Re: [Xen-devel] stale TLB contents?

To:	Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>
Subject:	Re: [Xen-devel] stale TLB contents?
From:	George Dunlap <dunlapg@xxxxxxxxx>
Date:	Mon, 24 Jan 2011 13:11:11 +0000
Cc:	"xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
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If you're talking about just TLB  stuff (not changes to the EPT
tables), that should happen as a result of the context switch code
(nothing to do with EPT).  The code in question is here:

xen/arch/x86/domain.c:context_switch()
    if ( unlikely(!cpu_isset(cpu, dirty_mask) && !cpus_empty(dirty_mask)) )
    {
        /* Other cpus call __sync_local_execstate from flush ipi handler. */
        flush_tlb_mask(&dirty_mask);
    }

"Dirty  mask" means "where this vcpu has run"; since the vcpu in
question will have run on another pcpu, this should happen before the
vcpu is allowed to run on cpu 0 again.

 -George

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Re: [Xen-devel] stale TLB contents?