Re: [PATCH v3 08/13] migration/ram: Simplify host page handling in ram_load_postcopy()

[David Hildenbrand <david@redhat.com>]

On 06.03.20 17:20, David Hildenbrand wrote:
> On 06.03.20 17:05, Dr. David Alan Gilbert wrote:
>> * David Hildenbrand (david@redhat.com) wrote:
>>> Add two new helper functions. This will in come handy once we want to
>>> handle ram block resizes while postcopy is active.
>>>
>>> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>>> Cc: Juan Quintela <quintela@redhat.com>
>>> Cc: Peter Xu <peterx@redhat.com>
>>> Signed-off-by: David Hildenbrand <david@redhat.com>
>>> ---
>>>  migration/ram.c | 54 ++++++++++++++++++++++++++++---------------------
>>>  1 file changed, 31 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/migration/ram.c b/migration/ram.c
>>> index d5a4d69e1c..f815f4e532 100644
>>> --- a/migration/ram.c
>>> +++ b/migration/ram.c
>>> @@ -2734,6 +2734,20 @@ static inline void *host_from_ram_block_offset(RAMBlock *block,
>>>      return block->host + offset;
>>>  }
>>>  
>>> +static void *host_page_from_ram_block_offset(RAMBlock *block,
>>> +                                             ram_addr_t offset)
>>> +{
>>> +    /* Note: Explicitly no check against offset_in_ramblock(). */
>>> +    return (void *)QEMU_ALIGN_DOWN((uintptr_t)block->host + offset,
>>> +                                   block->page_size);
>>> +}
>>> +
>>> +static ram_addr_t host_page_offset_from_ram_block_offset(RAMBlock *block,
>>> +                                                         ram_addr_t offset)
>>> +{
>>> +    return ((uintptr_t)block->host + offset) & (block->page_size - 1);
>>> +}
>>> +
>>>  static inline void *colo_cache_from_block_offset(RAMBlock *block,
>>>                                                   ram_addr_t offset)
>>>  {
>>> @@ -3111,13 +3125,12 @@ static int ram_load_postcopy(QEMUFile *f)
>>>      MigrationIncomingState *mis = migration_incoming_get_current();
>>>      /* Temporary page that is later 'placed' */
>>>      void *postcopy_host_page = mis->postcopy_tmp_page;
>>> -    void *this_host = NULL;
>>> +    void *host_page = NULL;
>>>      bool all_zero = false;
>>>      int target_pages = 0;
>>>  
>>>      while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
>>>          ram_addr_t addr;
>>> -        void *host = NULL;
>>>          void *page_buffer = NULL;
>>>          void *place_source = NULL;
>>>          RAMBlock *block = NULL;
>>> @@ -3143,9 +3156,12 @@ static int ram_load_postcopy(QEMUFile *f)
>>>          if (flags & (RAM_SAVE_FLAG_ZERO | RAM_SAVE_FLAG_PAGE |
>>>                       RAM_SAVE_FLAG_COMPRESS_PAGE)) {
>>>              block = ram_block_from_stream(f, flags);
>>> +            if (!block) {
>>> +                ret = -EINVAL;
>>
>> Could we have an error_report there, at the moment it would trigger
>> the one below.
> 
> Makes sense, I'll add one!

My memory kicks in: This was dropped on purpose. ram_block_from_stream()
will print proper errors already.

Cheers!


-- 
Thanks,

David / dhildenb