Re: [PATCH v2 1/2] ram-block-attributes: Avoid the overkill of shared memory with hugetlbfs backend

[Peter Xu <peterx@redhat.com>]

On Thu, Oct 23, 2025 at 12:16:46PM +0200, David Hildenbrand wrote:
> On 23.10.25 11:55, Chenyi Qiang wrote:
> 
> Subject should probably rather be:
> 
> "ram-block-attributes: fix interaction with hugetlb memory backends"
> 
> Maybe that can be fixed up when applying.

I also agree the old subject is slightly confusing..

I queued the two patches with all the small fixups.

Thanks,

> 
> > Currently, CoCo VMs can perform conversion at the base page granularity,
> > which is the granularity that has to be tracked. In relevant setups, the
> > target page size is assumed to be equal to the host page size, thus
> > fixing the block size to the host page size.
> > 
> > However, since private memory and shared memory have different backend
> > at present, users can specify shared memory with a hugetlbfs backend
> > while private memory with guest_memfd backend only supports 4K page
> > size. In this scenario, ram_block->page_size is different from the host
> > page size which will trigger an assertion when retrieving the block
> > size.
> > 
> > To address this, return the host page size directly to relax the
> > restriction. This changes fixes a regression of using hugetlbfs backend
> > for shared memory within CoCo VMs, with or without VFIO devices' presence.
> > 
> > Acked-by: David Hildenbrand <david@redhat.com>
> > Tested-by: Farrah Chen <farrah.chen@intel.com>
> > Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
> > ---
> 
> 
> -- 
> Cheers
> 
> David / dhildenb
> 

-- 
Peter Xu