Date: Fri, 15 Sep 2017 18:22:56 +0200
From: Borislav Petkov <bp@suse.de>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@arndb.de>,
        David Laight <David.Laight@aculab.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
        "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        David Howells <dhowells@redhat.com>, Paul Mackerras <paulus@samba.org>,
        Christoph Lameter <cl@linux.com>, Jonathan Corbet <corbet@lwn.net>,
        Radim =?utf-8?Q?Krcm=C3=A1r?= <rkrcmar@redhat.com>,
        Piotr Luc <piotr.luc@intel.com>, Ingo Molnar <mingo@redhat.com>,
        Dave Airlie <airlied@redhat.com>, Kees Cook <keescook@chromium.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Reza Arbab <arbab@linux.vnet.ibm.com>,
        Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Laura Abbott <labbott@redhat.com>, Tony Luck <tony.luck@intel.com>,
        Ard.Biesheuvel@zytor.com
Subject: Re: [RFC Part1 PATCH v3 13/17] x86/io: Unroll string I/O when SEV is
 active
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On Fri, Sep 15, 2017 at 09:48:53AM -0500, Brijesh Singh wrote:
> I see the similar issue with non SEV guest with my simple patch below.
> Guest will reboot as soon as it tries to enable the key.

Can't do it there as the pagetable is not setup yet and you're probably
getting a #PF on any of the derefs down the static_key_enable() path.

I guess one possible place to enable the static key would be in
mem_encrypt_init() where everything should be set up already.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--