linux-kernel - Re: [PATCH] x86/mm: Don't try to change poison pages to uncacheable in a guest

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Message-ID: <20200516150229.GB19372@zn.tnic>
Date:   Sat, 16 May 2020 17:02:29 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     "Luck, Tony" <tony.luck@...el.com>
Cc:     Jue Wang <juew@...gle.com>,
        "Williams, Dan J" <dan.j.williams@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/mm: Don't try to change poison pages to uncacheable
 in a guest

On Sat, May 16, 2020 at 02:47:42PM +0000, Luck, Tony wrote:
> There is only one actual machine check. But the VMM simulates a second
> machine check to the guest when the guest tries to access the poisoned
> page.

If the VMM unmaps the bad page, why doesn't the guest get a #PF instead
injected by the VMM instead of latter injecting a second #MCE?

If the guest tries to access an unmapped page, it should get a #PF, I'd
expect.

-- 
Regards/Gruss,
    Boris.

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