PATCH 0/3] vfio/pci: Add support for mmapping sub-page MMIO BARs and MSI-X table

[Yongji Xie]

This patch set adds support for two VFIO-PCI ioctl flags:
VFIO_DEVICE_FLAGS_PCI_PAGE_ALIGNED and VFIO_DEVICE_FLAGS_PCI_MSIX_MMAP.
Note that the kernel bits of this two flags are not in upstream and
posted as <Allow to mmap sub-page MMIO BARs and MSI-X table on
PPC64 platform>.

VFIO_DEVICE_FLAGS_PCI_PAGE_ALIGNED indicates that platform support
all PCI MMIO BARs to be page aligned which means any BARs' mmio
page would not be shared with other BARs. So it's allowed to mmap
sub-page(size < PAGE_SIZE) MMIO BARs in QEMU.

VFIO_DEVICE_FLAGS_PCI_MSIX_MMAP indicates that it's safe to mmap MSI-X
table in QEMU.

Besides supporting for these two mmapping cases, we also fix some issues
which would block KVM to create memory slot for these mmapped sub-page
MMIO BARs and mmapped MSI-X table.

Posted kernel patches link:
- https://www.mail-archive.com/address@hidden/msg124031.html

Yongji Xie (3):
  linux-headers: Update VFIO headers from linux-next tag ToBeFilled
  vfio/pci: Add support for mmapped sub-page MMIO BARs
  vfio/pci: Add support for mmapping MSI-X table

 hw/vfio/pci.c              |   65 ++++++++++++++++++++++++++++++++++++++++----
 linux-headers/linux/vfio.h |    4 +++
 2 files changed, 64 insertions(+), 5 deletions(-)

-- 
1.7.9.5