[RFC PATCH 9/9] vfio_pci_core: support mmap attrs uapi & WC

[Mahmoud Adam <mngyadam@amazon.de>]

Now we established the required dependencies to support WC through the
new vmmap in vfio_pci, this implements the new uapi & checks if the WC
attr is set while mmaping, then calls pgprot_writecombine.

Signed-off-by: Mahmoud Adam <mngyadam@amazon.de>
---
 drivers/vfio/pci/vfio_pci_core.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 8418d98ac66ce..461440700af75 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1198,6 +1198,30 @@ static int vfio_pci_ioctl_get_region_info2(struct vfio_pci_core_device *vdev,
 	return _vfio_pci_ioctl_get_region_info(vdev, mmap_mt, arg);
 }
 
+static int vfio_pci_ioctl_set_mmap_attrs(struct vfio_pci_core_device *vdev,
+					 struct maple_tree *mmap_mt,
+					 struct vfio_irq_info __user *arg)
+{
+	struct vfio_mmap_attrs vmmap_attrs;
+	struct vfio_pci_mmap *vmmap;
+
+	if (copy_from_user(&vmmap_attrs, arg, sizeof(vmmap_attrs)))
+		return -EFAULT;
+
+	if (vmmap_attrs.attrs & ~VFIO_MMAP_ATTR_WRITE_COMBINE)
+		return -EINVAL;
+
+	vmmap = mtree_load(mmap_mt, vmmap_attrs.offset);
+	if (!vmmap)
+		return -EINVAL;
+
+	if (!(vmmap->core.region_flags & VFIO_REGION_INFO_FLAG_MMAP))
+		return -EINVAL;
+
+	vmmap->core.attrs = vmmap_attrs.attrs;
+	return 0;
+}
+
 static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
 				       struct vfio_irq_info __user *arg)
 {
@@ -1549,6 +1573,8 @@ long vfio_pci_core_ioctl2(struct vfio_device *core_vdev, unsigned int cmd,
 	switch (cmd) {
 	case VFIO_DEVICE_GET_REGION_INFO:
 		return vfio_pci_ioctl_get_region_info2(vdev, mmap_mt, uarg);
+	case VFIO_DEVICE_SET_MMAP_ATTRS:
+		return vfio_pci_ioctl_set_mmap_attrs(vdev, mmap_mt, uarg);
 	default:
 		return vfio_pci_core_ioctl(core_vdev, cmd, arg);
 	}
@@ -1855,7 +1881,10 @@ static int _vfio_pci_core_mmap(struct vfio_device *core_vdev,
 	}
 
 	vma->vm_private_data = vdev;
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	if (vmmap && vmmap->core.attrs & VFIO_MMAP_ATTR_WRITE_COMBINE)
+		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+	else
+		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
 
 	/*
-- 
2.47.3




Amazon Web Services Development Center Germany GmbH
Tamara-Danz-Str. 13
10243 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B
Sitz: Berlin
Ust-ID: DE 365 538 597