| Message ID | 20240523-vfio_pci_mmap-v2-3-0dc6c139a4f1@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfio/pci: s390: Fix issues preventing VFIO_PCI_MMAP=y for s390 and enable it | expand |
On Thu, May 23, 2024 at 01:10:16PM +0200, Niklas Schnelle wrote: > With the introduction of memory I/O (MIO) instructions enbaled in commit > 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") s390 > gained support for direct user-space access to mapped PCI resources. > Even without those however user-space can access mapped PCI resources > via the s390 specific MMIO syscalls. Thus mmap() can and should be > supported on all s390 systems with native PCI. Since VFIO_PCI_MMAP > enablement for s390 would make it unconditionally true and thus > pointless just remove it entirely. > > Link: https://lore.kernel.org/all/c5ba134a1d4f4465b5956027e6a4ea6f6beff969.camel@linux.ibm.com/ > Suggested-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> > --- > drivers/vfio/pci/Kconfig | 4 ---- > drivers/vfio/pci/vfio_pci_core.c | 3 --- > 2 files changed, 7 deletions(-) Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Jason
On 5/23/24 7:10 AM, Niklas Schnelle wrote: > With the introduction of memory I/O (MIO) instructions enbaled in commit > 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") s390 > gained support for direct user-space access to mapped PCI resources. > Even without those however user-space can access mapped PCI resources > via the s390 specific MMIO syscalls. Thus mmap() can and should be > supported on all s390 systems with native PCI. Since VFIO_PCI_MMAP > enablement for s390 would make it unconditionally true and thus > pointless just remove it entirely. > > Link: https://lore.kernel.org/all/c5ba134a1d4f4465b5956027e6a4ea6f6beff969.camel@linux.ibm.com/ > Suggested-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Also sanity tested on s390 with mlx, nvme, ISM over vfio-pci (the latter of which triggers the patch 2 scenario).
diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig index 15821a2d77d2..9c88e3a6d06b 100644 --- a/drivers/vfio/pci/Kconfig +++ b/drivers/vfio/pci/Kconfig @@ -7,10 +7,6 @@ config VFIO_PCI_CORE select VFIO_VIRQFD select IRQ_BYPASS_MANAGER -config VFIO_PCI_MMAP - def_bool y if !S390 - depends on VFIO_PCI_CORE - config VFIO_PCI_INTX def_bool y if !S390 depends on VFIO_PCI_CORE diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 23961299b695..35b8e8f214af 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -121,9 +121,6 @@ static void vfio_pci_probe_mmaps(struct vfio_pci_core_device *vdev) res = &vdev->pdev->resource[bar]; - if (!IS_ENABLED(CONFIG_VFIO_PCI_MMAP)) - goto no_mmap; - if (!(res->flags & IORESOURCE_MEM)) goto no_mmap;
With the introduction of memory I/O (MIO) instructions enbaled in commit 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") s390 gained support for direct user-space access to mapped PCI resources. Even without those however user-space can access mapped PCI resources via the s390 specific MMIO syscalls. Thus mmap() can and should be supported on all s390 systems with native PCI. Since VFIO_PCI_MMAP enablement for s390 would make it unconditionally true and thus pointless just remove it entirely. Link: https://lore.kernel.org/all/c5ba134a1d4f4465b5956027e6a4ea6f6beff969.camel@linux.ibm.com/ Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> --- drivers/vfio/pci/Kconfig | 4 ---- drivers/vfio/pci/vfio_pci_core.c | 3 --- 2 files changed, 7 deletions(-)