From: Borislav Petkov <bp@alien8.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Luck, Tony" <tony.luck@intel.com>,
Linux NVDIMM <nvdimm@lists.linux.dev>,
Jane Chu <jane.chu@oracle.com>,
Luis Chamberlain <mcgrof@suse.com>
Subject: Re: [RFT PATCH] x86/pat: Fix set_mce_nospec() for pmem
Date: Thu, 30 Sep 2021 22:54:08 +0200 [thread overview]
Message-ID: <YVYj8PpzIIo1qu1U@zn.tnic> (raw)
In-Reply-To: <CAPcyv4iHmcYV6Dc35Rfp_k9oMsr9qWEdALFs70-bNOvZK00f9A@mail.gmail.com>
On Thu, Sep 30, 2021 at 01:39:03PM -0700, Dan Williams wrote:
> Yes, that's a good way to think about it. The only way to avoid poison
> for page allocator pages is to just ditch the page. In the case of
> PMEM the driver can do this fine grained dance because it gets precise
> sub-page poison lists to consult and implements a non-mmap path to
> access the page contents.
Ok, good.
Now, before we do anything further here, I'd like for this very much
non-obvious situation to be documented in detail so that we know what's
going on there and what that whole_page notion even means. Because this
is at least bending the meaning of page states like poison and what that
really means for the underlying thing - PMEM or general purpose DIMMs.
And then that test could be something like:
/*
* Normal DRAM gets poisoned as a whole page, yadda yadda...
/
if (whole_page) {
/*
* Special handling for PMEM case, driver can handle accessing sub-page ranges
* even if the whole "page" is poisoned, blabla
} else {
rc = _set_memory_uc(decoy_addr, 1);
...
so that it is crystal clear what's going on there.
Thx!
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-09-30 20:54 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-07 1:01 [RFT PATCH] x86/pat: Fix set_mce_nospec() for pmem Dan Williams
2021-08-26 19:08 ` Dan Williams
2021-08-27 7:12 ` Jane Chu
2021-09-13 10:29 ` Borislav Petkov
2021-09-14 18:08 ` Dan Williams
2021-09-15 10:41 ` Borislav Petkov
2021-09-16 20:33 ` Dan Williams
2021-09-17 11:30 ` Borislav Petkov
2021-09-21 2:04 ` Dan Williams
2021-09-30 17:19 ` Borislav Petkov
2021-09-30 17:28 ` Luck, Tony
2021-09-30 19:30 ` Borislav Petkov
2021-09-30 19:41 ` Dan Williams
2021-09-30 19:44 ` Luck, Tony
2021-09-30 20:01 ` Borislav Petkov
2021-09-30 20:15 ` Luck, Tony
2021-09-30 20:32 ` Borislav Petkov
2021-09-30 20:39 ` Dan Williams
2021-09-30 20:54 ` Borislav Petkov [this message]
2021-09-30 21:05 ` Dan Williams
2021-09-30 21:20 ` Borislav Petkov
2021-09-30 21:41 ` Dan Williams
2021-09-30 22:35 ` Borislav Petkov
2021-09-30 22:44 ` Dan Williams
2021-10-01 10:41 ` Borislav Petkov
2021-10-01 0:43 ` Jane Chu
2021-10-01 2:02 ` Dan Williams
2021-10-01 10:50 ` Borislav Petkov
2021-10-01 16:52 ` Dan Williams
2021-10-01 18:11 ` Borislav Petkov
2021-10-01 18:29 ` Dan Williams
2021-10-02 10:17 ` Borislav Petkov
2021-11-11 0:06 ` Jane Chu
2021-11-12 0:30 ` Jane Chu
2021-11-12 0:51 ` Dan Williams
2021-11-12 17:57 ` Jane Chu
2021-11-12 19:24 ` Dan Williams
2021-11-12 22:35 ` Jane Chu
2021-11-12 22:50 ` Jane Chu
2021-11-12 23:08 ` Dan Williams
2021-11-13 5:50 ` Jane Chu
2021-11-13 20:47 ` Dan Williams
2021-11-18 19:03 ` Jane Chu
2021-11-25 0:16 ` Dan Williams
2021-11-30 23:00 ` Jane Chu
2021-09-30 18:15 ` Jane Chu
2021-09-30 19:11 ` Dan Williams
2021-09-30 21:23 ` Jane Chu
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