ACK: [SRU Bionic 0/1] LP: #1872401 - nested KVM pauses L1

[Colin Ian King]

On 03/12/2020 20:33, Thadeu Lima de Souza Cascardo wrote:
> [Impact]
> When running kvm-unit-tests under a guest, it will be paused, requiring a
> reset. When running the same test on a host (vmx_nm_test), it will fail.
> 
> [Test case]
> Grab kvm-unit-tests, build it and run:
> 
> TESTNAME=vmx TIMEOUT=90s ACCEL= ./x86/run x86/vmx.flat -smp 1 -cpu host,+vmx -append "vmx_nm_test"
> 
> If done inside a guest, when the host runs the bionic 4.15 kernel, the guest
> will pause.
> 
> [Potential regressions]
> Nested KVM could stop working. Floating point could stop working on KVM
> guests, though the code that relied on this was already removed from
> Bionic.
> 
> Jim Mattson (1):
>   KVM: nVMX: Always reflect #NM VM-exits to L1
> 
>  arch/x86/kvm/vmx.c | 8 --------
>  1 file changed, 8 deletions(-)
> 

Test case looks sane to me. The regression potential sounds a bit
concerning but we do seem to have adequate testing to check for this.
Clean upstream cherry pick, so..

Acked-by: Colin Ian King <colin.king at canonical.com>