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Date:   Mon, 16 Nov 2020 21:17:11 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Alexandre Chartre <alexandre.chartre@oracle.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
        x86@kernel.org, dave.hansen@linux.intel.com, luto@kernel.org,
        peterz@infradead.org, linux-kernel@vger.kernel.org,
        thomas.lendacky@amd.com, jroedel@suse.de, konrad.wilk@oracle.com,
        jan.setjeeilers@oracle.com, junaids@google.com, oweisse@google.com,
        rppt@linux.vnet.ibm.com, graf@amazon.de, mgross@linux.intel.com,
        kuzuno@gmail.com
Subject: Re: [RFC][PATCH v2 00/21] x86/pti: Defer CR3 switch to C code
Message-ID: <20201116201711.GE1131@zn.tnic>
References: <20201116144757.1920077-1-alexandre.chartre@oracle.com>
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On Mon, Nov 16, 2020 at 03:47:36PM +0100, Alexandre Chartre wrote:
> This RFC proposes to defer the PTI CR3 switch until we reach C code.
> The benefit is that this simplifies the assembly entry code, and make
> the PTI CR3 switch code easier to understand. This also paves the way
> for further possible projects such an easier integration of Address
> Space Isolation (ASI), or the possibilily to execute some selected
> syscall or interrupt handlers without switching to the kernel page-table

What for? What is this going to be used for in the end?

> (and thus avoid the PTI page-table switch overhead).

Overhead of how much? Why do we care?

What is the big picture justfication for this diffstat

>  21 files changed, 874 insertions(+), 314 deletions(-)

and the diffstat for the ASI enablement?

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette