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Date: Wed, 25 Oct 2017 21:47:50 -0400
From: "Emilio G. Cota" <cota@braap.org>
Message-ID: <20171026014750.GA5446@flamenco>
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Subject: Re: [Qemu-devel] [PATCH v6 00/50] tcg tb_lock removal
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org

I have given a respin to the tb_lock branch on top of master.
Turns out the freezes I was getting were due to the magic we used
to rely on (e.g. for icount). Works now!

The branch is here:
  https://github.com/cota/qemu/tree/tb-lock

Boot-tested on ppc64, aarch64 and alpha smp guests (<=64) with MTTCG.

A couple of questions:

- Does anyone remember what work remains to be done to safely enable
  MTTCG for i386? I just forced it on: without the tb lock removal
  I booted an 8-core guest, but without tb_lock the guest kernel
  dies pretty quickly. So I guess there's still work to do.

- In user-mode without tb_lock, should I worry about fork happening
  while any of the newly-introduced locks are held? For instance,
  tb->jmp_lock (introduced in "translate-all: protect TB jumps with
  a per-destination-TB lock"), or tcg_region_tree's lock.

Thanks,

		Emilio