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[PATCH 1/7] hw/riscv: acpi: only create RHCT MMU entry for supported types

Paolo Bonzini posted 7 patches 1 month, 2 weeks ago
[PATCH 1/7] hw/riscv: acpi: only create RHCT MMU entry for supported types
Posted by Paolo Bonzini 1 month, 2 weeks ago 
Do not create the RHCT MMU type entry for RV32 CPUs, since it
only has definitions for SV39/SV48/SV57.  Likewise, check that
satp_mode_max_from_map() will actually return a valid value, skipping
the MMU type entry if all MMU types were disabled on the command line.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/riscv/virt-acpi-build.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
index 1ad68005085..2b374ebacbf 100644
--- a/hw/riscv/virt-acpi-build.c
+++ b/hw/riscv/virt-acpi-build.c
@@ -262,6 +262,7 @@ static void build_rhct(GArray *table_data,
     RISCVCPU *cpu = &s->soc[0].harts[0];
     uint32_t mmu_offset = 0;
     uint8_t satp_mode_max;
+    bool rv32 = riscv_cpu_is_32bit(cpu);
     g_autofree char *isa = NULL;
 
     AcpiTable table = { .sig = "RHCT", .rev = 1, .oem_id = s->oem_id,
@@ -281,7 +282,8 @@ static void build_rhct(GArray *table_data,
         num_rhct_nodes++;
     }
 
-    if (cpu->cfg.satp_mode.supported != 0) {
+    if (!rv32 && cpu->cfg.satp_mode.supported != 0 &&
+        (cpu->cfg.satp_mode.map & ~(1 << VM_1_10_MBARE))) {
         num_rhct_nodes++;
     }
 
@@ -341,7 +343,8 @@ static void build_rhct(GArray *table_data,
     }
 
     /* MMU node structure */
-    if (cpu->cfg.satp_mode.supported != 0) {
+    if (!rv32 && cpu->cfg.satp_mode.supported != 0 &&
+        (cpu->cfg.satp_mode.map & ~(1 << VM_1_10_MBARE))) {
         satp_mode_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
         mmu_offset = table_data->len - table.table_offset;
         build_append_int_noprefix(table_data, 2, 2);    /* Type */
@@ -356,7 +359,7 @@ static void build_rhct(GArray *table_data,
         } else if (satp_mode_max == VM_1_10_SV39) {
             build_append_int_noprefix(table_data, 0, 1);    /* Sv39 */
         } else {
-            assert(1);
+            g_assert_not_reached();
         }
     }
 
-- 
2.48.1
Re: [PATCH 1/7] hw/riscv: acpi: only create RHCT MMU entry for supported types
Posted by Alistair Francis 4 weeks, 1 day ago 
On Wed, Feb 19, 2025 at 2:58 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> Do not create the RHCT MMU type entry for RV32 CPUs, since it
> only has definitions for SV39/SV48/SV57.  Likewise, check that

I don't have access to the spec, so I'm going to take your word on this

> satp_mode_max_from_map() will actually return a valid value, skipping
> the MMU type entry if all MMU types were disabled on the command line.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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

Alistair

> ---
>  hw/riscv/virt-acpi-build.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
> index 1ad68005085..2b374ebacbf 100644
> --- a/hw/riscv/virt-acpi-build.c
> +++ b/hw/riscv/virt-acpi-build.c
> @@ -262,6 +262,7 @@ static void build_rhct(GArray *table_data,
>      RISCVCPU *cpu = &s->soc[0].harts[0];
>      uint32_t mmu_offset = 0;
>      uint8_t satp_mode_max;
> +    bool rv32 = riscv_cpu_is_32bit(cpu);
>      g_autofree char *isa = NULL;
>
>      AcpiTable table = { .sig = "RHCT", .rev = 1, .oem_id = s->oem_id,
> @@ -281,7 +282,8 @@ static void build_rhct(GArray *table_data,
>          num_rhct_nodes++;
>      }
>
> -    if (cpu->cfg.satp_mode.supported != 0) {
> +    if (!rv32 && cpu->cfg.satp_mode.supported != 0 &&
> +        (cpu->cfg.satp_mode.map & ~(1 << VM_1_10_MBARE))) {
>          num_rhct_nodes++;
>      }
>
> @@ -341,7 +343,8 @@ static void build_rhct(GArray *table_data,
>      }
>
>      /* MMU node structure */
> -    if (cpu->cfg.satp_mode.supported != 0) {
> +    if (!rv32 && cpu->cfg.satp_mode.supported != 0 &&
> +        (cpu->cfg.satp_mode.map & ~(1 << VM_1_10_MBARE))) {
>          satp_mode_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
>          mmu_offset = table_data->len - table.table_offset;
>          build_append_int_noprefix(table_data, 2, 2);    /* Type */
> @@ -356,7 +359,7 @@ static void build_rhct(GArray *table_data,
>          } else if (satp_mode_max == VM_1_10_SV39) {
>              build_append_int_noprefix(table_data, 0, 1);    /* Sv39 */
>          } else {
> -            assert(1);
> +            g_assert_not_reached();
>          }
>      }
>
> --
> 2.48.1
>
>
Re: [PATCH 1/7] hw/riscv: acpi: only create RHCT MMU entry for supported types
Posted by Paolo Bonzini 4 weeks ago 
On Thu, Mar 6, 2025 at 2:13 AM Alistair Francis <alistair23@gmail.com> wrote:
>
> On Wed, Feb 19, 2025 at 2:58 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> > Do not create the RHCT MMU type entry for RV32 CPUs, since it
> > only has definitions for SV39/SV48/SV57.  Likewise, check that
>
> I don't have access to the spec, so I'm going to take your word on this

Thanks for reviewing - the closest thing I found to a spec are two
Google documents linked from
https://github.com/riscv-non-isa/riscv-acpi/issues/16 and
https://github.com/riscv-non-isa/riscv-acpi/issues/18.

In particular, the MMU type documentation can be found at
https://drive.google.com/file/d/1sKbOa8m1UZw1JkquZYe3F1zQBN1xXsaf/view:

MMU Type (byte length=1, byte offset=7)
0: Sv39
1: Sv48
2: Sv57
All other values are reserved.

Paolo

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