[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86/HVM: refuse doing string operations in certain situations
>>> On 20.09.13 at 22:05, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote: > On Fri, Sep 20, 2013 at 02:08:45PM +0100, Jan Beulich wrote: >> We shouldn't do any acceleration for >> - "rep movs" when either side is passed through MMIO or when both sides >> are handled by qemu >> - "rep ins" and "rep outs" when the memory operand is any kind of MMIO > > Could you explain this in a bit more details? > > Why is acceleration in those cases bad? - we currently can't have more than one request issued to qemu for a single guest side instruction (there's only one ioreq_t instance per vCPU) - hvm_copy_{to,from}_guest_phys() don't honor the original access size Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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