From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v4 51/75] x86/sev-es: Handle MMIO events
Date: Thu, 23 Jul 2020 09:21:02 +0200
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To: Mike Stunes <mstunes@vmware.com>
Cc: Joerg Roedel <jroedel@suse.de>, "x86@kernel.org" <x86@kernel.org>, Tom Lendacky <thomas.lendacky@amd.com>, "hpa@zytor.com" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>, Dave Hansen <dave.hansen@linux.intel.com>, Peter Zijlstra <peterz@infradead.org>, Jiri Slaby <jslaby@suse.cz>, Dan Williams <dan.j.williams@intel.com>, Juergen Gross <jgross@suse.com>, Kees Cook <keescook@chromium.org>, David Rientjes <rientjes@google.com>, Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>, Masami Hiramatsu <mhiramat@kernel.org>, Sean Christopherson <sean.j.christopherson@intel.com>, Martin Radev <martin.b.radev@gmail.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, virtualization@
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Hi Mike,

On Wed, Jul 22, 2020 at 10:53:02PM +0000, Mike Stunes wrote:
> Thanks Joerg! With that change in place, this kernel boots normally.
> What was the problem?

The problem was that the code got its page-table from
current->active_mm. But these pointers are not set up during early boot,
so that the #VC handler can't walk the page-table and propagates a
page-fault every time. This loops forever.

Getting the page-table from CR3 instead works at all stages of the
systems runtime.

Regards,

	Joerg