On Sun, 28 Sep 2025 17:50:17 +0300 Leon Romanovsky <[email protected]> wrote:
> From: Leon Romanovsky <[email protected]> > > Add new kernel config which indicates support for dma-buf export > of MMIO regions, which implementation is provided in next patches. > > Signed-off-by: Leon Romanovsky <[email protected]> > --- > drivers/vfio/pci/Kconfig | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig > index 2b0172f54665..55ae888bf26a 100644 > --- a/drivers/vfio/pci/Kconfig > +++ b/drivers/vfio/pci/Kconfig > @@ -55,6 +55,26 @@ config VFIO_PCI_ZDEV_KVM > > To enable s390x KVM vfio-pci extensions, say Y. > > +config VFIO_PCI_DMABUF > + bool "VFIO PCI extensions for DMA-BUF" > + depends on VFIO_PCI_CORE > + depends on PCI_P2PDMA && DMA_SHARED_BUFFER > + default y > + help > + Enable support for VFIO PCI extensions that allow exporting > + device MMIO regions as DMA-BUFs for peer devices to access via > + peer-to-peer (P2P) DMA. > + > + This feature enables a VFIO-managed PCI device to export a portion > + of its MMIO BAR as a DMA-BUF file descriptor, which can be passed > + to other userspace drivers or kernel subsystems capable of > + initiating DMA to that region. > + > + Say Y here if you want to enable VFIO DMABUF-based MMIO export > + support for peer-to-peer DMA use cases. > + > + If unsure, say N. > + > source "drivers/vfio/pci/mlx5/Kconfig" > > source "drivers/vfio/pci/hisilicon/Kconfig" This is only necessary if we think there's a need to build a kernel with P2PDMA and VFIO_PCI, but not VFIO_PCI_DMABUF. Does that need really exist? I also find it unusual to create the Kconfig before adding the supporting code. Maybe this could be popped to the end or rolled into the last patch if we decided to keep it. Thanks, Alex
