[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 2/3] xen/hvm: introduce a fpu_uninitialised field to the CPU save record
On 17/11/15 18:44, Roger Pau Monne wrote: > Introduce a new filed to signal if the FPU has been initialised or not. Xen field > needs this new filed in order to know whether to set the FPU as initialised > or not during restore of CPU context. Previously Xen always wrongly assumed > the FPU was initialised on restore. > > Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx> > Cc: Jan Beulich <jbeulich@xxxxxxxx> > Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > --- > Changes since v1: > - Don't add yet another compat structure, new fields should always be added > to the end of the existing structure and offsetof should be used to > compare sizes. > - Leave the previous compat structure as-is, since the field was not added > to the end we cannot remove it and use offsetof in this case. How can this work? Making it zeroextended means that any short record will be padded with zeroes. As a result, the compat checking logic is skipped. (This HVM_SAVE_* infrastructure is truly horrifying code which should never have been accepted. I think I have correctly followed what it is doing, but I could be mistaken.) ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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