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| author |   Wanpeng Li <wanpengli@tencent.com> | 2018-02-13 09:05:40 +0800 |
|---|---|---|
| committer |   Radim Krčmář <rkrcmar@redhat.com> | 2018-03-06 18:40:44 +0100 |
| commit | a4429e53c9b3082b05e51224c3d58dbdd39306c5 (patch) | |
| tree | d0fbeff12679477198902c365cb23ad6b645747c /Documentation/virtual | |
| parent | kvm: use insert sort in kvm_io_bus_register_dev function (diff) | |
| download | linux-dev-a4429e53c9b3082b05e51224c3d58dbdd39306c5.tar.xz linux-dev-a4429e53c9b3082b05e51224c3d58dbdd39306c5.zip | |
KVM: Introduce paravirtualization hints and KVM_HINTS_DEDICATED
This patch introduces kvm_para_has_hint() to query for hints about
the configuration of the guests. The first hint KVM_HINTS_DEDICATED,
is set if the guest has dedicated physical CPUs for each vCPU (i.e.
pinning and no over-commitment). This allows optimizing spinlocks
and tells the guest to avoid PV TLB flush.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'Documentation/virtual')
| -rw-r--r-- | Documentation/virtual/kvm/cpuid.txt | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt index 87a7506f31c2..d4f33eb805dd 100644 --- a/Documentation/virtual/kvm/cpuid.txt +++ b/Documentation/virtual/kvm/cpuid.txt @@ -23,8 +23,8 @@ This function queries the presence of KVM cpuid leafs. function: define KVM_CPUID_FEATURES (0x40000001) -returns : ebx, ecx, edx = 0 - eax = and OR'ed group of (1 << flag), where each flags is: +returns : ebx, ecx + eax = an OR'ed group of (1 << flag), where each flags is: flag || value || meaning @@ -66,3 +66,14 @@ KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side || || per-cpu warps are expected in || || kvmclock. ------------------------------------------------------------------------------ + + edx = an OR'ed group of (1 << flag), where each flags is: + + +flag || value || meaning +================================================================================== +KVM_HINTS_DEDICATED || 0 || guest checks this feature bit to + || || determine if there is vCPU pinning + || || and there is no vCPU over-commitment, + || || allowing optimizations +---------------------------------------------------------------------------------- |