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    KVM: PPC: e500mc: Revert "add load inst fixup" · b5741bb3
    Mihai Caraman 提交于
    The commit 1d628af7 "add load inst fixup" made an attempt to handle
    failures generated by reading the guest current instruction. The fixup
    code that was added works by chance hiding the real issue.
    
    Load external pid (lwepx) instruction, used by KVM to read guest
    instructions, is executed in a subsituted guest translation context
    (EPLC[EGS] = 1). In consequence lwepx's TLB error and data storage
    interrupts need to be handled by KVM, even though these interrupts
    are generated from host context (MSR[GS] = 0) where lwepx is executed.
    
    Currently, KVM hooks only interrupts generated from guest context
    (MSR[GS] = 1), doing minimal checks on the fast path to avoid host
    performance degradation. As a result, the host kernel handles lwepx
    faults searching the faulting guest data address (loaded in DEAR) in
    its own Logical Partition ID (LPID) 0 context. In case a host translation
    is found the execution returns to the lwepx instruction instead of the
    fixup, the host ending up in an infinite loop.
    
    Revert the commit "add load inst fixup". lwepx issue will be addressed
    in a subsequent patch without needing fixup code.
    Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
    Signed-off-by: NAlexander Graf <agraf@suse.de>
    b5741bb3
bookehv_interrupts.S 20.8 KB