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Message-ID: <2f24d157-8e8d-b632-0dc5-e082cf4ba8f4@intel.com>
Date:   Fri, 13 Jan 2023 11:39:48 -0800
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Subject: Re: [PATCH 5/7] x86/cpu: Enable LASS (Linear Address Space
 Separation)
Content-Language: en-US
From:   Sohil Mehta <sohil.mehta@intel.com>
To:     Dave Hansen <dave.hansen@intel.com>,
        Yian Chen <yian.chen@intel.com>,
        <linux-kernel@vger.kernel.org>, <x86@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Ravi Shankar <ravi.v.shankar@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Paul Lai <paul.c.lai@intel.com>,
        Kees Cook <keescook@chromium.org>,
        Florian Weimer <fweimer@redhat.com>,
        Borislav Petkov <bp@alien8.de>
References: <20230110055204.3227669-1-yian.chen@intel.com>
 <20230110055204.3227669-6-yian.chen@intel.com>
 <7e859e72-4624-73c7-8195-c252ace0a49d@intel.com>
 <f6d16f82-9cbe-993d-88aa-1644e89c4fe7@intel.com>
In-Reply-To: <f6d16f82-9cbe-993d-88aa-1644e89c4fe7@intel.com>
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Adding folks from the previous discussion when a similar suggestion was
made by Kees. There didn't seem to be any major objection that time.

https://lore.kernel.org/lkml/202205111424.DEB0E3418@keescook/

On 1/12/2023 5:17 PM, Sohil Mehta wrote:
> We can make CONFIG_LEGACY_VSYSCALL_NONE as the default instead of the
> current CONFIG_LEGACY_VSYSCALL_XONLY. The kernel can disable LASS at
> boot time if a user/admin has shown explicit preference by selecting
> CONFIG_LEGACY_VSYSCALL_XONLY or by providing command line parameter
> vsyscall=xonly/emulate.
> 
> Thoughts?