diff options
Diffstat (limited to 'Documentation/arch')
| -rw-r--r-- | Documentation/arch/arm64/cpu-feature-registers.rst | 2 | ||||
| -rw-r--r-- | Documentation/arch/loongarch/irq-chip-model.rst | 64 |
2 files changed, 66 insertions, 0 deletions
diff --git a/Documentation/arch/arm64/cpu-feature-registers.rst b/Documentation/arch/arm64/cpu-feature-registers.rst index 44f9bd78539d..253e9743de2f 100644 --- a/Documentation/arch/arm64/cpu-feature-registers.rst +++ b/Documentation/arch/arm64/cpu-feature-registers.rst @@ -152,6 +152,8 @@ infrastructure: +------------------------------+---------+---------+ | DIT | [51-48] | y | +------------------------------+---------+---------+ + | MPAM | [43-40] | n | + +------------------------------+---------+---------+ | SVE | [35-32] | y | +------------------------------+---------+---------+ | GIC | [27-24] | n | diff --git a/Documentation/arch/loongarch/irq-chip-model.rst b/Documentation/arch/loongarch/irq-chip-model.rst index 6dd48256e39f..a7ecce11e445 100644 --- a/Documentation/arch/loongarch/irq-chip-model.rst +++ b/Documentation/arch/loongarch/irq-chip-model.rst @@ -85,6 +85,70 @@ to CPUINTC directly:: | Devices | +---------+ +Virtual Extended IRQ model +========================== + +In this model, IPI (Inter-Processor Interrupt) and CPU Local Timer interrupt +go to CPUINTC directly, CPU UARTS interrupts go to PCH-PIC, while all other +devices interrupts go to PCH-PIC/PCH-MSI and gathered by V-EIOINTC (Virtual +Extended I/O Interrupt Controller), and then go to CPUINTC directly:: + + +-----+ +-------------------+ +-------+ + | IPI |--> | CPUINTC(0-255vcpu)| <-- | Timer | + +-----+ +-------------------+ +-------+ + ^ + | + +-----------+ + | V-EIOINTC | + +-----------+ + ^ ^ + | | + +---------+ +---------+ + | PCH-PIC | | PCH-MSI | + +---------+ +---------+ + ^ ^ ^ + | | | + +--------+ +---------+ +---------+ + | UARTs | | Devices | | Devices | + +--------+ +---------+ +---------+ + + +Description +----------- +V-EIOINTC (Virtual Extended I/O Interrupt Controller) is an extension of +EIOINTC, it only works in VM mode which runs in KVM hypervisor. Interrupts can +be routed to up to four vCPUs via standard EIOINTC, however with V-EIOINTC +interrupts can be routed to up to 256 virtual cpus. + +With standard EIOINTC, interrupt routing setting includes two parts: eight +bits for CPU selection and four bits for CPU IP (Interrupt Pin) selection. +For CPU selection there is four bits for EIOINTC node selection, four bits +for EIOINTC CPU selection. Bitmap method is used for CPU selection and +CPU IP selection, so interrupt can only route to CPU0 - CPU3 and IP0-IP3 in +one EIOINTC node. + +With V-EIOINTC it supports to route more CPUs and CPU IP (Interrupt Pin), +there are two newly added registers with V-EIOINTC. + +EXTIOI_VIRT_FEATURES +-------------------- +This register is read-only register, which indicates supported features with +V-EIOINTC. Feature EXTIOI_HAS_INT_ENCODE and EXTIOI_HAS_CPU_ENCODE is added. + +Feature EXTIOI_HAS_INT_ENCODE is part of standard EIOINTC. If it is 1, it +indicates that CPU Interrupt Pin selection can be normal method rather than +bitmap method, so interrupt can be routed to IP0 - IP15. + +Feature EXTIOI_HAS_CPU_ENCODE is entension of V-EIOINTC. If it is 1, it +indicates that CPU selection can be normal method rather than bitmap method, +so interrupt can be routed to CPU0 - CPU255. + +EXTIOI_VIRT_CONFIG +------------------ +This register is read-write register, for compatibility intterupt routed uses +the default method which is the same with standard EIOINTC. If the bit is set +with 1, it indicated HW to use normal method rather than bitmap method. + Advanced Extended IRQ model =========================== |