Re: [PATCH RFC v5 06/12] target/riscv: Support start kernel directly by KVM

[Alistair Francis <alistair23@gmail.com>]

On Mon, Apr 12, 2021 at 4:56 PM Yifei Jiang <jiangyifei@huawei.com> wrote:
>
> Get kernel and fdt start address in virt.c, and pass them to KVM
> when cpu reset. In addition, add kvm_riscv.h to place riscv specific
> interface.
>
> Signed-off-by: Yifei Jiang <jiangyifei@huawei.com>
> Signed-off-by: Yipeng Yin <yinyipeng1@huawei.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  hw/riscv/boot.c          | 11 +++++++++++
>  hw/riscv/virt.c          |  7 +++++++
>  include/hw/riscv/boot.h  |  1 +
>  target/riscv/cpu.c       |  8 ++++++++
>  target/riscv/cpu.h       |  3 +++
>  target/riscv/kvm-stub.c  | 25 +++++++++++++++++++++++++
>  target/riscv/kvm.c       | 13 +++++++++++++
>  target/riscv/kvm_riscv.h | 24 ++++++++++++++++++++++++
>  target/riscv/meson.build |  2 +-
>  9 files changed, 93 insertions(+), 1 deletion(-)
>  create mode 100644 target/riscv/kvm-stub.c
>  create mode 100644 target/riscv/kvm_riscv.h
>
> diff --git a/hw/riscv/boot.c b/hw/riscv/boot.c
> index 0d38bb7426..b9741a647d 100644
> --- a/hw/riscv/boot.c
> +++ b/hw/riscv/boot.c
> @@ -290,3 +290,14 @@ void riscv_setup_rom_reset_vec(MachineState *machine, RISCVHartArrayState *harts
>
>      return;
>  }
> +
> +void riscv_setup_direct_kernel(hwaddr kernel_addr, hwaddr fdt_addr)
> +{
> +    CPUState *cs;
> +
> +    for (cs = first_cpu; cs; cs = CPU_NEXT(cs)) {
> +        RISCVCPU *riscv_cpu = RISCV_CPU(cs);
> +        riscv_cpu->env.kernel_addr = kernel_addr;
> +        riscv_cpu->env.fdt_addr = fdt_addr;
> +    }
> +}
> diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> index c0dc69ff33..4a1fca139c 100644
> --- a/hw/riscv/virt.c
> +++ b/hw/riscv/virt.c
> @@ -728,6 +728,13 @@ static void virt_machine_init(MachineState *machine)
>                                virt_memmap[VIRT_MROM].size, kernel_entry,
>                                fdt_load_addr, machine->fdt);
>
> +    /*
> +     * Only direct boot kernel is currently supported for KVM VM,
> +     * So here setup kernel start address and fdt address.
> +     * TODO:Support firmware loading and integrate to TCG start
> +     */
> +    riscv_setup_direct_kernel(kernel_entry, fdt_load_addr);
> +
>      /* SiFive Test MMIO device */
>      sifive_test_create(memmap[VIRT_TEST].base);
>
> diff --git a/include/hw/riscv/boot.h b/include/hw/riscv/boot.h
> index 11a21dd584..28d838cc29 100644
> --- a/include/hw/riscv/boot.h
> +++ b/include/hw/riscv/boot.h
> @@ -51,5 +51,6 @@ void riscv_rom_copy_firmware_info(MachineState *machine, hwaddr rom_base,
>                                    hwaddr rom_size,
>                                    uint32_t reset_vec_size,
>                                    uint64_t kernel_entry);
> +void riscv_setup_direct_kernel(hwaddr kernel_addr, hwaddr fdt_addr);
>
>  #endif /* RISCV_BOOT_H */
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 7d6ed80f6b..dd34ab4978 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -29,6 +29,8 @@
>  #include "hw/qdev-properties.h"
>  #include "migration/vmstate.h"
>  #include "fpu/softfloat-helpers.h"
> +#include "sysemu/kvm.h"
> +#include "kvm_riscv.h"
>
>  /* RISC-V CPU definitions */
>
> @@ -361,6 +363,12 @@ static void riscv_cpu_reset(DeviceState *dev)
>      cs->exception_index = EXCP_NONE;
>      env->load_res = -1;
>      set_default_nan_mode(1, &env->fp_status);
> +
> +#ifndef CONFIG_USER_ONLY
> +    if (kvm_enabled()) {
> +        kvm_riscv_reset_vcpu(cpu);
> +    }
> +#endif
>  }
>
>  static void riscv_cpu_disas_set_info(CPUState *s, disassemble_info *info)
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 0a33d387ba..a489d94187 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -243,6 +243,9 @@ struct CPURISCVState {
>
>      /* Fields from here on are preserved across CPU reset. */
>      QEMUTimer *timer; /* Internal timer */
> +
> +    hwaddr kernel_addr;
> +    hwaddr fdt_addr;
>  };
>
>  OBJECT_DECLARE_TYPE(RISCVCPU, RISCVCPUClass,
> diff --git a/target/riscv/kvm-stub.c b/target/riscv/kvm-stub.c
> new file mode 100644
> index 0000000000..39b96fe3f4
> --- /dev/null
> +++ b/target/riscv/kvm-stub.c
> @@ -0,0 +1,25 @@
> +/*
> + * QEMU KVM RISC-V specific function stubs
> + *
> + * Copyright (c) 2020 Huawei Technologies Co., Ltd
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include "qemu/osdep.h"
> +#include "cpu.h"
> +#include "kvm_riscv.h"
> +
> +void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
> +{
> +    abort();
> +}
> diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
> index 9d1441952a..79c931acb4 100644
> --- a/target/riscv/kvm.c
> +++ b/target/riscv/kvm.c
> @@ -37,6 +37,7 @@
>  #include "hw/irq.h"
>  #include "qemu/log.h"
>  #include "hw/loader.h"
> +#include "kvm_riscv.h"
>
>  static __u64 kvm_riscv_reg_id(CPURISCVState *env, __u64 type, __u64 idx)
>  {
> @@ -440,6 +441,18 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
>      return 0;
>  }
>
> +void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
> +{
> +    CPURISCVState *env = &cpu->env;
> +
> +    if (!kvm_enabled()) {
> +        return;
> +    }
> +    env->pc = cpu->env.kernel_addr;
> +    env->gpr[10] = kvm_arch_vcpu_id(CPU(cpu)); /* a0 */
> +    env->gpr[11] = cpu->env.fdt_addr;          /* a1 */
> +}
> +
>  bool kvm_arch_cpu_check_are_resettable(void)
>  {
>      return true;
> diff --git a/target/riscv/kvm_riscv.h b/target/riscv/kvm_riscv.h
> new file mode 100644
> index 0000000000..f38c82bf59
> --- /dev/null
> +++ b/target/riscv/kvm_riscv.h
> @@ -0,0 +1,24 @@
> +/*
> + * QEMU KVM support -- RISC-V specific functions.
> + *
> + * Copyright (c) 2020 Huawei Technologies Co., Ltd
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef QEMU_KVM_RISCV_H
> +#define QEMU_KVM_RISCV_H
> +
> +void kvm_riscv_reset_vcpu(RISCVCPU *cpu);
> +
> +#endif
> diff --git a/target/riscv/meson.build b/target/riscv/meson.build
> index 32afd6e882..0f63e3824d 100644
> --- a/target/riscv/meson.build
> +++ b/target/riscv/meson.build
> @@ -23,7 +23,7 @@ riscv_ss.add(files(
>    'vector_helper.c',
>    'translate.c',
>  ))
> -riscv_ss.add(when: 'CONFIG_KVM', if_true: files('kvm.c'))
> +riscv_ss.add(when: 'CONFIG_KVM', if_true: files('kvm.c'), if_false: files('kvm-stub.c'))
>
>  riscv_softmmu_ss = ss.source_set()
>  riscv_softmmu_ss.add(files(
> --
> 2.19.1
>
>