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

[David Hildenbrand <david@redhat.com>]

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.

> 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