[PATCH 4.14 128/242] vfio-pci: Use io_remap_pfn_range() for PCI IO memory

Greg Kroah-Hartman
2020-12-28T16:20:51Z

From: Jason Gunthorpe <jgg@nvidia.com>

[ Upstream commit 7b06a56d468b756ad6bb43ac21b11e474ebc54a0 ]

commit f8f6ae5d077a ("mm: always have io_remap_pfn_range() set
pgprot_decrypted()") allows drivers using mmap to put PCI memory mapped
BAR space into userspace to work correctly on AMD SME systems that default
to all memory encrypted.

Since vfio_pci_mmap_fault() is working with PCI memory mapped BAR space it
should be calling io_remap_pfn_range() otherwise it will not work on SME
systems.

Fixes: 11c4cd07ba11 ("vfio-pci: Fault mmaps to enable vma tracking")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Peter Xu <peterx@redhat.com>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/vfio/pci/vfio_pci.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index ac1c54bcfe8fb..6fceefcab81db 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1380,8 +1380,8 @@ static int vfio_pci_mmap_fault(struct vm_fault *vmf)

mutex_unlock(&vdev->vma_lock);

- if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
- vma->vm_end - vma->vm_start, vma->vm_page_prot))
+ if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
+ vma->vm_end - vma->vm_start, vma->vm_page_prot))
ret = VM_FAULT_SIGBUS;

up_out:
--
2.27.0