Re: [RFC PATCH 5/5] KVM: PPC: Book3S: Make kvmppc_handle_load/store handle any load or store

[Alexander Graf <agraf@suse.de>]

On 19.07.14 12:14, Paul Mackerras wrote:
> At present, kvmppc_handle_load and kvmppc_handle_store only handle
> emulated MMIO loads and stores.  This extends them to be able to handle
> loads and stores to guest memory as well.  This is so that
> kvmppc_emulate_instruction can be used to emulate loads and stores
> in cases other than when an attempt to execute the instruction by the
> CPU has resulted in an interrupt.
>
> To avoid having to look up the translation for the effective address
> again in kvmppc_handle_load/store when the caller of kvmppc_emulate_mmio
> has already done it, we arrange to pass down the translation in a new
> struct kvmppc_translated_address, which is a new argument to
> kvmppc_emulate_mmio() and kvmppc_emulate_instruction().  This also
> enables us to check that the guest hasn't replaced a load with a store
> instruction.
>
> This also makes the register updates for the paired-single FPU registers
> match for emulated MMIO accesses what is done for accesses to normal
> memory.
>
> The new code for accessing normal guest memory uses kvmppc_ld and kvmppc_st,
> which call kvmppc_xlate, which is only defined for Book 3S.  For Book E,
> kvmppc_handle_load/store still only work for emulated MMIO.
>
> Signed-off-by: Paul Mackerras <paulus@samba.org>

Please check out my other patch set where I made kvmppc_ld/st available 
for BookE and also split the MMIO path off completely. Since we do want 
to take the shortcut through paddr that we only know for memory traps, I 
really think we're better off treating that whole optimized code path as 
a separate piece.


Alex