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From: Borislav Petkov <bp@alien8.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
	x86@kernel.org, nvdimm@lists.linux.dev,
	linux-cxl@vger.kernel.org, peterz@infradead.org,
	akpm@linux-foundation.org, dave.jiang@intel.com,
	Jonathan.Cameron@huawei.com, vishal.l.verma@intel.com,
	ira.weiny@intel.com, a.manzanares@samsung.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next] memregion: Add arch_flush_memregion() interface
Date: Thu, 8 Sep 2022 06:35:12 +0200	[thread overview]
Message-ID: <YxlxAFgW65w8wgPy@nazgul.tnic> (raw)
In-Reply-To: <6318cc415161f_166f2941e@dwillia2-xfh.jf.intel.com.notmuch>

On Wed, Sep 07, 2022 at 09:52:17AM -0700, Dan Williams wrote:
> To be clear nfit stuff and CXL does run in guests, but they do not
> support secure-erase in a guest.
> 
> However, the QEMU CXL enabling is building the ability to do *guest
> physical* address space management, but in that case the driver can be
> paravirtualized to realize that it is not managing host-physical address
> space and does not need to flush caches. That will need some indicator
> to differentiate virtual CXL memory expanders from assigned devices.

Sounds to me like that check should be improved later to ask
whether the kernel is managing host-physical address space, maybe
arch_flush_memregion() should check whether the address it is supposed
to flush is host-physical and exit early if not...

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  parent reply	other threads:[~2022-09-08  4:35 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-29 21:29 [PATCH -next] memregion: Add arch_flush_memregion() interface Davidlohr Bueso
2022-08-29 23:02 ` Dan Williams
2022-09-07 14:36 ` Davidlohr Bueso
2022-09-07 16:46   ` Dan Williams
2022-09-07 16:05 ` Borislav Petkov
2022-09-07 16:22   ` Davidlohr Bueso
2022-09-07 16:52     ` Dan Williams
2022-09-07 17:24       ` Davidlohr Bueso
2022-09-08  4:35       ` Borislav Petkov [this message]
2022-09-08  6:53         ` Dan Williams
2022-09-08 13:00           ` Jonathan Cameron
2022-09-08  4:31     ` Borislav Petkov
2022-09-07 22:30 ` Andrew Morton
2022-09-08  1:07   ` Dan Williams
2022-09-08 13:13     ` Jonathan Cameron
2022-09-08 22:51       ` Dan Williams
2022-09-08 23:00         ` Andrew Morton
2022-09-08 23:22           ` Dan Williams
2022-09-09 11:43             ` Jonathan Cameron
2022-09-13 15:56               ` Davidlohr Bueso

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