Re: [PATCH v1 0/3] virtio-mem: Support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE

[David Hildenbrand <david@redhat.com>]

On 01.12.21 00:45, Michael S. Tsirkin wrote:
> On Tue, Nov 30, 2021 at 10:28:35AM +0100, David Hildenbrand wrote:
>> Support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE in QEMU, which indicates to
>> a guest that we don't support reading unplugged memory. We indicate
>> the feature based on a new "unplugged-inaccessible" property available
>> for x86 targets only (the only ones with legacy guests). Guests that don't
>> support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE will fail initialization if
>> indicated/required by the hypervisor.
>>
>> For example, Linux guests starting with v5.16 will support
>> VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE.
>>
>> For future targets that don't have legacy guests (especially arm64), we'll
>> always indicate VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE.
>>
>> More details can be found in the description of patch #2.
>>
>> "
>> For existing compat machines, the property will default to "off", to
>> not change the behavior but eventually warn about a problematic setup.
>> Short-term, we'll set the property default to "auto" for new QEMU machines.
>> Mid-term, we'll set the property default to "on" for new QEMU machines.
>> Long-term, we'll deprecate the parameter and disallow legacy guests
>> completely.
>> "
>>
>> TODO: Once 6.2 was release, adjust patch #3. Replace patch #1 by a proper
>>       Linux header sync.
> 
> 
> oh so it's not for 6.2. got it.

It would be awesome to get it into 6.2 (!), but I assume that ship has
sailed, right?


-- 
Thanks,

David / dhildenb