• Longpeng(Mike)'s avatar
    KVM: add spinlock optimization framework · 199b5763
    Longpeng(Mike) authored
    If a vcpu exits due to request a user mode spinlock, then
    the spinlock-holder may be preempted in user mode or kernel mode.
    (Note that not all architectures trap spin loops in user mode,
    only AMD x86 and ARM/ARM64 currently do).
    
    But if a vcpu exits in kernel mode, then the holder must be
    preempted in kernel mode, so we should choose a vcpu in kernel mode
    as a more likely candidate for the lock holder.
    
    This introduces kvm_arch_vcpu_in_kernel() to decide whether the
    vcpu is in kernel-mode when it's preempted.  kvm_vcpu_on_spin's
    new argument says the same of the spinning VCPU.
    Signed-off-by: default avatarLongpeng(Mike) <longpeng2@huawei.com>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    199b5763
handle_exit.c 4.69 KB