Current vfio-pci implementation disallows to mmap MSI-X table in
case that user get to touch this directly.
However, EEH mechanism could ensure that a given pci device
can only shoot the MSIs assigned for its PE and guest kernel also
would not write to MSI-X table in pci_enable_msix() because
para-virtualization on PPC64 platform. So MSI-X table is safe to
access directly from the guest with EEH mechanism enabled.
This patch adds support for this case and allow to mmap MSI-X
table if EEH is supported on PPC64 platform.
And we also add a VFIO_DEVICE_FLAGS_PCI_MSIX_MMAP flag to notify
userspace that it's safe to mmap MSI-X table.
Signed-off-by: Yongji Xie <xyj...@linux.vnet.ibm.com>
---
drivers/vfio/pci/vfio_pci.c | 5 ++++-
drivers/vfio/pci/vfio_pci_private.h | 5 +++++
include/uapi/linux/vfio.h | 2 ++
3 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index dbcad99..85d9980 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -446,6 +446,9 @@ static long vfio_pci_ioctl(void *device_data,
if (vfio_pci_bar_page_aligned())
info.flags |= VFIO_DEVICE_FLAGS_PCI_PAGE_ALIGNED;
+ if (vfio_msix_table_mmap_enabled())
+ info.flags |= VFIO_DEVICE_FLAGS_PCI_MSIX_MMAP;
+
info.num_regions = VFIO_PCI_NUM_REGIONS;
info.num_irqs = VFIO_PCI_NUM_IRQS;
@@ -871,7 +874,7 @@ static int vfio_pci_mmap(void *device_data, struct
vm_area_struct *vma)
if (phys_len < PAGE_SIZE || req_start + req_len > phys_len)
return -EINVAL;
- if (index == vdev->msix_bar) {
+ if (index == vdev->msix_bar && !vfio_msix_table_mmap_enabled()) {
/*
* Disallow mmaps overlapping the MSI-X table; users don't
* get to touch this directly. We could find somewhere
diff --git a/drivers/vfio/pci/vfio_pci_private.h
b/drivers/vfio/pci/vfio_pci_private.h
index 319352a..835619e 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -74,6 +74,11 @@ static inline bool vfio_pci_bar_page_aligned(void)
return IS_ENABLED(CONFIG_PPC64);
}
+static inline bool vfio_msix_table_mmap_enabled(void)
+{
+ return IS_ENABLED(CONFIG_EEH);
+}
+
extern void vfio_pci_intx_mask(struct vfio_pci_device *vdev);
extern void vfio_pci_intx_unmask(struct vfio_pci_device *vdev);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 1fc8066..289e662 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -173,6 +173,8 @@ struct vfio_device_info {
#define VFIO_DEVICE_FLAGS_AMBA (1 << 3) /* vfio-amba device */
/* Platform support all PCI MMIO BARs to be page aligned */
#define VFIO_DEVICE_FLAGS_PCI_PAGE_ALIGNED (1 << 4)
+/* Platform support mmapping PCI MSI-X vector table */
+#define VFIO_DEVICE_FLAGS_PCI_MSIX_MMAP (1 << 5)
__u32 num_regions; /* Max region index + 1 */
__u32 num_irqs; /* Max IRQ index + 1 */
};
--
1.7.9.5
--
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