Difference between revisions of "Virtual I/O Internals"
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==RPC Mode== | ==RPC Mode== | ||
[[File:Mediated Device Access MMU.png|thumb|A slide describing Extended Page Table & MMU used in mediated device management.]] | [[File:Mediated Device Access MMU.png|thumb|A slide describing Extended Page Table & MMU used in mediated device management.]] | ||
=== Instruction Execution === | === Instruction Execution === | ||
RPC Mode moves instruction information across a virtual function interface (VF) using [https://infogalactic.com/info/Remote_procedure_call Remote Procedure Calls] generally by way of [https://infogalactic.com/info/Interrupt soft interrupt] (IOCTLs). Guest GPU instructions passed from the guest as Remote Procedure Calls are [https://infogalactic.com/info/Just-in-time_compilation Just-in-time] recompiled on the host for execution by a device driver. | RPC Mode moves instruction information across a virtual function interface (VF) using [https://infogalactic.com/info/Remote_procedure_call Remote Procedure Calls] generally by way of [https://infogalactic.com/info/Interrupt soft interrupt] (IOCTLs). Guest GPU instructions passed from the guest as Remote Procedure Calls are [https://infogalactic.com/info/Just-in-time_compilation Just-in-time] recompiled on the host for execution by a device driver. | ||
Revision as of 20:56, 21 April 2022
The following document will attempt to detail the internals of a Virtual Function IO (VFIO) driven Mediated Device (Mdev).
| RPC Mode | SR-IOV Mode |
|---|---|
| Host requires insight about guest of workload. | Host ignorance of guest workload. |
| Error reporting. | No guest driver error reporting. |
| In depth dynamic monitoring. | Basic dynamic monitoring. |
| Software defined MMU guest separation. | Firmware defined MMU guest separation. |
| Requires deferred instructions to be supported by host software (support libraries). | Guest is ignorant of host supported software such as support libraries. |
RPC Mode
Instruction Execution
RPC Mode moves instruction information across a virtual function interface (VF) using Remote Procedure Calls generally by way of soft interrupt (IOCTLs). Guest GPU instructions passed from the guest as Remote Procedure Calls are Just-in-time recompiled on the host for execution by a device driver.
Memory Management
Guests are presented with emulated memory regions (indirect emulated communication requiring a VM-exit) or passthrough memory regions (direct communication requiring no VM-exit).
RPC Mode Requirements:
Sensitive Instruction List.
Instruction Shim/Binary Translator.
HPA<->GPA Boundary Enforcement.
SR-IOV Mode
SR-IOV Mode involves the communication of instructions from a virtual function (VF) though direct communication to the PCI BAR.
RPC Mode Requirements:
Device SR-IOV support.
HPA<->GPA Boundary Enforcement.