Minor code cleanups for PPC.

For x86 this brings in PCID emulation and CR3 caching for shadow page
 tables, nested VMX live migration, nested VMCS shadowing, an optimized
 IPI hypercall, and some optimizations.
 
 ARM will come next week.
 
 There is a semantic conflict because tip also added an .init_platform
 callback to kvm.c.  Please keep the initializer from this branch,
 and add a call to kvmclock_init (added by tip) inside kvm_init_platform
 (added here).
 
 Also, there is a backmerge from 4.18-rc6.  This is because of a
 refactoring that conflicted with a relatively late bugfix and
 resulted in a particularly hellish conflict.  Because the conflict
 was only due to unfortunate timing of the bugfix, I backmerged and
 rebased the refactoring rather than force the resolution on you.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull first set of KVM updates from Paolo Bonzini:
 "PPC:
   - minor code cleanups

  x86:
   - PCID emulation and CR3 caching for shadow page tables
   - nested VMX live migration
   - nested VMCS shadowing
   - optimized IPI hypercall
   - some optimizations

  ARM will come next week"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (85 commits)
  kvm: x86: Set highest physical address bits in non-present/reserved SPTEs
  KVM/x86: Use CC_SET()/CC_OUT in arch/x86/kvm/vmx.c
  KVM: X86: Implement PV IPIs in linux guest
  KVM: X86: Add kvm hypervisor init time platform setup callback
  KVM: X86: Implement "send IPI" hypercall
  KVM/x86: Move X86_CR4_OSXSAVE check into kvm_valid_sregs()
  KVM: x86: Skip pae_root shadow allocation if tdp enabled
  KVM/MMU: Combine flushing remote tlb in mmu_set_spte()
  KVM: vmx: skip VMWRITE of HOST_{FS,GS}_BASE when possible
  KVM: vmx: skip VMWRITE of HOST_{FS,GS}_SEL when possible
  KVM: vmx: always initialize HOST_{FS,GS}_BASE to zero during setup
  KVM: vmx: move struct host_state usage to struct loaded_vmcs
  KVM: vmx: compute need to reload FS/GS/LDT on demand
  KVM: nVMX: remove a misleading comment regarding vmcs02 fields
  KVM: vmx: rename __vmx_load_host_state() and vmx_save_host_state()
  KVM: vmx: add dedicated utility to access guest's kernel_gs_base
  KVM: vmx: track host_state.loaded using a loaded_vmcs pointer
  KVM: vmx: refactor segmentation code in vmx_save_host_state()
  kvm: nVMX: Fix fault priority for VMX operations
  kvm: nVMX: Fix fault vector for VMX operation at CPL > 0
  ...

include/uapi/linux/kvm.h

@@ -950,6 +950,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_HYPERV_EVENTFD 154
 #define KVM_CAP_HYPERV_TLBFLUSH 155
 #define KVM_CAP_S390_HPAGE_1M 156
+#define KVM_CAP_NESTED_STATE 157
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1392,6 +1393,9 @@ struct kvm_enc_region {
 /* Available with KVM_CAP_HYPERV_EVENTFD */
 #define KVM_HYPERV_EVENTFD        _IOW(KVMIO,  0xbd, struct kvm_hyperv_eventfd)
 
+/* Available with KVM_CAP_NESTED_STATE */
+#define KVM_GET_NESTED_STATE         _IOWR(KVMIO, 0xbe, struct kvm_nested_state)
+#define KVM_SET_NESTED_STATE         _IOW(KVMIO,  0xbf, struct kvm_nested_state)
 
 /* Secure Encrypted Virtualization command */
 enum sev_cmd_id {

include/uapi/linux/kvm_para.h

@@ -13,6 +13,7 @@
 /* Return values for hypercalls */
 #define KVM_ENOSYS		1000
 #define KVM_EFAULT		EFAULT
+#define KVM_EINVAL		EINVAL
 #define KVM_E2BIG		E2BIG
 #define KVM_EPERM		EPERM
 #define KVM_EOPNOTSUPP		95
@@ -26,6 +27,7 @@
 #define KVM_HC_MIPS_EXIT_VM		7
 #define KVM_HC_MIPS_CONSOLE_OUTPUT	8
 #define KVM_HC_CLOCK_PAIRING		9
+#define KVM_HC_SEND_IPI		10
 
 /*
  * hypercalls use architecture specific