Messages in this thread | | | Subject | Re: [PATCH v3 3/5] arch/x86/mm: Refactor cond_ibpb() to support other use cases | From | "Singh, Balbir" <> | Date | Fri, 17 Apr 2020 23:02:22 +0000 |
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On Fri, 2020-04-17 at 15:07 +0200, Thomas Gleixner wrote: > > Balbir Singh <sblbir@amazon.com> writes: > > > > /* > > - * Use bit 0 to mangle the TIF_SPEC_IB state into the mm pointer which is > > - * stored in cpu_tlb_state.last_user_mm_ibpb. > > + * Bits to mangle the TIF_SPEC_IB state into the mm pointer which is > > + * stored in cpu_tlb_state.last_user_mm_spec. > > */ > > #define LAST_USER_MM_IBPB 0x1UL > > +#define LAST_USER_MM_SPEC_MASK (LAST_USER_MM_IBPB) > > > > /* Reinitialize tlbstate. */ > > - this_cpu_write(cpu_tlbstate.last_user_mm_ibpb, LAST_USER_MM_IBPB); > > + this_cpu_write(cpu_tlbstate.last_user_mm_spec, LAST_USER_MM_IBPB); > > Shouldn't that be LAST_USER_MM_MASK? > >
No, that crashes the system for SW flushes, because it tries to flush the L1D via the software loop and early enough we don't have the l1d_flush_pages allocated. LAST_USER_MM_MASK has LAST_USER_MM_FLUSH_L1D bit set.
Balbir Singh.
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