virt/hyperv/vpci.rst

5 In a Hyper-V guest VM, PCI pass-thru devices (also called
8 Guest device drivers can interact directly with the hardware
12 hypervisor.  The device should appear to the guest just as it
24 and produces the same benefits by allowing a guest device
55 do not appear in the Linux guest's ACPI tables.  vPCI devices
68 in the guest, or if the vPCI device is removed from
95 hv_pci_probe() allocates a guest MMIO range to be used as PCI
99 hv_pci_enter_d0().  When the guest subsequently accesses this
118 guest VM at any time during the life of the VM.  The removal
120 is not under the control of the guest OS.
122 A guest VM is notified of the removal by an unsolicited
123 "Eject" message sent from the host to the guest over the VMBus
131 message to the Linux guest, which the VMBus driver in Linux
135 message also indicates to the guest that Hyper-V has stopped
136 providing support for the vPCI device in the guest.  If the
137 guest were to attempt to access that device's MMIO space, it
142 After sending the Eject message, Hyper-V allows the guest VM
148 cascading errors in the guest because the device is now no
149 longer present from the guest standpoint and accessing the
153 during the guest VM lifecycle, proper synchronization in the
165 MSI, multi-MSI, or MSI-X.  Assigning the guest vCPU that will
175 receive the interrupt before it is forwarded to the guest VM.
200 virtual PCI driver in the guest must make a hypercall to tell
201 Hyper-V which guest vCPU should be interrupted by each
210 arm64 guest VMs because it does not emulate a GICv3 ITS.
221 guest VMs operate in a constrained device environment where
228 By default, Hyper-V pins all guest VM memory in the host
232 guest operating system to program the DMA transfers.  The
233 physical IOMMU prevents a malicious guest from initiating
235 host. From the Linux guest standpoint, such DMA transfers
237 IOMMU in the guest.
245 to a guest VM, that device does not appear in the DSDT, so the
259 host and the Hyper-v vPCI driver in the Linux guest.  Some
261 the guest and host must agree on the vPCI protocol version to
267 guest virtual NUMA node to which it is most closely affined in
270 Guest NUMA node affinity
272 When the vPCI protocol version provides it, the guest NUMA
277 the Linux guest defaults the device NUMA node to 0.  But even
281 the guest receives NUMA node value "0", it could mean NUMA
284 from the guest side.
296 from reading the guest instruction stream to emulate the
305 path between the host and guest.  The back-channel path uses