Re: [PATCH v2 4/5] powerpc/pseries: Implement RTAS error injection via pseries_eeh_err_inject

[Narayana Murty N <nnmlinux@linux.ibm.com>]

Hi Sourabh,
On 10/06/26 9:15 AM, Sourabh Jain wrote:
>
>
> On 27/05/26 12:54, Narayana Murty N wrote:
>> Replace legacy MMIO error injection with full PAPR-compliant RTAS error
>> injection supporting 14+ error types via
>>   - ibm,open-errinjct
>>   - ibm,errinjct
>>   - ibm,close-errinjct.
>>
>> Key features:
>> - Complete open-session-inject-close cycle management
>> - Special handling for ibm,open-errinjct output format (token,status)
>> - Comprehensive buffer preparation per PAPR layouts
>> - All pr_* logging uses pr_fmt("EEH: ") prefix
>>
>> Tested with corresponding QEMU patches:
>> https://lore.kernel.org/all/20251029150618.186803-1-nnmlinux@linux.ibm.com/ 
>>
>>
>> Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com>
>> ---
>>   arch/powerpc/platforms/pseries/eeh_pseries.c | 168 ++++++++++++++++---
>>   1 file changed, 147 insertions(+), 21 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c 
>> b/arch/powerpc/platforms/pseries/eeh_pseries.c
>> index d6f2e0d43b89..6af2a153ec25 100644
>> --- a/arch/powerpc/platforms/pseries/eeh_pseries.c
>> +++ b/arch/powerpc/platforms/pseries/eeh_pseries.c
>> @@ -902,8 +902,7 @@ static int validate_special_event(unsigned long 
>> addr, unsigned long mask)
>>    * Return: 0 if valid, RTAS_INVALID_PARAMETER otherwise.
>>    */
>>   -static int validate_corrupted_page(struct eeh_pe *pe __maybe_unused,
>> -                   unsigned long addr, unsigned long mask)
>> +static int validate_corrupted_page(unsigned long addr, unsigned long 
>> mask)
>>   {
>>       if (!addr) {
>>           pr_err("corrupted-page requires non-zero addr\n");
>> @@ -978,7 +977,7 @@ static int prepare_errinjct_buffer(struct eeh_pe 
>> *pe, int type, int func,
>>           if (addr == 0)
>>               return RTAS_INVALID_PARAMETER;
>>   -        if (validate_corrupted_page(pe, addr, mask))
>> +        if (validate_corrupted_page(addr, mask))
>>               return RTAS_INVALID_PARAMETER;
>>             buf32[0] = cpu_to_be32(upper_32_bits(addr));
>> @@ -1047,6 +1046,97 @@ static int prepare_errinjct_buffer(struct 
>> eeh_pe *pe, int type, int func,
>>       return 0;
>>   }
>>   +/**
>> + * rtas_open_errinjct_session - Open an RTAS error injection session
>> + *
>> + * Opens a session with the RTAS ibm,open-errinjct service.
>> + *
>> + * Return: Positive session token on success, negative error code on 
>> failure.
>> + */
>> +static int rtas_open_errinjct_session(void)
>> +{
>> +    int open_token, args[2] = {0};
>> +    int rc, status, session_token = -1;
>> +
>> +    open_token = rtas_function_token(RTAS_FN_IBM_OPEN_ERRINJCT);
>> +    if (open_token == RTAS_UNKNOWN_SERVICE) {
>> +        pr_err("RTAS: ibm,open-errinjct not available\n");
>> +        return RTAS_UNKNOWN_SERVICE;
>> +    }
>> +
>> +    /* Call open; original code treated rtas_call return as session 
>> token */
>> +    rc = rtas_call(open_token, 0, 2, args);
>> +    status = args[1];
>> +    if (status != 0) {
>> +        pr_err("RTAS: open-errinjct failed: status=%d args[1]=%d 
>> rc=%d\n",
>> +               status, args[1], rc);
>> +        return status ? status : -EIO;
>> +    }
>> +
>> +    session_token = args[0];
>> +    pr_info("Opened injection session: token=%d\n", session_token);
>> +    return session_token;
>> +}
>> +
>> +/**
>> + * rtas_close_errinjct_session - Close an RTAS error injection session
>> + * @session_token: Session token returned from open
>> + *
>> + * Attempts to close a previously opened error injection session. 
>> Best-effort;
>> + * logs warnings if close fails or if service is unavailable.
>> + */
>> +
>> +static void rtas_close_errinjct_session(int session_token)
>> +{
>> +    int close_token, args[2] = {0};
>> +
>> +    if (session_token <= 0)
>> +        return;
>> +
>> +    close_token = rtas_function_token(RTAS_FN_IBM_CLOSE_ERRINJCT);
>> +    if (close_token == RTAS_UNKNOWN_SERVICE) {
>> +        pr_warn("close-errinjct not available\n");
>> +        return;
>> +    }
>> +
>> +    args[0] = session_token;
>> +    rtas_call(close_token, 1, 1, args);
>> +    if (args[0])
>> +        pr_warn("close-errinjct  args[0]=%d\n", args[0]);
>> +}
>> +
>> +/**
>> + * do_errinjct_call - Invoke the RTAS error injection service
>> + * @errinjct_token: RTAS token for ibm,errinjct
>> + * @type:           RTAS error type
>> + * @session_token:  RTAS error injection session token
>> + *
>> + * Issues the RTAS ibm,errinjct call with the prepared work buffer. 
>> Logs errors
>> + * on failure.
>> + *
>> + * Return: 0 on success, negative error code otherwise.
>> + */
>> +
>> +static int do_errinjct_call(int errinjct_token, int type, int 
>> session_token)
>> +{
>> +    int rc, status;
>> +
>> +    if (errinjct_token == RTAS_UNKNOWN_SERVICE)
>> +        return -ENODEV;
>> +
>> +    /* errinjct takes: type, session_token, workbuf pointer (3 in), 
>> returns status */
>> +    rc = rtas_call(errinjct_token, 3, 1, &status, type, session_token,
>> +               rtas_errinjct_buf);
>
> Why are we passing virtual address of rtas_errinjct_buf (working 
> buffer address) to rtas call?

You are right. |ibm,errinjct|expects the physical address of the RTAS 
work buffer.
Passing the kernel virtual address of |rtas_errinjct_buf|here was incorrect.
This has been fixed in v3. The error-injection buffer is allocated in an
RTAS-accessible RMO region, and the physical address of the buffer is passed
to |ibm,errinjct|. The virtual address is used only by the kernel while 
preparing the buffer contents.


Thanks,
Narayana
>
>> +
>> +    if (rc || status != 0) {
>> +        pr_err("RTAS: errinjct failed: rc=%d, status=%d\n", rc, 
>> status);
>> +        return status ? status : -EIO;
>> +    }
>> +
>> +    pr_info("RTAS: errinjct ok: rc=%d, status=%d\n", rc, status);
>> +    return 0;
>> +}
>> +
>>   /**
>>    * pseries_eeh_err_inject - Inject specified error to the indicated PE
>>    * @pe: the indicated PE
>> @@ -1060,30 +1150,66 @@ static int prepare_errinjct_buffer(struct 
>> eeh_pe *pe, int type, int func,
>>   static int pseries_eeh_err_inject(struct eeh_pe *pe, int type, int 
>> func,
>>                     unsigned long addr, unsigned long mask)
>>   {
>> -    struct    eeh_dev    *pdev;
>> +    int rc = 0;
>> +    int session_token = -1;
>> +    int errinjct_token;
>>   -    /* Check on PCI error type */
>> -    if (type != EEH_ERR_TYPE_32 && type != EEH_ERR_TYPE_64)
>> -        return -EINVAL;
>> +    /* Validate type */
>> +    if (!validate_err_type(type)) {
>> +        pr_err("RTAS: invalid error type 0x%x\n", type);
>> +        return RTAS_INVALID_PARAMETER;
>> +    }
>> +    pr_debug("RTAS: error type 0x%x\n", type);
>>   -    switch (func) {
>> -    case EEH_ERR_FUNC_LD_MEM_ADDR:
>> -    case EEH_ERR_FUNC_LD_MEM_DATA:
>> -    case EEH_ERR_FUNC_ST_MEM_ADDR:
>> -    case EEH_ERR_FUNC_ST_MEM_DATA:
>> -        /* injects a MMIO error for all pdev's belonging to PE */
>> -        pci_lock_rescan_remove();
>> -        list_for_each_entry(pdev, &pe->edevs, entry)
>> -            eeh_pe_inject_mmio_error(pdev->pdev);
>> -        pci_unlock_rescan_remove();
>> -        break;
>> -    default:
>> -        return -ERANGE;
>> +    /* For IOA bus errors we must validate err_func and addr/mask in 
>> PE.
>> +     * For other types: if addr/mask present we'll still validate 
>> BAR range;
>> +     * otherwise skip function checks.
>> +     */
>> +    if (type == RTAS_ERR_TYPE_IOA_BUS_ERROR ||
>> +        type == RTAS_ERR_TYPE_IOA_BUS_ERROR_64) {
>> +        /* Validate that addr/mask fall in the PE's BAR ranges */
>> +        rc = validate_addr_mask_in_pe(pe, addr, mask);
>> +        if (rc)
>> +            return rc;
>> +    } else if (addr || mask) {
>> +        /* If caller provided addr/mask for a non-IOA type, do a BAR 
>> check too */
>> +        rc = validate_addr_mask_in_pe(pe, addr, mask);
>> +        if (rc)
>> +            return rc;
>>       }
>>   -    return 0;
>> +    /* Open RTAS session */
>> +    session_token = rtas_open_errinjct_session();
>> +    if (session_token < 0)
>> +        return session_token;
>> +
>> +    /* get errinjct token */
>> +    errinjct_token = rtas_function_token(RTAS_FN_IBM_ERRINJCT);
>> +    if (errinjct_token == RTAS_UNKNOWN_SERVICE) {
>> +        pr_err("RTAS: ibm,errinjct not available\n");
>> +        rc = -ENODEV;
>> +        goto out_close;
>> +    }
>> +
>> +    /* prepare shared buffer while holding lock */
>> +    spin_lock(&rtas_errinjct_buf_lock);
>> +    rc = prepare_errinjct_buffer(pe, type, func, addr, mask);
>> +    if (rc) {
>> +        spin_unlock(&rtas_errinjct_buf_lock);
>> +        goto out_close;
>> +    }
>> +
>> +    /* perform the errinjct RTAS call */
>> +    rc = do_errinjct_call(errinjct_token, type, session_token);
>> +    spin_unlock(&rtas_errinjct_buf_lock);
>> +
>> +out_close:
>> +    /* always attempt close if we opened a session */
>> +    rtas_close_errinjct_session(session_token);
>> +    return rc;
>>   }
>>   +
>>   static struct eeh_ops pseries_eeh_ops = {
>>       .name            = "pseries",
>>       .probe            = pseries_eeh_probe,
>