[PATCH v4 0/3] target/riscv/kvm: QEMU support for KVM Guest Debug on RISC-V

[Chao Du <duchao@eswincomputing.com>]

This series implements QEMU KVM Guest Debug on RISC-V, with which we
could debug RISC-V KVM guest from the host side, using software
breakpoints.

This series is based on riscv-to-apply.next branch and is also
available at:
https://github.com/Du-Chao/alistair23-qemu/tree/riscv-to-apply.next.0606

The corresponding KVM side patches have been merged already:
https://lore.kernel.org/kvm/20240402062628.5425-1-duchao@eswincomputing.com/

A TODO list which will be added later:
1. HW breakpoints support
2. A 'corner case' in which the debug exception is not inserted by the
debugger, need to be re-injected to the guest.

v3,v4:
- rebased.

v2->v2 resend:
- add the type conversion in patch #1 to avoid warnings

v1->v2:
- squash patch #2 into #1
- check the instruction length from the tail two bits, instead of passing the
  length information by parameters.

RFC->v1:
- Rebased on riscv-to-apply.next
- use configs/ definition to conditionalize debug support

v2 link:
https://lore.kernel.org/qemu-riscv/20240528080759.26439-1-duchao@eswincomputing.com/
v1 link:
https://lore.kernel.org/qemu-riscv/20240527021916.12953-1-duchao@eswincomputing.com/
RFC link:
https://lore.kernel.org/qemu-riscv/20231221094923.7349-1-duchao@eswincomputing.com/

Chao Du (3):
  target/riscv/kvm: add software breakpoints support
  target/riscv/kvm: handle the exit with debug reason
  target/riscv/kvm: define TARGET_KVM_HAVE_GUEST_DEBUG

 configs/targets/riscv64-softmmu.mak |  1 +
 target/riscv/kvm/kvm-cpu.c          | 89 +++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)

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2.17.1