[PATCH v6] target/riscv/kvm: add max_satp_mode from host cpu

[PATCH v6] target/riscv/kvm: add max_satp_mode from host cpu

[Meng Zhuo]

This patch adds max_satp_mode from host kvm cpu setting.

Tested on: Milkv Megrez (Eswin 7700x)

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2931
Signed-off-by: Meng Zhuo <mengzhuo@iscas.ac.cn>
---
Change in v6:
- Rebase on https://github.com/alistair23/qemu/tree/riscv-to-apply.next
- Minor change in title

Change in v5:
- Adds R-B comment from Andrew Jones

Change in v4:
- Adds changelog in commit message
- Link to v3: https://lists.nongnu.org/archive/html/qemu-devel/2025-05/msg04629.html

Change in v3:
- Rebase on https://github.com/alistair23/qemu/tree/riscv-to-apply.next
  as requested
- Link to v2: https://lists.nongnu.org/archive/html/qemu-devel/2025-04/msg05203.html

Changes in v2:
- use set_satp_mode_max_supported instead of hard code
- Link to v1: https://lists.nongnu.org/archive/html/qemu-devel/2025-04/msg05094.html
---
 target/riscv/kvm/kvm-cpu.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index e1a04be20f..502d33f404 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -999,6 +999,19 @@ static void kvm_riscv_destroy_scratch_vcpu(KVMScratchCPU *scratch)
     close(scratch->kvmfd);
 }
 
+static void kvm_riscv_init_max_satp_mode(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
+{
+    struct kvm_one_reg reg;
+    int ret;
+
+    reg.id = RISCV_CONFIG_REG(satp_mode);
+    reg.addr = (uint64_t)&cpu->cfg.max_satp_mode;
+    ret = ioctl(kvmcpu->cpufd, KVM_GET_ONE_REG, &reg);
+    if (ret != 0) {
+        error_report("Unable to retrieve satp mode from host, error %d", ret);
+    }
+}
+
 static void kvm_riscv_init_machine_ids(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
 {
     struct kvm_one_reg reg;
@@ -1302,6 +1315,7 @@ 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_max_satp_mode(cpu, &kvmcpu);
 
     kvm_riscv_destroy_scratch_vcpu(&kvmcpu);
 }
@@ -1985,7 +1999,7 @@ 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

Re: [PATCH v6] target/riscv/kvm: add max_satp_mode from host cpu

[Alistair Francis]

On Fri, Jun 6, 2025 at 1:45 PM Meng Zhuo <mengzhuo@iscas.ac.cn> wrote:
>
> This patch adds max_satp_mode from host kvm cpu setting.
>
> Tested on: Milkv Megrez (Eswin 7700x)
>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2931
> Signed-off-by: Meng Zhuo <mengzhuo@iscas.ac.cn>

Thanks!

Applied to riscv-to-apply.next

Alistair

> ---
> Change in v6:
> - Rebase on https://github.com/alistair23/qemu/tree/riscv-to-apply.next
> - Minor change in title
>
> Change in v5:
> - Adds R-B comment from Andrew Jones
>
> Change in v4:
> - Adds changelog in commit message
> - Link to v3: https://lists.nongnu.org/archive/html/qemu-devel/2025-05/msg04629.html
>
> Change in v3:
> - Rebase on https://github.com/alistair23/qemu/tree/riscv-to-apply.next
>   as requested
> - Link to v2: https://lists.nongnu.org/archive/html/qemu-devel/2025-04/msg05203.html
>
> Changes in v2:
> - use set_satp_mode_max_supported instead of hard code
> - Link to v1: https://lists.nongnu.org/archive/html/qemu-devel/2025-04/msg05094.html
> ---
>  target/riscv/kvm/kvm-cpu.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
> index e1a04be20f..502d33f404 100644
> --- a/target/riscv/kvm/kvm-cpu.c
> +++ b/target/riscv/kvm/kvm-cpu.c
> @@ -999,6 +999,19 @@ static void kvm_riscv_destroy_scratch_vcpu(KVMScratchCPU *scratch)
>      close(scratch->kvmfd);
>  }
>
> +static void kvm_riscv_init_max_satp_mode(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
> +{
> +    struct kvm_one_reg reg;
> +    int ret;
> +
> +    reg.id = RISCV_CONFIG_REG(satp_mode);
> +    reg.addr = (uint64_t)&cpu->cfg.max_satp_mode;
> +    ret = ioctl(kvmcpu->cpufd, KVM_GET_ONE_REG, &reg);
> +    if (ret != 0) {
> +        error_report("Unable to retrieve satp mode from host, error %d", ret);
> +    }
> +}
> +
>  static void kvm_riscv_init_machine_ids(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
>  {
>      struct kvm_one_reg reg;
> @@ -1302,6 +1315,7 @@ 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_max_satp_mode(cpu, &kvmcpu);
>
>      kvm_riscv_destroy_scratch_vcpu(&kvmcpu);
>  }
> @@ -1985,7 +1999,7 @@ 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
>
>