Unlike x86 which explicitly distinguishes guest traps and host traps (VM
exits vs. IDT trap gates), risc-v unifies them to a single trap gate
with bits in multiple CSRs representing the privilege mode before the
trap. This commit follows this design.
Due to this change the arch_vcpu_thread in risc-v was basically
abandoned, and used only as a first-time entry point to guest, with the
rest of the original x86 arch_vcpu_thread being re-implemented following
above single-entry design.
Save/restore routine is also being re-implemented to account for
both hs-mode traps and v-mode traps. sscratch is used to mark the place
where the context is being saved to/restored from. When sscratch is
zero at the time of the trap, the context is saved into host stack.
When sscratch is non-zero, the context is saved to vcpu->arch.regs
(similar for restore).
Tracked-On: #8841
Signed-off-by: Yifan Liu <yifan1.liu@intel.com>
Signed-off-by: Haicheng Li <haicheng.li@intel.com>
Acked-by: Wang Yu1 <yu1.wang@intel.com>
This patch integrates RISC-V with the common IRQ framework:
- Register software and timer interrupt handlers via request_irq().
- Refine dispatch_interrupt() to handle interrupts via do_irq().
Tracked-On: #8845
Signed-off-by: Shiqing Gao <shiqing.gao@intel.com>
Acked-by: Wang Yu1 <yu1.wang@intel.com>
There are two reasons to use inline functions and numbered-CSR
instead of simply string concat.
1, With old style, CSR names have to be written in lower cases
and cannot prefix anything. This sometimes causes confusion with
variables. For example, csr_write(sstatus, sstatus). Changing to
inline function with MACROs can reduce confusion:
csr_write(CSR_SSTATUS, sstatus)
2, Using number macros allows us to manage CSRs in a more organized
way. We can now put CSR names in variables or arrays and access them
using variables instead of just string names.
Tracked-On: #8838
Signed-off-by: Yifan Liu <yifan1.liu@intel.com>
Acked-by: Wang Yu1 <yu1.wang@intel.com>
This patch implements interrupt initialization and the basic
exception/interrupt handling flow on RISC-V.
init_interrupt() needs to be invoked during CPU initialization to
set up the trap vector and enable the interrupt.
RISC-V exception and interrupt handling includes:
- Saving and restoring CPU registers around traps
- Implementing handlers for:
- Supervisor software interrupt
- Supervisor timer interrupt
- Halting the CPU for all other interrupts and exceptions
------
TODOs:
1. add support for registering interrupt handlers via request_irq() and
further adoption of the common IRQ framework.
2. add support for external interrupt.
Tracked-On: #8813
Signed-off-by: Haicheng Li <haicheng.li@intel.com>
Co-developed-by: Shiqing Gao <shiqing.gao@intel.com>
Signed-off-by: Shiqing Gao <shiqing.gao@intel.com>
Reviewed-by: Yifan Liu <yifan1.liu@intel.com>
Acked-by: Wang, Yu1 <yu1.wang@intel.com>
