On 11/4/19 3:18 PM, Cornelia Huck wrote: > 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,/ Fixed > >> +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." ? I applied your proposal, but removed the part in the brace, as it is obvious from the words that follow. > >> + >> +Each guest starts in the non-protected mode and then transitions into > > "and then may make a request to transition into protected mode" ? Sure > >> +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. >
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