From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: Should SEV-ES #VC use IST? (Re: [PATCH] Allow RDTSC and RDTSCP
 from userspace)
Date: Tue, 23 Jun 2020 18:13:45 +0200
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To: Dave Hansen <dave.hansen@intel.com>
Cc: Juergen Gross <JGross@suse.com>, Tom Lendacky <Thomas.Lendacky@amd.com>, Thomas Hellstrom <thellstrom@vmware.com>, Joerg Roedel <jroedel@suse.de>, Mike Stunes <mstunes@vmware.com>, Kees Cook <keescook@chromium.org>, kvm list <kvm@vger.kernel.org>, Andrew Cooper <andrew.cooper3@citrix.com>, Joerg Roedel <joro@8bytes.org>, Dave Hansen <dave.hansen@linux.intel.com>, LKML <linux-kernel@vger.kernel.org>, Sean Christopherson <sean.j.christopherson@intel.com>, Linux Virtualization <virtualization@lists.linux-foundation.org>, Andy Lutomirski <luto@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, Dan Williams <dan.j.williams@intel.com>, Jiri Slaby <jslaby@suse.cz>, X86 ML <x86@kernel.org>
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On Tue, Jun 23, 2020 at 09:03:56AM -0700, Dave Hansen wrote:
> On 6/23/20 8:52 AM, Peter Zijlstra wrote:
> > Isn't current #MC unconditionally fatal from kernel? But yes, I was
> > sorta aware people want that changed.
> 
> Not unconditionally.  copy_to_iter_mcsafe() is a good example of one
> thing we _can_ handle.

Urgh, I thought that stuff was still pending.

Anyway, the important thing is that it is fatal if we hit early NMI.
Which I think still holds.