On Tue, May 20, 2025 at 06:41:03PM +0800, Meng Zhuo wrote:
> This patch adds host satp mode while kvm/host cpu satp mode is not
> set.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2931
> Signed-off-by: Meng Zhuo <mengz...@iscas.ac.cn>
> ---
Please provide a changelog here. I had to go reread the comments on v1 to
guess at what might have changed.
> target/riscv/cpu.c | 3 +--
> target/riscv/cpu.h | 1 +
> target/riscv/kvm/kvm-cpu.c | 20 +++++++++++++++++++-
> 3 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index d92874baa0..a84edd3a3b 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -433,8 +433,7 @@ const char *satp_mode_str(uint8_t satp_mode, bool
> is_32_bit)
> g_assert_not_reached();
> }
>
> -static void set_satp_mode_max_supported(RISCVCPU *cpu,
> - uint8_t satp_mode)
> +void set_satp_mode_max_supported(RISCVCPU *cpu, uint8_t satp_mode)
In v1 I suggested we add some sanity checking to this function to ensure
we can never set an invalid mode (one that's higher than the max
supported).
> {
> bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
> const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index b56d3afa69..d7136f1d72 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -915,6 +915,7 @@ char *riscv_cpu_get_name(RISCVCPU *cpu);
>
> void riscv_cpu_finalize_features(RISCVCPU *cpu, Error **errp);
> void riscv_add_satp_mode_properties(Object *obj);
> +void set_satp_mode_max_supported(RISCVCPU *cpu, uint8_t satp_mode);
> bool riscv_cpu_accelerator_compatible(RISCVCPU *cpu);
>
> /* CSR function table */
> diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
> index 82f9728636..18fbca1a08 100644
> --- a/target/riscv/kvm/kvm-cpu.c
> +++ b/target/riscv/kvm/kvm-cpu.c
> @@ -999,6 +999,23 @@ static void kvm_riscv_destroy_scratch_vcpu(KVMScratchCPU
> *scratch)
> close(scratch->kvmfd);
> }
>
> +static void kvm_riscv_init_satp_mode(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
> +{
> + CPURISCVState *env = &cpu->env;
> + struct kvm_one_reg reg;
> + int ret;
> + uint64_t val;
> +
> + reg.id = RISCV_CONFIG_REG(env, satp_mode);
> + reg.addr = (uint64_t)&val;
> + ret = ioctl(kvmcpu->cpufd, KVM_GET_ONE_REG, ®);
> + if (ret != 0) {
> + error_report("Unable to retrieve satp from host, error %d", ret);
This will output "Unable..., error -1" on error. We should output at least
the errno and preferably the errno string. I see that this is just a copy
of a pattern used throughout this file though, so we need a patch fixing
all of the ioctl call error_reports.
> + }
> +
> + set_satp_mode_max_supported(cpu, val);
> +}
> +
> static void kvm_riscv_init_machine_ids(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
> {
> struct kvm_one_reg reg;
> @@ -1302,6 +1319,7 @@ static void riscv_init_kvm_registers(Object *cpu_obj)
> kvm_riscv_init_machine_ids(cpu, &kvmcpu);
> kvm_riscv_init_misa_ext_mask(cpu, &kvmcpu);
> kvm_riscv_init_cfg(cpu, &kvmcpu);
> + kvm_riscv_init_satp_mode(cpu, &kvmcpu);
>
> kvm_riscv_destroy_scratch_vcpu(&kvmcpu);
> }
> @@ -1980,7 +1998,7 @@ static bool kvm_cpu_realize(CPUState *cs, Error **errp)
> }
> }
>
> - return true;
> + return true;
> }
>
> void riscv_kvm_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
> --
> 2.39.5
>
>
Otherwise,
Reviewed-by: Andrew Jones <ajo...@ventanamicro.com>
