[PATCH v4 3/3] vfio: convey kvm that the vfio-pci device is wc safe

ankita
2023-12-18T09:08:18Z

The code to map the MMIO in S2 as NormalNC is enabled when conveyed
that the device is WC safe using a new flag VM_VFIO_ALLOW_WC.

Make vfio-pci set the VM_VFIO_ALLOW_WC flag.

Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Ankit Agrawal <ankita@nvidia.com>
---
drivers/vfio/pci/vfio_pci_core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 1cbc990d42e0..c3f95ec7fc3a 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1863,7 +1863,8 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
* See remap_pfn_range(), called from vfio_pci_fault() but we can't
* change vm_flags within the fault handler. Set them now.
*/
- vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
+ vm_flags_set(vma, VM_VFIO_ALLOW_WC | VM_IO | VM_PFNMAP |
+ VM_DONTEXPAND | VM_DONTDUMP);
vma->vm_ops = &vfio_pci_mmap_ops;

return 0;
--
2.17.1