Hi Peter, On 2/9/24 19:57, Peter Maydell wrote: > On Fri, 9 Feb 2024 at 16:00, Eric Auger <eric.au...@redhat.com> wrote: >> This series adds ARM Nested Virtualization support in KVM mode. >> This is a respin of previous contributions from Miguel [1] and Haibo [2]. >> >> This was tested with Marc's v11 [3] on Ampere HW with fedora L1 guest and >> L2 guests booted without EDK2. However it does not work yet with >> EDK2 but it looks unrelated to this qemu integration (host hard lockups). >> >> The host needs to be booted with "kvm-arm.mode=nested" option and >> qemu needs to be invoked with : >> >> -machine virt,virtualization=on >> >> There is a known issue with hosts supporting SVE. Kernel does not support >> both >> SVE and NV2 and the current qemu integration has an issue with the >> scratch_host_vcpu startup because both are enabled if exposed by the kernel. >> This is independent on whether sve is disabled on the command line. >> Unfortunately >> I lost access to the HW that expose that issue so I couldn't fix it in this >> version. > You can probably repro that by running the whole setup under > QEMU's FEAT_NV emulation, which will be able to give you a CPU > with both FEAT_NV and SVE.
indeed, this should work now we have FEAT_NV. > > Personally I think that this is a kernel missing-feature that > should really be fixed as part of getting the kernel patches > upstreamed. There's no cause to force every userspace VMM to > develop extra complications for this. yes maybe this will be fixed later on. Thanks! Eric > > thanks > -- PMM >
