Support Tiers

Note this article is a draft / work in progress / scratch-pad.

It is not official project policy at this time.

Definitions

QEMU features are classified into a number of support tiers, which serve as guidance to users on the long term intentions wrt quality and supportability.

Tier 1

These are the top class features, suitable for use in a virtualization scenario and expected to be fully functional at all times.

MUST be built by automated CI systems prior to merge

MUST be tested by automated CI systems prior to merge

MUST be written to be robust against malicious guests

MUST have a nominated subsystem maintainer

Tier 2

These are generally good features, but have some caveats preventing them achieving the top tier. They may only be suitable for use in an emulation scenario and may not be functional except at time of release.

MUST be built by automated CI systems prior to merge

MAY NOT be tested by automated CI systems prior to merge

SHOULD be tested manually by maintainer prior to major releases

MAY NOT be written to be robust against malicious guests

MUST have a nominated subsystem maintainer

Tier 3

These features are generally not recommended to be used. They may be insecure and can be non-functional at any time, even in releases. They are liable to be removed entirely at any time.

MAY NOT be tested by automated CI systems prior to merge

MAY NOT be tested manually by maintainer prior to major releases

MAY NOT be written to be robust against malicious guests

MAY NOT have a nominated subsystem maintainer

Host architectures

Arch	Tier	Comments
armv7	1	-
aarch64	1	-
i686	1	-
mips	2	-
mips64	2	-
ppc	2	-
ppc64	1	-
riscv32	2	-
riscv64	2	-
s390	3	-
s390x	1	-
x86_64	1	-

Networking

Virtualizer	Arch	Tier	Comments
KVM	arm7	1
KVM	aarch64	1
KVM	i686	1
KVM	mips	2
KVM	mips64	2
KVM	ppc	2
KVM	ppc64	1
KVM	s390x	1
KVM	x86_64	1
Hax	x86_64	2
HyperV	x86_64	2
WHPX	x86_64	2
HVF	x86_64	2