Shared memory between host and guest

Shared memory between host and guest

[Lu, Jingdong]

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Hi experts,

I have some basic questions regarding shared memory between host and guest based on QEMU/KVM:

1, Can host and guest share the same block of physical memory? Ivshmem? Is it continuous physical memory?

2, More specifically, is there any way to support the following operations?

  1.  Guest starts.
  2.  Host side allocates one block of physical memory like 2MB.
  3.  Host side adds this memory to running guest  memory mapping.
  4.  Both of host and guest can access this shared memory.

Best Regards,
Jingdong

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Re: Shared memory between host and guest

[Alex Bennée]

"Lu, Jingdong" <jingdong.lu@intel.com> writes:

> Hi experts,
>
>  
>
> I have some basic questions regarding shared memory between host and guest based on QEMU/KVM:
>
>  
>
> 1, Can host and guest share the same block of physical memory? Ivshmem? Is it continuous physical memory?
>
>  
>
> 2, More specifically, is there any way to support the following operations?
>
> 1 Guest starts.
>
> 2 Host side allocates one block of physical memory like 2MB.
>
> 3 Host side adds this memory to running guest  memory mapping.

With support for pci hotplug you can add/remove virtio-pmem blocks to
the guest.

>
> 4 Both of host and guest can access this shared memory.

Yes - you can back the memory with a file. See:

  https://qemu.readthedocs.io/en/latest/system/devices/virtio-pmem.html


>
>  
>
> Best Regards,
>
> Jingdong


-- 
Alex Bennée