On 05.06.2025 11:13, Oleksii Kurochko wrote:
>
> On 6/5/25 8:50 AM, Jan Beulich wrote:
>> On 04.06.2025 17:36, Oleksii Kurochko wrote:
>>> On 6/2/25 12:21 PM, Jan Beulich wrote:
>>>> On 26.05.2025 20:44, Oleksii Kurochko wrote:
>>>>> On 5/22/25 4:46 PM, Jan Beulich wrote:
>>>>>> On 21.05.2025 18:03, Oleksii Kurochko wrote:
>>>>>>> + /* Check MMIO register sets */
>>>>>>> + for ( unsigned int i = 0; i < nr_mmios; i++ )
>>>>>>> + {
>>>>>>> + if ( !alloc_cpumask_var(&imsic_cfg.mmios[i].cpus) )
>>>>>>> + {
>>>>>>> + rc = -ENOMEM;
>>>>>>> + goto imsic_init_err;
>>>>>>> + }
>>>>>>> +
>>>>>>> + rc = dt_device_get_address(node, i,
>>>>>>> &imsic_cfg.mmios[i].base_addr,
>>>>>>> + &imsic_cfg.mmios[i].size);
>>>>>>> + if ( rc )
>>>>>>> + {
>>>>>>> + printk(XENLOG_ERR "%s: unable to parse MMIO regset %u\n",
>>>>>>> + node->name, i);
>>>>>>> + goto imsic_init_err;
>>>>>>> + }
>>>>>>> +
>>>>>>> + base_addr = imsic_cfg.mmios[i].base_addr;
>>>>>>> + base_addr &= ~(BIT(imsic_cfg.guest_index_bits +
>>>>>>> + imsic_cfg.hart_index_bits +
>>>>>>> + IMSIC_MMIO_PAGE_SHIFT, UL) - 1);
>>>>>>> + base_addr &= ~((BIT(imsic_cfg.group_index_bits, UL) - 1) <<
>>>>>>> + imsic_cfg.group_index_shift);
>>>>>>> + if ( base_addr != imsic_cfg.base_addr )
>>>>>>> + {
>>>>>>> + rc = -EINVAL;
>>>>>>> + printk(XENLOG_ERR "%s: address mismatch for regset %u\n",
>>>>>>> + node->name, i);
>>>>>>> + goto imsic_init_err;
>>>>>>> + }
>>>>>> Maybe just for my own understanding: There's no similar check for the
>>>>>> sizes to match / be consistent wanted / needed?
>>>>> If you are speaking about imsic_cfg.mmios[i].size then it depends fully
>>>>> on h/w will
>>>>> provide, IMO.
>>>>> So I don't what is possible range for imsic_cfg.mmios[i].size.
>>>> Well, all I can say is that's it feels odd that you sanity check base_addr
>>>> but permit effectively any size.
>>> Okay, I think I have two ideas how to check the size:
>>> 1. Based on guest bits from IMSIC's DT node. QEMU calculates a size as:
>>> for (socket = 0; socket < socket_count; socket++) {
>>> imsic_addr = base_addr + socket * VIRT_IMSIC_GROUP_MAX_SIZE;
>>> imsic_size = IMSIC_HART_SIZE(imsic_guest_bits) *
>>> s->soc[socket].num_harts;
>>> ...
>>> where:
>>> #define IMSIC_MMIO_PAGE_SHIFT 12
>>> #define IMSIC_MMIO_PAGE_SZ (1UL << IMSIC_MMIO_PAGE_SHIFT)
>>>
>>> #define IMSIC_HART_NUM_GUESTS(__guest_bits) \
>>> (1U << (__guest_bits))
>>> #define IMSIC_HART_SIZE(__guest_bits) \
>>> (IMSIC_HART_NUM_GUESTS(__guest_bits) * IMSIC_MMIO_PAGE_SZ)
>>>
>>> 2. Just take a theoretical maximum for S-mode IMSIC's node:
>>> 16,384 * 64 1(S-mode interrupt file) + 63(max guest interrupt files))
>>> * 4 KiB
>>> Where,
>>> 16,384 - maximum possible amount of harts according to AIA spec
>>> 64 - a maximum amount of possible interrupt file for S-mode IMSIC
>>> node:
>>> 1 - S interupt file + 63 guest interrupt files.
>>> 4 Kib - a maximum size of one interrupt file.
>>>
>>> Which option is preferred?
>> I would have said 2, if your outline used "actual" rather than "maximum"
>> values.
>
> In option 2 maximum possible values are used. If we want to use "actual"
> values then
> the option 1 should be used.
Actually I was wrong with request "actual" uniformly. It's only the hart count
where
I meant to ask for that. For interrupts we should allow the maximum possible
unless
we already know their count.
Jan
