| Message ID | edb2ec654fc27ba8f73695382ab0a029f18422b5.1754311439.git.leon@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | vfio/pci: Allow MMIO regions to be exported through dma-buf | expand |
On Mon, 4 Aug 2025 16:00:43 +0300 Leon Romanovsky <leon@kernel.org> wrote: > From: Leon Romanovsky <leonro@nvidia.com> > > Make sure that all VFIO PCI devices have peer-to-peer capabilities > enables, so we would be able to export their MMIO memory through DMABUF, > > Signed-off-by: Leon Romanovsky <leonro@nvidia.com> > --- > drivers/vfio/pci/vfio_pci_core.c | 4 ++++ > include/linux/vfio_pci_core.h | 1 + > 2 files changed, 5 insertions(+) > > diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c > index 31bdb9110cc0f..df9a32d3deac9 100644 > --- a/drivers/vfio/pci/vfio_pci_core.c > +++ b/drivers/vfio/pci/vfio_pci_core.c > @@ -28,6 +28,7 @@ > #include <linux/nospec.h> > #include <linux/sched/mm.h> > #include <linux/iommufd.h> > +#include <linux/pci-p2pdma.h> > #if IS_ENABLED(CONFIG_EEH) > #include <asm/eeh.h> > #endif > @@ -2088,6 +2089,9 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev) > INIT_LIST_HEAD(&vdev->dummy_resources_list); > INIT_LIST_HEAD(&vdev->ioeventfds_list); > INIT_LIST_HEAD(&vdev->sriov_pfs_item); > + vdev->provider = pci_p2pdma_enable(vdev->pdev); > + if (IS_ERR(vdev->provider)) > + return PTR_ERR(vdev->provider); I think this just made all vfio-pci drivers functionally dependent on CONFIG_PCI_P2PDMA. Seems at best exporting a dma-buf should be restricted if this fails. Thanks, Alex > init_rwsem(&vdev->memory_lock); > xa_init(&vdev->ctx); > > diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h > index fbb472dd99b36..b017fae251811 100644 > --- a/include/linux/vfio_pci_core.h > +++ b/include/linux/vfio_pci_core.h > @@ -94,6 +94,7 @@ struct vfio_pci_core_device { > struct vfio_pci_core_device *sriov_pf_core_dev; > struct notifier_block nb; > struct rw_semaphore memory_lock; > + struct p2pdma_provider *provider; > }; > > /* Will be exported for vfio pci drivers usage */
On Wed, Aug 06, 2025 at 04:02:01PM -0600, Alex Williamson wrote: > On Mon, 4 Aug 2025 16:00:43 +0300 > Leon Romanovsky <leon@kernel.org> wrote: > > > From: Leon Romanovsky <leonro@nvidia.com> > > > > Make sure that all VFIO PCI devices have peer-to-peer capabilities > > enables, so we would be able to export their MMIO memory through DMABUF, > > > > Signed-off-by: Leon Romanovsky <leonro@nvidia.com> > > --- > > drivers/vfio/pci/vfio_pci_core.c | 4 ++++ > > include/linux/vfio_pci_core.h | 1 + > > 2 files changed, 5 insertions(+) > > > > diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c > > index 31bdb9110cc0f..df9a32d3deac9 100644 > > --- a/drivers/vfio/pci/vfio_pci_core.c > > +++ b/drivers/vfio/pci/vfio_pci_core.c > > @@ -28,6 +28,7 @@ > > #include <linux/nospec.h> > > #include <linux/sched/mm.h> > > #include <linux/iommufd.h> > > +#include <linux/pci-p2pdma.h> > > #if IS_ENABLED(CONFIG_EEH) > > #include <asm/eeh.h> > > #endif > > @@ -2088,6 +2089,9 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev) > > INIT_LIST_HEAD(&vdev->dummy_resources_list); > > INIT_LIST_HEAD(&vdev->ioeventfds_list); > > INIT_LIST_HEAD(&vdev->sriov_pfs_item); > > + vdev->provider = pci_p2pdma_enable(vdev->pdev); > > + if (IS_ERR(vdev->provider)) > > + return PTR_ERR(vdev->provider); > > I think this just made all vfio-pci drivers functionally dependent on > CONFIG_PCI_P2PDMA. Seems at best exporting a dma-buf should be > restricted if this fails. Thanks, It is temporary solution in next patch "vfio/pci: Add dma-buf export support for MMIO regions", the strict ifdef is added. 2107 #ifdef CONFIG_VFIO_PCI_DMABUF 2108 vdev->provider = pci_p2pdma_enable(vdev->pdev); 2109 if (IS_ERR(vdev->provider)) 2110 return PTR_ERR(vdev->provider); 2111 2112 INIT_LIST_HEAD(&vdev->dmabufs); 2113 #endif I will split "vfio/pci: Add dma-buf export ..." patch to introduce CONFIG_VFIO_PCI_DMABUF before this "vfio/pci: Enable peer-to-peer ..." patch. Thanks > > Alex > > > init_rwsem(&vdev->memory_lock); > > xa_init(&vdev->ctx); > > > > diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h > > index fbb472dd99b36..b017fae251811 100644 > > --- a/include/linux/vfio_pci_core.h > > +++ b/include/linux/vfio_pci_core.h > > @@ -94,6 +94,7 @@ struct vfio_pci_core_device { > > struct vfio_pci_core_device *sriov_pf_core_dev; > > struct notifier_block nb; > > struct rw_semaphore memory_lock; > > + struct p2pdma_provider *provider; > > }; > > > > /* Will be exported for vfio pci drivers usage */ >
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 31bdb9110cc0f..df9a32d3deac9 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -28,6 +28,7 @@ #include <linux/nospec.h> #include <linux/sched/mm.h> #include <linux/iommufd.h> +#include <linux/pci-p2pdma.h> #if IS_ENABLED(CONFIG_EEH) #include <asm/eeh.h> #endif @@ -2088,6 +2089,9 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev) INIT_LIST_HEAD(&vdev->dummy_resources_list); INIT_LIST_HEAD(&vdev->ioeventfds_list); INIT_LIST_HEAD(&vdev->sriov_pfs_item); + vdev->provider = pci_p2pdma_enable(vdev->pdev); + if (IS_ERR(vdev->provider)) + return PTR_ERR(vdev->provider); init_rwsem(&vdev->memory_lock); xa_init(&vdev->ctx); diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index fbb472dd99b36..b017fae251811 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -94,6 +94,7 @@ struct vfio_pci_core_device { struct vfio_pci_core_device *sriov_pf_core_dev; struct notifier_block nb; struct rw_semaphore memory_lock; + struct p2pdma_provider *provider; }; /* Will be exported for vfio pci drivers usage */