[RFC v3 12/21] hw/arm/smmu-common: Implement secure state handling in ptw

Tao Tang posted 21 patches 4 months ago
Maintainers: Eric Auger <eric.auger@redhat.com>, Peter Maydell <peter.maydell@linaro.org>
[RFC v3 12/21] hw/arm/smmu-common: Implement secure state handling in ptw
Posted by Tao Tang 4 months ago
Enhance the page table walker to correctly handle secure and non-secure
memory accesses. This change introduces logic to select the appropriate
address space and enforce architectural security policies during walks.

The page table walker now correctly processes Secure Stage 1
translations. Key changes include:

- The get_pte function now uses the security context to fetch table
entries from either the Secure or Non-secure address space.

- The stage 1 walker tracks the security state, respecting the NSCFG
and NSTable attributes. It correctly handles the hierarchical security
model: if a table descriptor in a secure walk has NSTable=1, all
subsequent lookups for that walk are forced into the Non-secure space.
This is a one-way transition, as specified by the architecture.

- A check is added to fault nested translations that produce a Secure
IPA when Secure stage 2 is not supported (SMMU_S_IDR1.SEL2 == 0).

- The final TLB entry is tagged with the correct output address space,
ensuring proper memory isolation.

Stage 2 translations are currently limited to Non-secure lookups. Full
support for Secure Stage 2 translation will be added in a future series.

Signed-off-by: Tao Tang <tangtao1634@phytium.com.cn>
---
 hw/arm/smmu-common.c | 64 +++++++++++++++++++++++++++++++++++++++-----
 hw/arm/trace-events  |  2 +-
 2 files changed, 59 insertions(+), 7 deletions(-)

diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index 5fabe30c75..a092bb5a8d 100644
--- a/hw/arm/smmu-common.c
+++ b/hw/arm/smmu-common.c
@@ -399,20 +399,26 @@ void smmu_iotlb_inv_vmid_s1(SMMUState *s, int vmid)
  * @base_addr[@index]
  */
 static int get_pte(dma_addr_t baseaddr, uint32_t index, uint64_t *pte,
-                   SMMUPTWEventInfo *info)
+                   SMMUPTWEventInfo *info, SMMUSecSID sec_sid)
 {
     int ret;
     dma_addr_t addr = baseaddr + index * sizeof(*pte);
-
+    MemTxAttrs attrs = smmu_get_txattrs(sec_sid);
+    AddressSpace *as = smmu_get_address_space(sec_sid);
+    if (!as) {
+        info->type = SMMU_PTW_ERR_WALK_EABT;
+        info->addr = addr;
+        return -EINVAL;
+    }
     /* TODO: guarantee 64-bit single-copy atomicity */
-    ret = ldq_le_dma(&address_space_memory, addr, pte, MEMTXATTRS_UNSPECIFIED);
+    ret = ldq_le_dma(as, addr, pte, attrs);
 
     if (ret != MEMTX_OK) {
         info->type = SMMU_PTW_ERR_WALK_EABT;
         info->addr = addr;
         return -EINVAL;
     }
-    trace_smmu_get_pte(baseaddr, index, addr, *pte);
+    trace_smmu_get_pte(sec_sid, baseaddr, index, addr, *pte);
     return 0;
 }
 
@@ -543,6 +549,8 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
 
     baseaddr = extract64(tt->ttb, 0, cfg->oas);
     baseaddr &= ~indexmask;
+    int nscfg = tt->nscfg;
+    bool forced_ns = false;  /* Track if NSTable=1 forced NS mode */
 
     while (level < VMSA_LEVELS) {
         uint64_t subpage_size = 1ULL << level_shift(level, granule_sz);
@@ -552,7 +560,10 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
         dma_addr_t pte_addr = baseaddr + offset * sizeof(pte);
         uint8_t ap;
 
-        if (get_pte(baseaddr, offset, &pte, info)) {
+        /* Use NS if forced by previous NSTable=1 or current nscfg */
+        int current_ns = forced_ns || nscfg;
+        SMMUSecSID sec_sid = current_ns ? SMMU_SEC_SID_NS : SMMU_SEC_SID_S;
+        if (get_pte(baseaddr, offset, &pte, info, sec_sid)) {
                 goto error;
         }
         trace_smmu_ptw_level(stage, level, iova, subpage_size,
@@ -577,6 +588,26 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
                     goto error;
                 }
             }
+
+            /*
+             * Hierarchical control of Secure/Non-secure accesses:
+             * If NSTable=1 from Secure space, force all subsequent lookups to
+             * Non-secure space and ignore future NSTable according to
+             * (IHI 0070G.b)13.4.1 Stage 1 page permissions and
+             * (DDI 0487H.a)D8.4.2 Control of Secure or Non-secure memory access
+             */
+            if (!forced_ns) {
+                int new_nstable = PTE_NSTABLE(pte);
+                if (!current_ns && new_nstable) {
+                    /* First transition from Secure to Non-secure */
+                    forced_ns = true;
+                    nscfg = 1;
+                } else if (!forced_ns) {
+                    /* Still in original mode, update nscfg normally */
+                    nscfg = new_nstable;
+                }
+                /* If forced_ns is already true, ignore NSTable bit */
+            }
             level++;
             continue;
         } else if (is_page_pte(pte, level)) {
@@ -619,6 +650,13 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
             goto error;
         }
 
+        tlbe->sec_sid = PTE_NS(pte) ? SMMU_SEC_SID_NS : SMMU_SEC_SID_S;
+        tlbe->entry.target_as = smmu_get_address_space(tlbe->sec_sid);
+        if (!tlbe->entry.target_as) {
+            info->type = SMMU_PTW_ERR_WALK_EABT;
+            info->addr = gpa;
+            goto error;
+        }
         tlbe->entry.translated_addr = gpa;
         tlbe->entry.iova = iova & ~mask;
         tlbe->entry.addr_mask = mask;
@@ -688,7 +726,8 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
         dma_addr_t pte_addr = baseaddr + offset * sizeof(pte);
         uint8_t s2ap;
 
-        if (get_pte(baseaddr, offset, &pte, info)) {
+        /* Use NS as Secure Stage 2 is not implemented (SMMU_S_IDR1.SEL2 == 0)*/
+        if (get_pte(baseaddr, offset, &pte, info, SMMU_SEC_SID_NS)) {
                 goto error;
         }
         trace_smmu_ptw_level(stage, level, ipa, subpage_size,
@@ -741,6 +780,8 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
             goto error_ipa;
         }
 
+        tlbe->sec_sid = SMMU_SEC_SID_NS;
+        tlbe->entry.target_as = &address_space_memory;
         tlbe->entry.translated_addr = gpa;
         tlbe->entry.iova = ipa & ~mask;
         tlbe->entry.addr_mask = mask;
@@ -825,6 +866,17 @@ int smmu_ptw(SMMUState *bs, SMMUTransCfg *cfg, dma_addr_t iova,
         return ret;
     }
 
+    if (!cfg->sel2 && tlbe->sec_sid > SMMU_SEC_SID_NS) {
+        /*
+         * Nested translation with Secure IPA output is not supported if
+         * Secure Stage 2 is not implemented.
+         */
+        info->type = SMMU_PTW_ERR_TRANSLATION;
+        info->stage = SMMU_STAGE_1;
+        tlbe->entry.perm = IOMMU_NONE;
+        return -EINVAL;
+    }
+
     ipa = CACHED_ENTRY_TO_ADDR(tlbe, iova);
     ret = smmu_ptw_64_s2(cfg, ipa, perm, &tlbe_s2, info);
     if (ret) {
diff --git a/hw/arm/trace-events b/hw/arm/trace-events
index 96ebd1b11b..a37e894766 100644
--- a/hw/arm/trace-events
+++ b/hw/arm/trace-events
@@ -16,7 +16,7 @@ smmu_ptw_level(int stage, int level, uint64_t iova, size_t subpage_size, uint64_
 smmu_ptw_invalid_pte(int stage, int level, uint64_t baseaddr, uint64_t pteaddr, uint32_t offset, uint64_t pte) "stage=%d level=%d base@=0x%"PRIx64" pte@=0x%"PRIx64" offset=%d pte=0x%"PRIx64
 smmu_ptw_page_pte(int stage, int level,  uint64_t iova, uint64_t baseaddr, uint64_t pteaddr, uint64_t pte, uint64_t address) "stage=%d level=%d iova=0x%"PRIx64" base@=0x%"PRIx64" pte@=0x%"PRIx64" pte=0x%"PRIx64" page address = 0x%"PRIx64
 smmu_ptw_block_pte(int stage, int level, uint64_t baseaddr, uint64_t pteaddr, uint64_t pte, uint64_t iova, uint64_t gpa, int bsize_mb) "stage=%d level=%d base@=0x%"PRIx64" pte@=0x%"PRIx64" pte=0x%"PRIx64" iova=0x%"PRIx64" block address = 0x%"PRIx64" block size = %d MiB"
-smmu_get_pte(uint64_t baseaddr, int index, uint64_t pteaddr, uint64_t pte) "baseaddr=0x%"PRIx64" index=0x%x, pteaddr=0x%"PRIx64", pte=0x%"PRIx64
+smmu_get_pte(int sec_sid, uint64_t baseaddr, int index, uint64_t pteaddr, uint64_t pte) "sec_sid=%d baseaddr=0x%"PRIx64" index=0x%x, pteaddr=0x%"PRIx64", pte=0x%"PRIx64""
 smmu_iotlb_inv_all(void) "IOTLB invalidate all"
 smmu_iotlb_inv_asid_vmid(int asid, int vmid) "IOTLB invalidate asid=%d vmid=%d"
 smmu_iotlb_inv_vmid(int vmid) "IOTLB invalidate vmid=%d"
-- 
2.34.1
Re: [RFC v3 12/21] hw/arm/smmu-common: Implement secure state handling in ptw
Posted by Eric Auger 2 months, 1 week ago

On 10/12/25 5:12 PM, Tao Tang wrote:
> Enhance the page table walker to correctly handle secure and non-secure
> memory accesses. This change introduces logic to select the appropriate
> address space and enforce architectural security policies during walks.
>
> The page table walker now correctly processes Secure Stage 1
> translations. Key changes include:
>
> - The get_pte function now uses the security context to fetch table
> entries from either the Secure or Non-secure address space.
>
> - The stage 1 walker tracks the security state, respecting the NSCFG
> and NSTable attributes. It correctly handles the hierarchical security
> model: if a table descriptor in a secure walk has NSTable=1, all
> subsequent lookups for that walk are forced into the Non-secure space.
> This is a one-way transition, as specified by the architecture.
>
> - A check is added to fault nested translations that produce a Secure
> IPA when Secure stage 2 is not supported (SMMU_S_IDR1.SEL2 == 0).
>
> - The final TLB entry is tagged with the correct output address space,
> ensuring proper memory isolation.
>
> Stage 2 translations are currently limited to Non-secure lookups. Full
> support for Secure Stage 2 translation will be added in a future series.
>
> Signed-off-by: Tao Tang <tangtao1634@phytium.com.cn>
> ---
>  hw/arm/smmu-common.c | 64 +++++++++++++++++++++++++++++++++++++++-----
>  hw/arm/trace-events  |  2 +-
>  2 files changed, 59 insertions(+), 7 deletions(-)
>
> diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
> index 5fabe30c75..a092bb5a8d 100644
> --- a/hw/arm/smmu-common.c
> +++ b/hw/arm/smmu-common.c
> @@ -399,20 +399,26 @@ void smmu_iotlb_inv_vmid_s1(SMMUState *s, int vmid)
>   * @base_addr[@index]
>   */
>  static int get_pte(dma_addr_t baseaddr, uint32_t index, uint64_t *pte,
> -                   SMMUPTWEventInfo *info)
> +                   SMMUPTWEventInfo *info, SMMUSecSID sec_sid)
>  {
>      int ret;
>      dma_addr_t addr = baseaddr + index * sizeof(*pte);
> -
> +    MemTxAttrs attrs = smmu_get_txattrs(sec_sid);
> +    AddressSpace *as = smmu_get_address_space(sec_sid);
> +    if (!as) {
> +        info->type = SMMU_PTW_ERR_WALK_EABT;
is it WALK_EABT or PERMISSION in that case? I fail to find where it is
specified in the spec. Add a reference once?
> +        info->addr = addr;
> +        return -EINVAL;
> +    }
>      /* TODO: guarantee 64-bit single-copy atomicity */
> -    ret = ldq_le_dma(&address_space_memory, addr, pte, MEMTXATTRS_UNSPECIFIED);
> +    ret = ldq_le_dma(as, addr, pte, attrs);
>  
>      if (ret != MEMTX_OK) {
>          info->type = SMMU_PTW_ERR_WALK_EABT;
>          info->addr = addr;
>          return -EINVAL;
>      }
> -    trace_smmu_get_pte(baseaddr, index, addr, *pte);
> +    trace_smmu_get_pte(sec_sid, baseaddr, index, addr, *pte);
>      return 0;
>  }
>  
> @@ -543,6 +549,8 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
>  
>      baseaddr = extract64(tt->ttb, 0, cfg->oas);
>      baseaddr &= ~indexmask;
> +    int nscfg = tt->nscfg;
> +    bool forced_ns = false;  /* Track if NSTable=1 forced NS mode */
>  
>      while (level < VMSA_LEVELS) {
>          uint64_t subpage_size = 1ULL << level_shift(level, granule_sz);
> @@ -552,7 +560,10 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
>          dma_addr_t pte_addr = baseaddr + offset * sizeof(pte);
>          uint8_t ap;
>  
> -        if (get_pte(baseaddr, offset, &pte, info)) {
> +        /* Use NS if forced by previous NSTable=1 or current nscfg */
> +        int current_ns = forced_ns || nscfg;
> +        SMMUSecSID sec_sid = current_ns ? SMMU_SEC_SID_NS : SMMU_SEC_SID_S;
> +        if (get_pte(baseaddr, offset, &pte, info, sec_sid)) {
>                  goto error;
>          }
>          trace_smmu_ptw_level(stage, level, iova, subpage_size,
> @@ -577,6 +588,26 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
>                      goto error;
>                  }
>              }
> +
> +            /*
> +             * Hierarchical control of Secure/Non-secure accesses:
> +             * If NSTable=1 from Secure space, force all subsequent lookups to
> +             * Non-secure space and ignore future NSTable according to
> +             * (IHI 0070G.b)13.4.1 Stage 1 page permissions and
> +             * (DDI 0487H.a)D8.4.2 Control of Secure or Non-secure memory access
> +             */
> +            if (!forced_ns) {
> +                int new_nstable = PTE_NSTABLE(pte);
> +                if (!current_ns && new_nstable) {
> +                    /* First transition from Secure to Non-secure */
> +                    forced_ns = true;
> +                    nscfg = 1;
> +                } else if (!forced_ns) {
> +                    /* Still in original mode, update nscfg normally */
> +                    nscfg = new_nstable;
> +                }
> +                /* If forced_ns is already true, ignore NSTable bit */
> +            }
>              level++;
>              continue;
>          } else if (is_page_pte(pte, level)) {
> @@ -619,6 +650,13 @@ static int smmu_ptw_64_s1(SMMUState *bs, SMMUTransCfg *cfg,
>              goto error;
>          }
>  
> +        tlbe->sec_sid = PTE_NS(pte) ? SMMU_SEC_SID_NS : SMMU_SEC_SID_S;
> +        tlbe->entry.target_as = smmu_get_address_space(tlbe->sec_sid);
> +        if (!tlbe->entry.target_as) {
> +            info->type = SMMU_PTW_ERR_WALK_EABT;
> +            info->addr = gpa;
> +            goto error;
> +        }
>          tlbe->entry.translated_addr = gpa;
>          tlbe->entry.iova = iova & ~mask;
>          tlbe->entry.addr_mask = mask;
> @@ -688,7 +726,8 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
>          dma_addr_t pte_addr = baseaddr + offset * sizeof(pte);
>          uint8_t s2ap;
>  
> -        if (get_pte(baseaddr, offset, &pte, info)) {
> +        /* Use NS as Secure Stage 2 is not implemented (SMMU_S_IDR1.SEL2 == 0)*/
I don't really get this as you passed the sel2 in the cfg?
> +        if (get_pte(baseaddr, offset, &pte, info, SMMU_SEC_SID_NS)) {
>                  goto error;
>          }
>          trace_smmu_ptw_level(stage, level, ipa, subpage_size,
> @@ -741,6 +780,8 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
>              goto error_ipa;
>          }
>  
> +        tlbe->sec_sid = SMMU_SEC_SID_NS;
> +        tlbe->entry.target_as = &address_space_memory;
>          tlbe->entry.translated_addr = gpa;
>          tlbe->entry.iova = ipa & ~mask;
>          tlbe->entry.addr_mask = mask;
> @@ -825,6 +866,17 @@ int smmu_ptw(SMMUState *bs, SMMUTransCfg *cfg, dma_addr_t iova,
>          return ret;
>      }
>  
> +    if (!cfg->sel2 && tlbe->sec_sid > SMMU_SEC_SID_NS) {
> +        /*
> +         * Nested translation with Secure IPA output is not supported if
> +         * Secure Stage 2 is not implemented.
> +         */
> +        info->type = SMMU_PTW_ERR_TRANSLATION;
pointer to the spec for TRANSLATION error?

Otherwise looks good

Eric
> +        info->stage = SMMU_STAGE_1;
> +        tlbe->entry.perm = IOMMU_NONE;
> +        return -EINVAL;
> +    }
> +
>      ipa = CACHED_ENTRY_TO_ADDR(tlbe, iova);
>      ret = smmu_ptw_64_s2(cfg, ipa, perm, &tlbe_s2, info);
>      if (ret) {
> diff --git a/hw/arm/trace-events b/hw/arm/trace-events
> index 96ebd1b11b..a37e894766 100644
> --- a/hw/arm/trace-events
> +++ b/hw/arm/trace-events
> @@ -16,7 +16,7 @@ smmu_ptw_level(int stage, int level, uint64_t iova, size_t subpage_size, uint64_
>  smmu_ptw_invalid_pte(int stage, int level, uint64_t baseaddr, uint64_t pteaddr, uint32_t offset, uint64_t pte) "stage=%d level=%d base@=0x%"PRIx64" pte@=0x%"PRIx64" offset=%d pte=0x%"PRIx64
>  smmu_ptw_page_pte(int stage, int level,  uint64_t iova, uint64_t baseaddr, uint64_t pteaddr, uint64_t pte, uint64_t address) "stage=%d level=%d iova=0x%"PRIx64" base@=0x%"PRIx64" pte@=0x%"PRIx64" pte=0x%"PRIx64" page address = 0x%"PRIx64
>  smmu_ptw_block_pte(int stage, int level, uint64_t baseaddr, uint64_t pteaddr, uint64_t pte, uint64_t iova, uint64_t gpa, int bsize_mb) "stage=%d level=%d base@=0x%"PRIx64" pte@=0x%"PRIx64" pte=0x%"PRIx64" iova=0x%"PRIx64" block address = 0x%"PRIx64" block size = %d MiB"
> -smmu_get_pte(uint64_t baseaddr, int index, uint64_t pteaddr, uint64_t pte) "baseaddr=0x%"PRIx64" index=0x%x, pteaddr=0x%"PRIx64", pte=0x%"PRIx64
> +smmu_get_pte(int sec_sid, uint64_t baseaddr, int index, uint64_t pteaddr, uint64_t pte) "sec_sid=%d baseaddr=0x%"PRIx64" index=0x%x, pteaddr=0x%"PRIx64", pte=0x%"PRIx64""
>  smmu_iotlb_inv_all(void) "IOTLB invalidate all"
>  smmu_iotlb_inv_asid_vmid(int asid, int vmid) "IOTLB invalidate asid=%d vmid=%d"
>  smmu_iotlb_inv_vmid(int vmid) "IOTLB invalidate vmid=%d"
Re: [RFC v3 12/21] hw/arm/smmu-common: Implement secure state handling in ptw
Posted by Tao Tang 2 months, 1 week ago
Hi Eric,

On 2025/12/2 23:53, Eric Auger wrote:
>
> On 10/12/25 5:12 PM, Tao Tang wrote:
>> Enhance the page table walker to correctly handle secure and non-secure
>> memory accesses. This change introduces logic to select the appropriate
>> address space and enforce architectural security policies during walks.
>>
>> The page table walker now correctly processes Secure Stage 1
>> translations. Key changes include:
>>
>> - The get_pte function now uses the security context to fetch table
>> entries from either the Secure or Non-secure address space.
>>
>> - The stage 1 walker tracks the security state, respecting the NSCFG
>> and NSTable attributes. It correctly handles the hierarchical security
>> model: if a table descriptor in a secure walk has NSTable=1, all
>> subsequent lookups for that walk are forced into the Non-secure space.
>> This is a one-way transition, as specified by the architecture.
>>
>> - A check is added to fault nested translations that produce a Secure
>> IPA when Secure stage 2 is not supported (SMMU_S_IDR1.SEL2 == 0).
>>
>> - The final TLB entry is tagged with the correct output address space,
>> ensuring proper memory isolation.
>>
>> Stage 2 translations are currently limited to Non-secure lookups. Full
>> support for Secure Stage 2 translation will be added in a future series.
>>
>> Signed-off-by: Tao Tang <tangtao1634@phytium.com.cn>
>> ---
>>   hw/arm/smmu-common.c | 64 +++++++++++++++++++++++++++++++++++++++-----
>>   hw/arm/trace-events  |  2 +-
>>   2 files changed, 59 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
>> index 5fabe30c75..a092bb5a8d 100644
>> --- a/hw/arm/smmu-common.c
>> +++ b/hw/arm/smmu-common.c
>> @@ -399,20 +399,26 @@ void smmu_iotlb_inv_vmid_s1(SMMUState *s, int vmid)
>>    * @base_addr[@index]
>>    */
>>   static int get_pte(dma_addr_t baseaddr, uint32_t index, uint64_t *pte,
>> -                   SMMUPTWEventInfo *info)
>> +                   SMMUPTWEventInfo *info, SMMUSecSID sec_sid)
>>   {
>>       int ret;
>>       dma_addr_t addr = baseaddr + index * sizeof(*pte);
>> -
>> +    MemTxAttrs attrs = smmu_get_txattrs(sec_sid);
>> +    AddressSpace *as = smmu_get_address_space(sec_sid);
>> +    if (!as) {
>> +        info->type = SMMU_PTW_ERR_WALK_EABT;
> is it WALK_EABT or PERMISSION in that case? I fail to find where it is
> specified in the spec. Add a reference once?


Maybe this is the same situation I described earlier in the previous 
thread [1]?  I’m still not confident there is a clear architected 
mapping for this condition to a specific PTW event type. Rather than 
arbitrarily picking WALK_EABT or PERMISSION, I am leaning towards 
treating it as a pure model bug:

I’ll switch this to a g_assert(as) so we don’t report an architected 
event for something that should never happen on a correctly wired 
machine model.


[1] 
https://lore.kernel.org/qemu-devel/e80c6fbc-47a4-490a-8615-be2ee122eb94@phytium.com.cn/

>> +        info->addr = addr;
>> +        return -EINVAL;
>> +    }
>>       /* TODO: guarantee 64-bit single-copy atomicity */
>> -    ret = ldq_le_dma(&address_space_memory, addr, pte, MEMTXATTRS_UNSPECIFIED);
>> +    ret = ldq_le_dma(as, addr, pte, attrs);
>>   
>> ------------------------------<snip>------------------------------
>>
>>
>>
>> ------------------------------<snip>------------------------------
>>           tlbe->entry.translated_addr = gpa;
>>           tlbe->entry.iova = iova & ~mask;
>>           tlbe->entry.addr_mask = mask;
>> @@ -688,7 +726,8 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
>>           dma_addr_t pte_addr = baseaddr + offset * sizeof(pte);
>>           uint8_t s2ap;
>>   
>> -        if (get_pte(baseaddr, offset, &pte, info)) {
>> +        /* Use NS as Secure Stage 2 is not implemented (SMMU_S_IDR1.SEL2 == 0)*/
> I don't really get this as you passed the sel2 in the cfg?


In the next revision I’ll simplify the story. SMMUTransCfg will no 
longer carry a sel2 field, and this series will explicitly not support 
Secure Stage 2. In that context, the Stage-2 PTW will be hard-coded to 
use SMMU_SEC_SID_NS. If/when we add SEL2 support in a follow-up series, 
we can then make this driven by configuration instead of hard-coded.


>> +        if (get_pte(baseaddr, offset, &pte, info, SMMU_SEC_SID_NS)) {
>>                   goto error;
>>           }
>>           trace_smmu_ptw_level(stage, level, ipa, subpage_size,
>> @@ -741,6 +780,8 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
>>               goto error_ipa;
>>           }
>>   
>> +        tlbe->sec_sid = SMMU_SEC_SID_NS;
>> +        tlbe->entry.target_as = &address_space_memory;
>>           tlbe->entry.translated_addr = gpa;
>>           tlbe->entry.iova = ipa & ~mask;
>>           tlbe->entry.addr_mask = mask;
>> @@ -825,6 +866,17 @@ int smmu_ptw(SMMUState *bs, SMMUTransCfg *cfg, dma_addr_t iova,
>>           return ret;
>>       }
>>   
>> +    if (!cfg->sel2 && tlbe->sec_sid > SMMU_SEC_SID_NS) {
>> +        /*
>> +         * Nested translation with Secure IPA output is not supported if
>> +         * Secure Stage 2 is not implemented.
>> +         */
>> +        info->type = SMMU_PTW_ERR_TRANSLATION;
> pointer to the spec for TRANSLATION error?
>
> Otherwise looks good
>
> Eric


After re-reading the spec, I think we should move the check earlier, 
when decoding the STE/CD, and use the combination of SMMU_S_IDR1.SEL2, 
Config == 0b11x, and the Secure Stream table context to detect an 
architecturally illegal nested configuration.


In that case I’ll report a C_BAD_STE-style configuration error and bail 
out before running any Secure Stage-1 page walk. That both matches the 
spec more closely and avoids doing extra work in this unsupported 
configuration. How do you think about this?


Thanks again your review.

Tao