On Mon, 7 Feb 2022 15:52:37 +0100 Janosch Frank <frankja@xxxxxxxxxxxxx> wrote: > On 2/4/22 16:53, Claudio Imbrenda wrote: > > Add documentation for the new commands added to the KVM_S390_PV_COMMAND > > ioctl. > > > > Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> > > --- > > Documentation/virt/kvm/api.rst | 21 ++++++++++++++++++--- > > 1 file changed, 18 insertions(+), 3 deletions(-) > > > > diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst > > index a4267104db50..3b9068aceead 100644 > > --- a/Documentation/virt/kvm/api.rst > > +++ b/Documentation/virt/kvm/api.rst > > @@ -5010,11 +5010,13 @@ KVM_PV_ENABLE > > ===== ============================= > > > > KVM_PV_DISABLE > > - > > Deregister the VM from the Ultravisor and reclaim the memory that > > had been donated to the Ultravisor, making it usable by the kernel > > - again. All registered VCPUs are converted back to non-protected > > - ones. > > + again. All registered VCPUs are converted back to non-protected > > + ones. If a previous VM had been prepared for asynchonous teardown > > + with KVM_PV_ASYNC_DISABLE_PREPARE and not actually torn down with > > + KVM_PV_ASYNC_DISABLE, it will be torn down in this call together with > > + the current VM. > > > > KVM_PV_VM_SET_SEC_PARMS > > Pass the image header from VM memory to the Ultravisor in > > @@ -5027,6 +5029,19 @@ KVM_PV_VM_VERIFY > > Verify the integrity of the unpacked image. Only if this succeeds, > > KVM is allowed to start protected VCPUs. > > > > +KVM_PV_ASYNC_DISABLE_PREPARE > > + Prepare the current protected VM for asynchronous teardown. The current > > I think the first sentence needs a few more examples of what we do so > the second sentence makes more sense. > > ...by setting aside the pointers to the donated storage, replacing the > top most page table, destroying the first 2GB of memory and zeroing the > KVM PV structs. I'm not sure we should give out implementation details, which might change with newer kernel and/or hardware versions > > > Or something which sounds a bit nicer. > > > + VM will then continue immediately as non-protected. If a protected VM had > > + already been set aside without starting the teardown process, this call > > + will fail. In this case the userspace process should issue a normal > > + KVM_PV_DISABLE. > > + > > +KVM_PV_ASYNC_DISABLE > > + Tear down the protected VM previously set aside for asynchronous teardown. > > + This PV command should ideally be issued by userspace from a separate > > + thread. If a fatal signal is received (or the process terminates > > + naturally), the command will terminate immediately without completing. > > + > > 4.126 KVM_X86_SET_MSR_FILTER > > ---------------------------- > > > > >
