[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 16/17] x86/hvm: always re-emulate I/O from a buffer
>>> On 24.06.15 at 13:24, <paul.durrant@xxxxxxxxxx> wrote: > If memory mapped I/O is 'chunked' then the I/O must be re-emulated, > otherwise only the first chunk will be processed. This patch makes > sure all I/O from a buffer is re-emulated regardless of whether it > is a read or a write. I'm not sure I understand this: Isn't the reason for treating reads and writes differently due to the fact that MMIO reads may have side effects, and hence can't be re-issued (whereas writes are always the last thing an instruction does, and hence can't hold up retiring of it, and hence don't need retrying)? Furthermore, doesn't "only the first chunk" get represented correctly already by informing the caller that only a single iteration of a repeated instruction was done, such that further repeats will get carried out anyway (resulting in another, fresh cycle through the emulator)? Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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