Re: [Qemu-devel] [PATCH V8 1/4] mem: add share parameter to memory-backend-ram

[Eduardo Habkost <ehabkost@redhat.com>]

On Wed, Jan 17, 2018 at 11:54:18AM +0200, Marcel Apfelbaum wrote:
> Currently only file backed memory backend can
> be created with a "share" flag in order to allow
> sharing guest RAM with other processes in the host.
> 
> Add the "share" flag also to RAM Memory Backend
> in order to allow remapping parts of the guest RAM
> to different host virtual addresses. This is needed
> by the RDMA devices in order to remap non-contiguous
> QEMU virtual addresses to a contiguous virtual address range.
> 

Why do we need to make this configurable?  Would anything break
if MAP_SHARED was always used if possible?


> Moved the "share" flag to the Host Memory base class,
> modified phys_mem_alloc to include the new parameter
> and a new interface memory_region_init_ram_shared_nomigrate.
> 
> There are no functional changes if the new flag is not used.
> 
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
[...]

-- 
Eduardo