On 09/20/2012 02:16 PM, Alex Williamson wrote:
On Thu, 2012-09-20 at 13:27 -0400, Etienne Martineau wrote:
In hw/kvm/pci-assign.c a pread() error part of assigned_dev_pci_read()
result in a hw_error(). Similarly a pwrite() error part of
assigned_dev_pci_write() also result in a hw_error().
Would there be a way to avoid terminating the guest for those cases? How
about we deassign the device upon error?
By terminating the guest we contain the error vs allowing the guest to
continue running with invalid data. De-assigning the device is
asynchronous and relies on guest involvement, so damage is potentially
already done. Is this a theoretical problem or do you actually have
hardware that hits this? Thanks,
Alex
This problem is in the context of a Hot-pluggable device assigned to the
guest. If the guest rd/wr the config space at the same time than the
device is physically taken out then the guest will terminate with
hw_error().
Because this limits the availability of the guest I think we should try
to recover instead. I don't see what other damage can happen since
guest's MMIO access to the stale device will go nowhere?
-Etienne
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