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[PATCH 0/5] tcg: Issue memory barriers for guest memory model
From: |
Richard Henderson |
Subject: |
[PATCH 0/5] tcg: Issue memory barriers for guest memory model |
Date: |
Tue, 16 Mar 2021 16:07:30 -0600 |
This is intending to fix the current aarch64 host failure
for s390x guest cdrom-test. This is caused by the io thread
issuing memory barriers that are supposed to be matched by
the vcpu, but are elided by tcg in rr mode as "unnecessary".
I know Peter would like a smaller patch to sync the io thread
with the vcpu thread. I've made a couple of attempts at this,
but havn't managed to get something reliable (although now
irritatingly infrequent -- about 1 in 500).
I have further patches to further optimize barriers, and to
generate load-acquire/store-release instructions in tcg.
But it's late in the release cycle, etc etc.
I've done nothing to measure the performance impact of this.
I quit the cdtom-test cycle after 4000 passes.
r~
Richard Henderson (5):
tcg: Decode the operand to INDEX_op_mb in dumps
tcg: Do not elide memory barriers for CF_PARALLEL
tcg: Elide memory barriers implied by the host memory model
tcg: Create tcg_req_mo
tcg: Add host memory barriers to cpu_ldst.h interfaces
include/exec/cpu_ldst.h | 7 ++++
include/tcg/tcg.h | 20 +++++++++++
accel/tcg/cputlb.c | 2 ++
accel/tcg/tcg-all.c | 6 +---
accel/tcg/user-exec.c | 17 +++++++++
tcg/tcg-op.c | 19 +++++-----
tcg/tcg.c | 79 +++++++++++++++++++++++++++++++++++++++++
7 files changed, 137 insertions(+), 13 deletions(-)
--
2.25.1
- [PATCH 0/5] tcg: Issue memory barriers for guest memory model,
Richard Henderson <=
- [PATCH 1/5] tcg: Decode the operand to INDEX_op_mb in dumps, Richard Henderson, 2021/03/16
- [PATCH 2/5] tcg: Do not elide memory barriers for CF_PARALLEL, Richard Henderson, 2021/03/16
- [PATCH 3/5] tcg: Elide memory barriers implied by the host memory model, Richard Henderson, 2021/03/16
- [PATCH 5/5] tcg: Add host memory barriers to cpu_ldst.h interfaces, Richard Henderson, 2021/03/16
- [PATCH 4/5] tcg: Create tcg_req_mo, Richard Henderson, 2021/03/16
- Re: [PATCH 0/5] tcg: Issue memory barriers for guest memory model, no-reply, 2021/03/16