docs/specs/riscv-aia.rst

1 .. _riscv-aia:
3 RISC-V AIA support for RISC-V machines
6 AIA (Advanced Interrupt Architecture) support is implemented in the ``virt``
7 RISC-V machine for TCG and KVM accelerators.
11 - "aia=aplic": adds one or more APLIC (Advanced Platform Level Interrupt Controller)
13 - "aia=aplic-imsic": adds one or more APLIC device and an IMSIC (Incoming MSI
14    Controller) device for each CPU
18 emulated in userspace versus what is being emulated by an in-kernel irqchip.
21 (m-mode) APLIC and IMSIC (when applicable).
25 - no m-mode is provided, so there is no m-mode APLIC or IMSIC emulation regardless of
27 - with "aia=aplic", s-mode APLIC will be emulated by userspace
28 - with "aia=aplic-imsic" there are two possibilities.  If no additional KVM option
30   machine will use the provided in-kernel APLIC and IMSIC controllers.  If the user
31   chooses to use the irqchip in split mode via "-accel kvm,kernel-irqchip=split",
32   s-mode APLIC will be emulated while using the s-mode IMSIC from the irqchip
38 .. list-table:: How AIA and accel options changes controller emulation
40    :header-rows: 1
42    * - Accel
43      - Accel props
44      - AIA type
45      - APLIC m-mode
46      - IMSIC m-mode
47      - APLIC s-mode
48      - IMSIC s-mode
49    * - tcg
50      - ---
51      - aplic
52      - emul
53      - n/a
54      - emul
55      - n/a
56    * - tcg
57      - ---
58      - aplic-imsic
59      - emul
60      - emul
61      - emul
62      - emul
63    * - kvm
64      - ---
65      - aplic
66      - n/a
67      - n/a
68      - emul
69      - n/a
70    * - kvm
71      - none
72      - aplic-imsic
73      - n/a
74      - n/a
75      - in-kernel
76      - in-kernel
77    * - kvm
78      - irqchip=split
79      - aplic-imsic
80      - n/a
81      - n/a
82      - emul
83      - in-kernel