• James Hogan's avatar
    MIPS: KVM/locore.S: Don't preserve host ASID around vcpu_run · 5fb59fd2
    James Hogan authored
    MIPS KVM uses different ASIDs for guest execution than for the host.
    The host ASID is saved on the stack when entering the guest with
    __kvm_mips_vcpu_run(), and restored again before returning back to the
    caller (exit to userland).
    
    - This does not take into account that pre-emption may have taken place
      during that time, which may have started a new ASID cycle and resulted
      in that process' ASID being invalidated and reused.
    
    - This does not take into account that the process may have migrated to
      a different CPU during that time, with a different ASID assignment
      since they are managed per-CPU.
    
    - It is actually redundant, since the host ASID will be restored
      correctly by kvm_arch_vcpu_put(), which is called almost immediately
      after kvm_arch_vcpu_ioctl_run() returns.
    
    Therefore drop this code from locore.S
    Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
    Cc: Paolo Bonzini <pbonzini@redhat.com>
    Cc: Radim Krčmář <rkrcmar@redhat.com>
    Cc: Paul Burton <paul.burton@imgtec.com>
    Cc: linux-mips@linux-mips.org
    Cc: kvm@vger.kernel.org
    Patchwork: https://patchwork.linux-mips.org/patch/13206/Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
    5fb59fd2
locore.S 14.6 KB