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Message-ID: <27da7cf5-5ff4-a10c-a506-de77aeff8dd6@amd.com>
Date: Tue, 14 Apr 2020 15:16:18 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: Dave Hansen <dave.hansen@...el.com>,
Mike Stunes <mstunes@...are.com>,
Joerg Roedel <joro@...tes.org>
Cc: "x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>,
Andy Lutomirski <luto@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Hellstrom <thellstrom@...are.com>,
Jiri Slaby <jslaby@...e.cz>,
Dan Williams <dan.j.williams@...el.com>,
Juergen Gross <jgross@...e.com>,
Kees Cook <keescook@...omium.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"virtualization@...ts.linux-foundation.org"
<virtualization@...ts.linux-foundation.org>,
Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH 40/70] x86/sev-es: Setup per-cpu GHCBs for the runtime
handler
On 4/14/20 3:12 PM, Dave Hansen wrote:
> On 4/14/20 1:04 PM, Tom Lendacky wrote:
>>> set_memory_decrypted needs to check the return value. I see it
>>> consistently return ENOMEM. I've traced that back to split_large_page
>>> in arch/x86/mm/pat/set_memory.c.
>>
>> At that point the guest won't be able to communicate with the
>> hypervisor, too. Maybe we should BUG() here to terminate further
>> processing?
>
> Escalating an -ENOMEM into a crashed kernel seems a bit extreme.
> Granted, the guest may be in an unrecoverable state, but the host
> doesn't need to be too.
>
The host wouldn't be. This only happens in a guest, so it would be just
causing the guest kernel to panic early in the boot.
Thanks,
Tom
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