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authorWanpeng Li <wanpengli@tencent.com>2018-03-12 04:53:03 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2018-03-16 22:03:52 +0100
commitcaa057a2cad647fb368a12c8e6c410ac4c28e063 (patch)
tree704b511957703f1666b9735a516ec21c3e0865ae /Documentation/virtual
parent4d5422cea3b61f158d58924cbb43feada456ba5c (diff)
KVM: X86: Provide a capability to disable HLT intercepts
If host CPUs are dedicated to a VM, we can avoid VM exits on HLT. This patch adds the per-VM capability to disable them. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Jan H. Schönherr <jschoenh@amazon.de> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/api.txt2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 744a202cca31..e9c74876f177 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4367,6 +4367,7 @@ Returns: 0 on success, -EINVAL when args[0] contains invalid exits
Valid bits in args[0] are
#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0)
+#define KVM_X86_DISABLE_EXITS_HLT (1 << 1)
Enabling this capability on a VM provides userspace with a way to no
longer intercept some instructions for improved latency in some
@@ -4375,6 +4376,7 @@ physical CPUs. More bits can be added in the future; userspace can
just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable
all such vmexits.
+Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits.
8. Other capabilities.
----------------------