Messages in this thread | | | Date | Wed, 07 May 2014 17:52:35 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCH 4/5] KVM: x86: Wrong register masking in 64-bit mode |
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Il 07/05/2014 14:32, Nadav Amit ha scritto: > 32-bit operations are zero extended in 64-bit mode. Currently, the code does > not handle them correctly and keeps the high bits. In 16-bit mode, the high > 32-bits are kept intact. > > In addition, although it is not well-documented, when address override prefix > is used with REP-string instruction, RCX high half is zeroed even if ECX was > zero on the first iteration (as if an assignment was performed to ECX).
Is this true even for REPZ and ZF=0 or REPNZ and ZF=1?
Paolo
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