Messages in this thread | | | Date | Mon, 19 Jun 2023 07:31:21 -0700 | Subject | Re: [PATCH v11 18/20] x86: Handle TDX erratum to reset TDX private memory during kexec() and reboot | From | Dave Hansen <> |
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On 6/19/23 04:43, Huang, Kai wrote: > On Mon, 2023-06-12 at 06:47 -0700, Dave Hansen wrote: >> On 6/12/23 03:27, Huang, Kai wrote: >>> So I think a __mb() after setting tdmr->pamt_4k_base should be good enough, as >>> it guarantees when setting to any pamt_*_size happens, the valid pamt_4k_base >>> will be seen by other cpus. >>> >>> Does it make sense? >> Just use a normal old atomic_t or set_bit()/test_bit(). They have >> built-in memory barriers are are less likely to get botched. > Hi Dave, > > Using atomic_set() requires changing tdmr->pamt_4k_base to atomic_t, which is a > little bit silly or overkill IMHO. Looking at the code, it seems > arch_atomic_set() simply uses __WRITE_ONCE():
How about _adding_ a variable that protects tdmr->pamt_4k_base? Wouldn't that be more straightforward than mucking around with existing types?
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