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| author |   Zeng Guang <guang.zeng@intel.com> | 2022-04-19 23:44:44 +0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2022-06-08 04:47:31 -0400 |
| commit | 35875316384b71d23dc2a45a969732fc8cab16af (patch) | |
| tree | 68c6884064bf6e7827c802d9b72aff9b966df290 /arch/x86/include/asm/kvm_host.h | |
| parent | KVM: Move kvm_arch_vcpu_precreate() under kvm->lock (diff) | |
| download | linux-dev-35875316384b71d23dc2a45a969732fc8cab16af.tar.xz linux-dev-35875316384b71d23dc2a45a969732fc8cab16af.zip | |
KVM: x86: Allow userspace to set maximum VCPU id for VM
Introduce new max_vcpu_ids in KVM for x86 architecture. Userspace
can assign maximum possible vcpu id for current VM session using
KVM_CAP_MAX_VCPU_ID of KVM_ENABLE_CAP ioctl().
This is done for x86 only because the sole use case is to guide
memory allocation for PID-pointer table, a structure needed to
enable VMX IPI.
By default, max_vcpu_ids set as KVM_MAX_VCPU_IDS.
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Zeng Guang <guang.zeng@intel.com>
Message-Id: <20220419154444.11888-1-guang.zeng@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/kvm_host.h')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 8109805b5429..9dc8d6d0a67d 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1243,6 +1243,12 @@ struct kvm_arch { hpa_t hv_root_tdp; spinlock_t hv_root_tdp_lock; #endif + /* + * VM-scope maximum vCPU ID. Used to determine the size of structures + * that increase along with the maximum vCPU ID, in which case, using + * the global KVM_MAX_VCPU_IDS may lead to significant memory waste. + */ + u32 max_vcpu_ids; }; struct kvm_vm_stat { |