Hi Suravee,

On Wed, Mar 27, 2013 at 06:51:23PM -0500, suravee.suthikulpa...@amd.com wrote:
> From: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
> 
> Add logic to decode AMD IOMMU event flag based on information from AMD IOMMU 
> specification.
> This should simplify debugging IOMMU errors.  Also, dump DTE information in 
> additional cases.

The patch in general makes sense to have, but I have a couple of
comments.

> +static void dump_flags(int flags, int ev_type)
> +{
> +     struct _event_log_flags *p = (struct _event_log_flags *) &flags;
> +     u32 err_type = p->type;
> +
> +     pr_err("AMD-Vi: Flags details:\n");
> +     pr_err("AMD-Vi:    Guest / Nested  : %u\n", p->gn);
> +     pr_err("AMD-Vi:    No Execute      : %u\n", p->nx);
> +     pr_err("AMD-Vi:    User-Supervisor : %u\n", p->us);
> +     pr_err("AMD-Vi:    Interrupt       : %u\n", p->i);
> +     pr_err("AMD-Vi:    Present         : %u\n", p->pr);
> +     pr_err("AMD-Vi:    Read / Write    : %u\n", p->rw);
> +     pr_err("AMD-Vi:    Permission      : %u\n", p->pe);
> +     pr_err("AMD-Vi:    Reserv bit not zero / Illegal level encoding : %u\n",
> +             p->rz);
> +     pr_err("AMD-Vi:    Translation / Transaction : %u\n",
> +             p->tr);
> +     pr_err("AMD-Vi:    Type of error   : (0x%x) ", err_type);

Printing the flags multi-line is much too noisy for IOMMU events. Just
print a char-shortcut for each flag set on the same line.

> +
> +     if ((ev_type == EVENT_TYPE_DEV_TAB_ERR)  ||
> +         (ev_type == EVENT_TYPE_PAGE_TAB_ERR) ||
> +         (ev_type == EVENT_TYPE_CMD_HARD_ERR)) {
> +             /* Only supports up to 2 bits */
> +             err_type &= 0x3;
> +             switch (err_type) {
> +             case 0:
> +                     pr_err("Reserved\n");
> +                     break;
> +             case 1:
> +                     pr_err("Master Abort\n");
> +                     break;
> +             case 2:
> +                     pr_err("Target Abort\n");
> +                     break;
> +             case 3:
> +                     pr_err("Data Error\n");
> +                     break;
> +             }

Why do you create string-arrays for other type-encodings but not for
this one?

> +     } else if (ev_type == EVENT_TYPE_INV_DEV_REQ) {
> +             if (p->tr == 0) {
> +                     if (err_type < ARRAY_SIZE(_invalid_translation_desc))
> +                             printk("%s\n",
> +                                     _invalid_translation_desc[err_type]);
> +             } else {
> +                     if (err_type < ARRAY_SIZE(_invalid_transaction_desc))
> +                             printk("%s\n",
> +                                     _invalid_transaction_desc[err_type]);

pr_cont instead of printk.


        Joerg


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