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[PATCH 4/6] target/riscv: Detect sxl to set bit width for RV32 in RV64

LIU Zhiwei posted 6 patches 2 months, 2 weeks ago
There is a newer version of this series
[PATCH 4/6] target/riscv: Detect sxl to set bit width for RV32 in RV64
Posted by LIU Zhiwei 2 months, 2 weeks ago 
From: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>

Ensure correct bit width based on sxl when running RV32 on RV64 QEMU.
This is required as MMU address translations run in S-mode.

Signed-off-by: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
Reviewed-by: Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
---
 target/riscv/cpu_helper.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 6709622dd3..1af83a0a36 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -887,12 +887,14 @@ static int get_physical_address(CPURISCVState *env, hwaddr *physical,
 
     CPUState *cs = env_cpu(env);
     int va_bits = PGSHIFT + levels * ptidxbits + widened;
+    int sxlen = 16UL << riscv_cpu_sxl(env);
+    int sxlen_bytes = sxlen / 8;
 
     if (first_stage == true) {
         target_ulong mask, masked_msbs;
 
-        if (TARGET_LONG_BITS > (va_bits - 1)) {
-            mask = (1L << (TARGET_LONG_BITS - (va_bits - 1))) - 1;
+        if (sxlen > (va_bits - 1)) {
+            mask = (1L << (sxlen - (va_bits - 1))) - 1;
         } else {
             mask = 0;
         }
@@ -961,7 +963,7 @@ restart:
 
         int pmp_prot;
         int pmp_ret = get_physical_address_pmp(env, &pmp_prot, pte_addr,
-                                               sizeof(target_ulong),
+                                               sxlen_bytes,
                                                MMU_DATA_LOAD, PRV_S);
         if (pmp_ret != TRANSLATE_SUCCESS) {
             return TRANSLATE_PMP_FAIL;
@@ -1113,7 +1115,7 @@ restart:
          *   it is no longer valid and we must re-walk the page table.
          */
         MemoryRegion *mr;
-        hwaddr l = sizeof(target_ulong), addr1;
+        hwaddr l = sxlen_bytes, addr1;
         mr = address_space_translate(cs->as, pte_addr, &addr1, &l,
                                      false, MEMTXATTRS_UNSPECIFIED);
         if (memory_region_is_ram(mr)) {
@@ -1126,6 +1128,11 @@ restart:
             *pte_pa = pte = updated_pte;
 #else
             target_ulong old_pte = qatomic_cmpxchg(pte_pa, pte, updated_pte);
+            if (riscv_cpu_sxl(env) == MXL_RV32) {
+                old_pte = qatomic_cmpxchg((uint32_t *)pte_pa, pte, updated_pte);
+            } else {
+                old_pte = qatomic_cmpxchg(pte_pa, pte, updated_pte);
+            }
             if (old_pte != pte) {
                 goto restart;
             }
-- 
2.43.0
Re: [PATCH 4/6] target/riscv: Detect sxl to set bit width for RV32 in RV64
Posted by Alistair Francis 2 months, 2 weeks ago 
On Mon, Jul 1, 2024 at 1:41 PM LIU Zhiwei <zhiwei_liu@linux.alibaba.com> wrote:
>
> From: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
>
> Ensure correct bit width based on sxl when running RV32 on RV64 QEMU.
> This is required as MMU address translations run in S-mode.
>
> Signed-off-by: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
> Reviewed-by: Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
> ---
>  target/riscv/cpu_helper.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index 6709622dd3..1af83a0a36 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -887,12 +887,14 @@ static int get_physical_address(CPURISCVState *env, hwaddr *physical,
>
>      CPUState *cs = env_cpu(env);
>      int va_bits = PGSHIFT + levels * ptidxbits + widened;
> +    int sxlen = 16UL << riscv_cpu_sxl(env);
> +    int sxlen_bytes = sxlen / 8;
>
>      if (first_stage == true) {
>          target_ulong mask, masked_msbs;
>
> -        if (TARGET_LONG_BITS > (va_bits - 1)) {
> -            mask = (1L << (TARGET_LONG_BITS - (va_bits - 1))) - 1;
> +        if (sxlen > (va_bits - 1)) {
> +            mask = (1L << (sxlen - (va_bits - 1))) - 1;
>          } else {
>              mask = 0;
>          }
> @@ -961,7 +963,7 @@ restart:
>
>          int pmp_prot;
>          int pmp_ret = get_physical_address_pmp(env, &pmp_prot, pte_addr,
> -                                               sizeof(target_ulong),
> +                                               sxlen_bytes,
>                                                 MMU_DATA_LOAD, PRV_S);
>          if (pmp_ret != TRANSLATE_SUCCESS) {
>              return TRANSLATE_PMP_FAIL;
> @@ -1113,7 +1115,7 @@ restart:
>           *   it is no longer valid and we must re-walk the page table.
>           */
>          MemoryRegion *mr;
> -        hwaddr l = sizeof(target_ulong), addr1;
> +        hwaddr l = sxlen_bytes, addr1;
>          mr = address_space_translate(cs->as, pte_addr, &addr1, &l,
>                                       false, MEMTXATTRS_UNSPECIFIED);
>          if (memory_region_is_ram(mr)) {
> @@ -1126,6 +1128,11 @@ restart:
>              *pte_pa = pte = updated_pte;
>  #else
>              target_ulong old_pte = qatomic_cmpxchg(pte_pa, pte, updated_pte);

I think you missed removing this line

Alistair

> +            if (riscv_cpu_sxl(env) == MXL_RV32) {
> +                old_pte = qatomic_cmpxchg((uint32_t *)pte_pa, pte, updated_pte);
> +            } else {
> +                old_pte = qatomic_cmpxchg(pte_pa, pte, updated_pte);
> +            }
>              if (old_pte != pte) {
>                  goto restart;
>              }
> --
> 2.43.0
>
>
Re: [PATCH 4/6] target/riscv: Detect sxl to set bit width for RV32 in RV64
Posted by LIU Zhiwei 2 months, 2 weeks ago 
On 2024/7/3 10:33, Alistair Francis wrote:
> On Mon, Jul 1, 2024 at 1:41 PM LIU Zhiwei <zhiwei_liu@linux.alibaba.com> wrote:
>> From: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
>>
>> Ensure correct bit width based on sxl when running RV32 on RV64 QEMU.
>> This is required as MMU address translations run in S-mode.
>>
>> Signed-off-by: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
>> Reviewed-by: Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
>> ---
>>   target/riscv/cpu_helper.c | 15 +++++++++++----
>>   1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
>> index 6709622dd3..1af83a0a36 100644
>> --- a/target/riscv/cpu_helper.c
>> +++ b/target/riscv/cpu_helper.c
>> @@ -887,12 +887,14 @@ static int get_physical_address(CPURISCVState *env, hwaddr *physical,
>>
>>       CPUState *cs = env_cpu(env);
>>       int va_bits = PGSHIFT + levels * ptidxbits + widened;
>> +    int sxlen = 16UL << riscv_cpu_sxl(env);
>> +    int sxlen_bytes = sxlen / 8;
>>
>>       if (first_stage == true) {
>>           target_ulong mask, masked_msbs;
>>
>> -        if (TARGET_LONG_BITS > (va_bits - 1)) {
>> -            mask = (1L << (TARGET_LONG_BITS - (va_bits - 1))) - 1;
>> +        if (sxlen > (va_bits - 1)) {
>> +            mask = (1L << (sxlen - (va_bits - 1))) - 1;
>>           } else {
>>               mask = 0;
>>           }
>> @@ -961,7 +963,7 @@ restart:
>>
>>           int pmp_prot;
>>           int pmp_ret = get_physical_address_pmp(env, &pmp_prot, pte_addr,
>> -                                               sizeof(target_ulong),
>> +                                               sxlen_bytes,
>>                                                  MMU_DATA_LOAD, PRV_S);
>>           if (pmp_ret != TRANSLATE_SUCCESS) {
>>               return TRANSLATE_PMP_FAIL;
>> @@ -1113,7 +1115,7 @@ restart:
>>            *   it is no longer valid and we must re-walk the page table.
>>            */
>>           MemoryRegion *mr;
>> -        hwaddr l = sizeof(target_ulong), addr1;
>> +        hwaddr l = sxlen_bytes, addr1;
>>           mr = address_space_translate(cs->as, pte_addr, &addr1, &l,
>>                                        false, MEMTXATTRS_UNSPECIFIED);
>>           if (memory_region_is_ram(mr)) {
>> @@ -1126,6 +1128,11 @@ restart:
>>               *pte_pa = pte = updated_pte;
>>   #else
>>               target_ulong old_pte = qatomic_cmpxchg(pte_pa, pte, updated_pte);
> I think you missed removing this line

Good catch.  We will fix this in v2 patch set.

Thanks,
Zhiwei

>
> Alistair
>
>> +            if (riscv_cpu_sxl(env) == MXL_RV32) {
>> +                old_pte = qatomic_cmpxchg((uint32_t *)pte_pa, pte, updated_pte);
>> +            } else {
>> +                old_pte = qatomic_cmpxchg(pte_pa, pte, updated_pte);
>> +            }
>>               if (old_pte != pte) {
>>                   goto restart;
>>               }
>> --
>> 2.43.0
>>
>>

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