Re: [RFC v5 00/86] Memory API

Jan Kiszka
2011-07-21T13:38:44Z

On 2011-07-21 10:37, Avi Kivity wrote:
> On 07/21/2011 12:43 AM, Jan Kiszka wrote:
>> On 2011-07-20 19:43, Avi Kivity wrote:
>> > On 07/20/2011 08:41 PM, Jan Kiszka wrote:
>> >> On 2011-07-20 18:49, Avi Kivity wrote:
>> >> > New in this version:
>> >> > - more mindless conversions; I believe there are no longer any
>> >> destructive
>> >> > operations in the tree (IO_MEM_UNASSIGNED)
>> >> > - fix memory map generation bug (patch 13)
>> >> > - proper 440FX PAM/SMRAM and PCI holes
>> >> >
>> >>
>> >> This on top fixes standard VGA dirty logging:
>> >
>> > Both work for me without any patches.
>>
>> Impossible! ;)
>>
>> VGA frame buffer cannot work as no one enabled dirty logging for that
>> range so far. Try -vga std with vga=0x314 in the guest.
>>
>
> Right, actually booting into X showed that. But I don't understand how
> it worked before - my patches only change how vga_start_dirty_log() is
> implemented, not when/where it is called.

To answer this question as well: You dropped all the vga_start_dirty_log
originally performed during PCI mapping.

>
>
>> >
>> > Maybe the F15 window manager is polling the display?
>> >
>>
>> Only if that continuously enforces a full window refresh.
>
> Turned out to be a tester issue.
>
>> As expected, there were dirty logging issues around removing a
>> subregion on cirrus bank pointer updates. This makes linear vram
>> mappings work again:
>
> Please sign off patches!

Always - once they are done.

>
>> diff --git a/memory.c b/memory.c
>> index a8d4295..14fac8a 100644
>> --- a/memory.c
>> +++ b/memory.c
>> @@ -1093,9 +1093,26 @@ void
>> memory_region_add_subregion_overlap(MemoryRegion *mr,
>> void memory_region_del_subregion(MemoryRegion *mr,
>> MemoryRegion *subregion)
>> {
>> + MemoryRegion *target_region;
>> + ram_addr_t base, offs;
>> +
>> assert(subregion->parent == mr);
>> subregion->parent = NULL;
>> QTAILQ_REMOVE(&mr->subregions, subregion, subregions_link);
>> +
>> + if (subregion->alias) {
>> + base = subregion->alias_offset;
>> + target_region = subregion->alias;
>> + } else {
>> + base = 0;
>> + target_region = subregion;
>> + }
>> + if (target_region->dirty_log_mask) {
>> + for (offs = 0; offs< subregion->size; offs +=
>> TARGET_PAGE_SIZE) {
>> + memory_region_set_dirty(target_region, base + offs);
>> + }
>> + }
>> +
>
> The subregion may be partially or fully obstructed. This needs to be
> done at the FlatRange level (as_memory_range_del(), most likely).

Makes some sense. I even wonder if this isn't a KVM deficit and should
be handled there when a logged region is unmapped.

Jan

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