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    KVM: PPC: book3s_pr: Simplify transitions between virtual and real mode · 02143947
    Paul Mackerras 提交于
    This simplifies the way that the book3s_pr makes the transition to
    real mode when entering the guest.  We now call kvmppc_entry_trampoline
    (renamed from kvmppc_rmcall) in the base kernel using a normal function
    call instead of doing an indirect call through a pointer in the vcpu.
    If kvm is a module, the module loader takes care of generating a
    trampoline as it does for other calls to functions outside the module.
    
    kvmppc_entry_trampoline then disables interrupts and jumps to
    kvmppc_handler_trampoline_enter in real mode using an rfi[d].
    That then uses the link register as the address to return to
    (potentially in module space) when the guest exits.
    
    This also simplifies the way that we call the Linux interrupt handler
    when we exit the guest due to an external, decrementer or performance
    monitor interrupt.  Instead of turning on the MMU, then deciding that
    we need to call the Linux handler and turning the MMU back off again,
    we now go straight to the handler at the point where we would turn the
    MMU on.  The handler will then return to the virtual-mode code
    (potentially in the module).
    
    Along the way, this moves the setting and clearing of the HID5 DCBZ32
    bit into real-mode interrupts-off code, and also makes sure that
    we clear the MSR[RI] bit before loading values into SRR0/1.
    
    The net result is that we no longer need any code addresses to be
    stored in vcpu->arch.
    Signed-off-by: NPaul Mackerras <paulus@samba.org>
    Signed-off-by: NAlexander Graf <agraf@suse.de>
    02143947
book3s_interrupts.S 4.9 KB