diff options
| author | Marcel Apfelbaum <marcel@redhat.com> | 2017-12-13 16:37:37 +0200 |
|---|---|---|
| committer | Marcel Apfelbaum <marcel@redhat.com> | 2018-02-19 13:03:24 +0200 |
| commit | 06329ccecfa022494fdba288b3ab5bcb8dff4159 (patch) | |
| tree | 6ac05bd91e27d422a5e7d4e1804d626f17216e8e /qemu-options.hx | |
| parent | e5ecc287a7bd24a1364e23e263cb60cfc8d21eb5 (diff) | |
mem: add share parameter to memory-backend-ram
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.
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.
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Diffstat (limited to 'qemu-options.hx')
| -rw-r--r-- | qemu-options.hx | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/qemu-options.hx b/qemu-options.hx index 5050a49a5e..8ccd5dcaa6 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3975,6 +3975,14 @@ The @option{share} boolean option determines whether the memory region is marked as private to QEMU, or shared. The latter allows a co-operating external process to access the QEMU memory region. +The @option{share} is also required for pvrdma devices due to +limitations in the RDMA API provided by Linux. + +Setting share=on might affect the ability to configure NUMA +bindings for the memory backend under some circumstances, see +Documentation/vm/numa_memory_policy.txt on the Linux kernel +source tree for additional details. + Setting the @option{discard-data} boolean option to @var{on} indicates that file contents can be destroyed when QEMU exits, to avoid unnecessarily flushing data to the backing file. Note @@ -4017,7 +4025,7 @@ requires an alignment different than the default one used by QEMU, eg the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In such cases, users can specify the required alignment via this option. -@item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave} +@item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave} Creates a memory backend object, which can be used to back the guest RAM. Memory backend objects offer more control than the @option{-m} option that is |