On Thu, 24 Oct 2019 07:40:23 -0400 Janosch Frank <frankja@xxxxxxxxxxxxx> wrote: > Introduction to Protected VMs. > > Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx> > --- > Documentation/virtual/kvm/s390-pv.txt | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > create mode 100644 Documentation/virtual/kvm/s390-pv.txt > > diff --git a/Documentation/virtual/kvm/s390-pv.txt b/Documentation/virtual/kvm/s390-pv.txt > new file mode 100644 > index 000000000000..86ed95f36759 > --- /dev/null > +++ b/Documentation/virtual/kvm/s390-pv.txt This should be under /virt/, I think. Also, maybe start out with RST already for new files? > @@ -0,0 +1,23 @@ > +Ultravisor and Protected VMs > +=========================== > + > +Summary: > + > +Protected VMs (PVM) are KVM VMs, where KVM can't access the VM's state > +like guest memory and guest registers anymore. Instead the PVMs are s/Instead/Instead,/ > +mostly managed by a new entity called Ultravisor (UV), which provides > +an API, so KVM and the PVM can request management actions. Hm... "The UV provides an API (both for guests and hypervisors), where PVMs and KVM can request management actions." ? > + > +Each guest starts in the non-protected mode and then transitions into "and then may make a request to transition into protected mode" ? > +protected mode. On transition KVM registers the guest and its VCPUs > +with the Ultravisor and prepares everything for running it. > + > +The Ultravisor will secure and decrypt the guest's boot memory > +(i.e. kernel/initrd). It will safeguard state changes like VCPU > +starts/stops and injected interrupts while the guest is running. > + > +As access to the guest's state, like the SIE state description is "such as the SIE state description," ? > +normally needed to be able to run a VM, some changes have been made in > +SIE behavior and fields have different meaning for a PVM. SIE exits > +are minimized as much as possible to improve speed and reduce exposed > +guest state.
