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When a guest access a pseudo physical memory address,
the hypervisor tries to translate it to the equivalent machine address (real
memory). If the address does not exist in the guets's P2M (physical to
machine) translation then it is considered to be mmio, in this
case, a ioctl_t struct representing that access is being built and sent to the
device model of the HVM guest in domain0, there it is handled by the emulated
hardware.
Non-prefetchable MMIO (buffered) regions are being mapped
to the guest's memory layout and they actually a part of
it.
Since it is not prefetchable, a buffered mmio region
is also mapped to the device model and being accessed "randomly", preformance is
better this way.
Thanks,
Guy.
What is the MMIO address space of Xen HVM?
What happen when I read from or write to
these IO ports?
Thanks,
Huahang
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