This series makes it possible to enable MTE for kvm guests, if the kernel supports it. Again, tested on the simulator via patiently waiting for the arm64/mte kselftests to finish successfully. For tcg, turning on mte on the machine level (to get tag memory) stays a requirement. If the new mte cpu feature is not explicitly specified, a tcg vm will get mte depending on the presence of tag memory (just as today). For kvm, mte stays off by default; this is because migration is not yet supported (postcopy will need an extension of the kernel interface, possibly an extension of the userfaultfd interface), and turning on mte will add a migration blocker. My biggest question going forward is actually concerning migration; I gather that we should not bother adding something unless postcopy is working as well? If I'm not misunderstanding things, we need a way to fault in a page together with the tag; doing that in one go is probably the only way that we can be sure that this is race-free on the QEMU side. Comments welcome :) Changes v1->v2: [Thanks to Eric for the feedback!] - add documentation - switch the mte prop to OnOffAuto; this improves the interaction with the existing mte machine prop - leave mte off for kvm by default - improve tests; the poking in QDicts feels a bit ugly, but seems to work Cornelia Huck (2): arm/kvm: add support for MTE qtests/arm: add some mte tests docs/system/arm/cpu-features.rst | 21 +++++ target/arm/cpu.c | 18 ++--- target/arm/cpu.h | 1 + target/arm/cpu64.c | 132 +++++++++++++++++++++++++++++++ target/arm/internals.h | 1 + target/arm/kvm64.c | 5 ++ target/arm/kvm_arm.h | 12 +++ target/arm/monitor.c | 1 + tests/qtest/arm-cpu-features.c | 77 ++++++++++++++++++ 9 files changed, 256 insertions(+), 12 deletions(-) -- 2.35.3
