This series implements the "KVM Guset Debug" feature on RISC-V. This is an existing feature which is already supported by some other arches. It allows us to debug a RISC-V KVM guest from GDB in host side. As the first stage, the software breakpoints (ebreak instruction) is implemented. HW breakpoints support will come later after a synthetically consideration with the SBI debug trigger extension. A selftest case was added in this series. Manual test was done on QEMU RISC-V hypervisor emulator. (add '-s' to enable the gdbserver in QEMU) This series is based on Linux 6.9-rc1 and also available at: https://github.com/Du-Chao/kvm-riscv/tree/guest_debug_sw_v3_6.9-rc1 The matched QEMU is available at: https://github.com/Du-Chao/qemu/tree/riscv_gd_sw Changes from v3->v4: - Some optimization on the testcase as per review comments. Changes from v2->v3: - Rebased on Linux 6.9-rc1. - Use BIT() in the macro definition. - set/clear the bit EXC_BREAKPOINT explicitly. - change the testcase name to ebreak_test. - test the scenario without GUEST_DEBUG. vm_install_exception_handler() is used thanks to Haibo's patch. Changes from v1->v2: - Rebased on Linux 6.8-rc6. - Maintain a hedeleg in "struct kvm_vcpu_config" for each VCPU. - Update the HEDELEG csr in kvm_arch_vcpu_load(). Changes from RFC->v1: - Rebased on Linux 6.8-rc2. - Merge PATCH1 and PATCH2 into one patch. - kselftest case added. v3 link: https://lore.kernel.org/kvm/20240327075526.31855-1-duchao@xxxxxxxxxxxxxxxxxx v2 link: https://lore.kernel.org/kvm/20240301013545.10403-1-duchao@xxxxxxxxxxxxxxxxxx v1 link: https://lore.kernel.org/kvm/20240206074931.22930-1-duchao@xxxxxxxxxxxxxxxxxx RFC link: https://lore.kernel.org/kvm/20231221095002.7404-1-duchao@xxxxxxxxxxxxxxxxxx Chao Du (3): RISC-V: KVM: Implement kvm_arch_vcpu_ioctl_set_guest_debug() RISC-V: KVM: Handle breakpoint exits for VCPU RISC-V: KVM: selftests: Add ebreak test support arch/riscv/include/asm/kvm_host.h | 12 +++ arch/riscv/kvm/main.c | 18 +--- arch/riscv/kvm/vcpu.c | 16 +++- arch/riscv/kvm/vcpu_exit.c | 4 + arch/riscv/kvm/vm.c | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../testing/selftests/kvm/riscv/ebreak_test.c | 82 +++++++++++++++++++ 7 files changed, 116 insertions(+), 18 deletions(-) create mode 100644 tools/testing/selftests/kvm/riscv/ebreak_test.c -- 2.17.1
