Re: [PATCH V4 04/19] machine: aux-ram-share option

[Steven Sistare <steven.sistare@oracle.com>]

On 12/9/2024 2:54 PM, Peter Xu wrote:
> On Mon, Dec 02, 2024 at 05:19:56AM -0800, Steve Sistare wrote:
>> diff --git a/system/physmem.c b/system/physmem.c
>> index 36f0811..0bcb2cc 100644
>> --- a/system/physmem.c
>> +++ b/system/physmem.c
>> @@ -2164,6 +2164,9 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
>>       new_block->flags = ram_flags;
>>   
>>       if (!host && !xen_enabled()) {
>> +        if (!share_flags && current_machine->aux_ram_share) {
>> +            new_block->flags |= RAM_SHARED;
>> +        }
> 
> Just to mention that if you agree with what I said in patch 2, here it will
> need some trivial rebase change.  IOW, IMO we shouldn't special case xen
> either here, so it should also apply to xen if one chose to, changing aux
> alloc to RAM_SHARED.

OK.

So, if this only requires a trivial change, do I get your RB?

- Steve
> 
> Frankly I don't know whether xen respects RAM_SHARED at all for anonymous,
> but it's a separate question to ask..
> 
> Basically what will happen later is in cpr-transfer migrate cmd, it'll fail
> for xen properly seeing fd==-1.  That'll be fine, IMHO.
> 
>>           if ((new_block->flags & RAM_SHARED) &&
>>               !qemu_ram_alloc_shared(new_block, &local_err)) {
>>               goto err;
> 
> 
>