Add topology description to the virtio-iommu driver and enable x86
platforms. Since the RFC [1] I've mostly given up on ACPI tables, since
the internal discussions seem to have reached a dead end. The built-in
topology description presented here isn't ideal, but it is simple to
implement and doesn't impose a dependency on ACPI or device-tree, which
can be beneficial to lightweight hypervisors.
The built-in description is an array in the virtio config space. The
driver parses the config space early and postpones endpoint probe until
the virtio-iommu device is ready. Each element in the array describes
either a PCI range or a single MMIO endpoint, and their associated
endpoint IDs:
struct virtio_iommu_topo_pci_range {
__le16 type; /* 1: PCI range */
__le16 hierarchy; /* PCI domain number */
__le16 requester_start; /* First BDF */
__le16 requester_end; /* Last BDF */
__le32 endpoint_start; /* First endpoint ID */
};
struct virtio_iommu_topo_endpoint {
__le16 type; /* 2: Endpoint */
__le16 reserved; /* 0 */
__le32 endpoint; /* Endpoint ID */
__le64 address; /* First MMIO address */
};
You can find the QEMU patches based on Eric's latest device on my
virtio-iommu/devel branch [2]. I test on both x86 q35, and aarch64 virt
machine with edk2.
[1]
https://lore.kernel.org/linux-iommu/20191122105000.800410-1-jean-phili...@linaro.org/
[2] https://jpbrucker.net/git/qemu virtio-iommu/devel
Jean-Philippe Brucker (3):
iommu/virtio: Add topology description to virtio-iommu config space
PCI: Add DMA configuration for virtual platforms
iommu/virtio: Enable x86 support
MAINTAINERS | 2 +
drivers/iommu/Kconfig | 13 +-
drivers/iommu/Makefile | 1 +
drivers/iommu/virtio-iommu-topology.c | 343 ++++++++++++++++++++++++++
drivers/iommu/virtio-iommu.c | 3 +
drivers/pci/pci-driver.c | 5 +
include/linux/virt_iommu.h | 19 ++
include/uapi/linux/virtio_iommu.h | 26 ++
8 files changed, 411 insertions(+), 1 deletion(-)
create mode 100644 drivers/iommu/virtio-iommu-topology.c
create mode 100644 include/linux/virt_iommu.h
--
2.25.0
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