Commit 5b3e0cd8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 

Pull kvm fixes from Paolo Bonzini:
 "Unless anything comes from the ARM side, this should be the last pull
  request for this release - and it's mostly documentation:

   - Document the interaction between KVM_CAP_HALT_POLL and halt_poll_ns

   - s390: fix multi-epoch extension in nested guests

   - x86: fix uninitialized variable on nested triple fault"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: Document the interaction between KVM_CAP_HALT_POLL and halt_poll_ns
  KVM: Move halt-polling documentation into common directory
  KVM: x86: fix uninitialized variable use on KVM_REQ_TRIPLE_FAULT
  KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field
parents b71101d6 34e30ebb

Documentation/virt/kvm/api.rst

+7 −8
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@@ -7213,14 +7213,13 @@ veto the transition. 
:Parameters: args[0] is the maximum poll time in nanoseconds

:Returns: 0 on success; -1 on error



This capability overrides the kvm module parameter halt_poll_ns for the

target VM.



VCPU polling allows a VCPU to poll for wakeup events instead of immediately

scheduling during guest halts. The maximum time a VCPU can spend polling is

controlled by the kvm module parameter halt_poll_ns. This capability allows

the maximum halt time to specified on a per-VM basis, effectively overriding

the module parameter for the target VM.

KVM_CAP_HALT_POLL overrides the kvm.halt_poll_ns module parameter to set the

maximum halt-polling time for all vCPUs in the target VM. This capability can

be invoked at any time and any number of times to dynamically change the

maximum halt-polling time.



See Documentation/virt/kvm/halt-polling.rst for more information on halt

polling.



7.21 KVM_CAP_X86_USER_SPACE_MSR

-------------------------------

Documentation/virt/kvm/x86/halt-polling.rst→Documentation/virt/kvm/halt-polling.rst

+13 −0
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@@ -119,6 +119,19 @@ These module parameters can be set from the debugfs files in: 
Note: that these module parameters are system wide values and are not able to

      be tuned on a per vm basis.



Any changes to these parameters will be picked up by new and existing vCPUs the

next time they halt, with the notable exception of VMs using KVM_CAP_HALT_POLL

(see next section).



KVM_CAP_HALT_POLL

=================



KVM_CAP_HALT_POLL is a VM capability that allows userspace to override halt_poll_ns

on a per-VM basis. VMs using KVM_CAP_HALT_POLL ignore halt_poll_ns completely (but

still obey halt_poll_ns_grow, halt_poll_ns_grow_start, and halt_poll_ns_shrink).



See Documentation/virt/kvm/api.rst for more information on this capability.



Further Notes

=============

Documentation/virt/kvm/index.rst

+1 −0
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@@ -17,4 +17,5 @@ KVM 


   locking

   vcpu-requests

   halt-polling

   review-checklist

Documentation/virt/kvm/x86/index.rst

+0 −1
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@@ -10,7 +10,6 @@ KVM for x86 systems 
   amd-memory-encryption

   cpuid

   errata

   halt-polling

   hypercalls

   mmu

   msr

arch/s390/kvm/vsie.c

+3 −1
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@@ -546,8 +546,10 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) 
	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))

		scb_s->eca |= scb_o->eca & ECA_CEI;

	/* Epoch Extension */

	if (test_kvm_facility(vcpu->kvm, 139))

	if (test_kvm_facility(vcpu->kvm, 139)) {

		scb_s->ecd |= scb_o->ecd & ECD_MEF;

		scb_s->epdx = scb_o->epdx;

	}



	/* etoken */

	if (test_kvm_facility(vcpu->kvm, 156))