Second batch of KVM updates for v4.13

Common:
 - add uevents for VM creation/destruction
 - annotate and properly access RCU-protected objects

s390:
 - rename IOCTL added in the first v4.13 merge

x86:
 - emulate VMLOAD VMSAVE feature in SVM
 - support paravirtual asynchronous page fault while nested
 - add Hyper-V userspace interfaces for better migration
 - improve master clock corner cases
 - extend internal error reporting after EPT misconfig
 - correct single-stepping of emulated instructions in SVM
 - handle MCE during VM entry
 - fix nVMX VM entry checks and nVMX VMCS shadowing
kvm: x86: hyperv: make VP_INDEX managed by userspace

Hyper-V identifies vCPUs by Virtual Processor Index, which can be
queried via HV_X64_MSR_VP_INDEX msr.  It is defined by the spec as a
sequential number which can't exceed the maximum number of vCPUs per VM.
APIC ids can be sparse and thus aren't a valid replacement for VP
indices.

Current KVM uses its internal vcpu index as VP_INDEX.  However, to make
it predictable and persistent across VM migrations, the userspace has to
control the value of VP_INDEX.

This patch achieves that, by storing vp_index explicitly on vcpu, and
allowing HV_X64_MSR_VP_INDEX to be set from the host side.  For
compatibility it's initialized to KVM vcpu index.  Also a few variables
are renamed to make clear distinction betweed this Hyper-V vp_index and
KVM vcpu_id (== APIC id).  Besides, a new capability,
KVM_CAP_HYPERV_VP_INDEX, is added to allow the userspace to skip
attempting msr writes where unsupported, to avoid spamming error logs.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
6 files changed