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Add page-selective IOTLB flush using HVCALL_FLUSH_DEVICE_DOMAIN_LIST.
This hypercall accepts a list of (page_number, page_mask_shift) entries,
enabling finer-grained IOTLB invalidation compared to the domain-wide
HVCALL_FLUSH_DEVICE_DOMAIN used by hv_iommu_flush_iotlb_all().
hv_iommu_calc_flush_range() computes the smallest power-of-two aligned
range that covers the target IOVA region, producing a single flush
descriptor. This may over-flush when the range is not naturally aligned,
matching the approach used by Intel VT-d PSI. If the page-selective
flush fails, the code falls back to a full domain flush.
Signed-off-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Signed-off-by: Yu Zhang <zhangyu1@linux.microsoft.com>
Reviewed-by: Jacob Pan <jacob.pan@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
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Add a para-virtualized IOMMU driver for Linux guests running on Hyper-V.
This driver implements stage-1 IO translation within the guest OS.
It integrates with the Linux IOMMU core, utilizing Hyper-V hypercalls
for:
- Capability discovery
- Domain allocation, configuration, and deallocation
- Device attachment and detachment
- IOTLB invalidation
The driver constructs x86-compatible stage-1 IO page tables in the
guest memory using consolidated IO page table helpers. This allows
the guest to manage stage-1 translations independently of vendor-
specific drivers (like Intel VT-d or AMD IOMMU).
Hyper-V consumes this stage-1 IO page table when a device domain is
created and configured, and nests it with the host's stage-2 IO page
tables, therefore eliminating the VM exits for guest IOMMU mapping
operations. For unmapping operations, VM exits to perform the IOTLB
flush are still unavoidable.
Guest hibernation and resume are not supported by this initial
implementation. The guest-owned stage-1 page tables reside in guest
memory and are preserved in the hibernation image. However, the image
does not by itself preserve the Hyper-V device-domain objects or their
device attachments, and the current pvIOMMU interface does not define
whether or how Hyper-V restores that state.
To identify a device in its hypercall interface, the driver looks up the
logical device ID prefix registered for the device's PCI domain (see the
logical device ID registry in hv_common.c) and combines it with the PCI
function number of the endpoint device.
Co-developed-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Co-developed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Signed-off-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Signed-off-by: Yu Zhang <zhangyu1@linux.microsoft.com>
Reviewed-by: Jacob Pan <jacob.pan@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
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Create hyperv subdirectory under drivers/iommu in anticipation of more
Hyper-V related files from upcoming PCI passthrough and PV-IOMMU patches.
Also, the current file hyperv-iommu.c actually implements irq remapping on
x86, so rename to more appropriate hv-irq-remap-x86.c and move it under
the new hyperv subdirectory. Since this file implements irq_remap_ops
exposed by drivers/iommu/irq_remapping.h, it cannot be relocated to the
irq directory. This is in sync with other backend directories like amd
and intel there.
Lastly, this file should not be tied to CONFIG_HYPERV_IOMMU, but to
CONFIG_HYPERV and CONFIG_IRQ_REMAP.
Signed-off-by: Mukesh R <mrathor@linux.microsoft.com>
Reviewed-by: Jacob Pan <jacob.pan@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
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