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| author | David Matlack <dmatlack@google.com> | 2020-04-17 15:14:46 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-04-24 12:53:17 -0400 |
| commit | acd05785e48c01edb2c4f4d014d28478b5f19fb5 (patch) | |
| tree | c8a7003b579cbdc7c79d109ec563f84de7d07018 /Documentation/virt | |
| parent | 87796555d48ca1cc681515e065b824ecab9c4282 (diff) | |
| download | linux-acd05785e48c01edb2c4f4d014d28478b5f19fb5.tar.bz2 | |
kvm: add capability for halt polling
KVM_CAP_HALT_POLL is a per-VM capability that lets userspace
control the halt-polling time, allowing halt-polling to be tuned or
disabled on particular VMs.
With dynamic halt-polling, a VM's VCPUs can poll from anywhere from
[0, halt_poll_ns] on each halt. KVM_CAP_HALT_POLL sets the
upper limit on the poll time.
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Jon Cargille <jcargill@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20200417221446.108733-1-jcargill@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index efbbe570aa9b..d871dacb984e 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -5802,6 +5802,23 @@ If present, this capability can be enabled for a VM, meaning that KVM will allow the transition to secure guest mode. Otherwise KVM will veto the transition. +7.20 KVM_CAP_HALT_POLL +---------------------- + +:Architectures: all +:Target: VM +: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. + 8. Other capabilities. ====================== |