From: Andy Lutomirski <luto@kernel.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Joerg Roedel <jroedel@suse.de>,
David Rientjes <rientjes@google.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Jon Grimm <jon.grimm@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>, X86 ML <x86@kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: AMD SEV-SNP/Intel TDX: validation of memory pages
Date: Fri, 12 Feb 2021 14:46:41 -0800 [thread overview]
Message-ID: <CALCETrUSpwsWveGPFvyQmZ1H57H4WMhnTVVqnwPX8Xi4rqHqpg@mail.gmail.com> (raw)
In-Reply-To: <20210212223918.GG365765@tassilo.jf.intel.com>
On Fri, Feb 12, 2021 at 2:39 PM Andi Kleen <ak@linux.intel.com> wrote:
>
> > But AFAI recursive #VE is entirely possible. The moment #VE reads that
> > ve_info thing, NMIs can happen, which can trigger another #VE which then
> > clobbers your stack and we're irrecoverably screwed again.
>
> I don't believe we have anything currently in the NMI handler that
> would trigger #VE. While some operations may need TDCALL (like MSR
> accesses) those should be all directly hooked.
>
> Also in general to avoid clobbering your stack you would just need
> to make sure to adjust the IST stack before you do anything that
> could cause another #VE.
Except that the world contains more than just #VE. We could get #VE
and then NMI and then #VE or #VE and MCE (in a future revision?), etc.
The x86 exception situation is a mess.
next prev parent reply other threads:[~2021-02-12 22:46 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 1:51 David Rientjes
2021-02-02 13:17 ` Matthew Wilcox
2021-02-02 16:02 ` Kirill A. Shutemov
2021-02-03 0:16 ` Brijesh Singh
2021-02-11 17:46 ` Sean Christopherson
2021-02-02 22:37 ` Andi Kleen
2021-02-11 20:46 ` Peter Zijlstra
2021-02-12 13:19 ` Joerg Roedel
2021-02-12 14:17 ` Peter Zijlstra
2021-02-12 14:53 ` Joerg Roedel
2021-02-12 15:19 ` Peter Zijlstra
2021-02-12 15:28 ` Joerg Roedel
2021-02-12 16:12 ` Peter Zijlstra
2021-02-12 16:18 ` Joerg Roedel
2021-02-12 16:45 ` Peter Zijlstra
2021-02-12 17:48 ` Dave Hansen
2021-02-12 18:22 ` Sean Christopherson
2021-02-12 18:38 ` Andy Lutomirski
2021-02-12 18:43 ` Sean Christopherson
2021-02-12 18:46 ` Dave Hansen
2021-02-12 19:24 ` Sean Christopherson
2021-02-16 10:00 ` Joerg Roedel
2021-02-16 14:27 ` Andi Kleen
2021-02-16 14:46 ` Peter Zijlstra
2021-02-16 15:59 ` Paolo Bonzini
2021-02-16 16:25 ` Joerg Roedel
2021-02-16 16:48 ` Paolo Bonzini
2021-02-16 18:26 ` Joerg Roedel
2021-02-16 18:33 ` Paolo Bonzini
2021-02-16 16:47 ` Peter Zijlstra
2021-02-16 16:57 ` Andy Lutomirski
2021-02-16 17:05 ` Paolo Bonzini
2021-02-16 16:55 ` Andi Kleen
2021-02-12 21:42 ` Andi Kleen
2021-02-12 21:58 ` Peter Zijlstra
2021-02-12 22:39 ` Andi Kleen
2021-02-12 22:46 ` Andy Lutomirski [this message]
2021-02-13 9:38 ` Peter Zijlstra
2021-02-12 23:51 ` Paolo Bonzini
2021-03-23 9:33 ` Joerg Roedel
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