Re: [PATCH v12 1/8] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking - Yu, Yu-cheng

From: "Yu, Yu-cheng" <yu-cheng.yu@intel.com>
To: Dave Hansen <dave.hansen@intel.com>, Pavel Machek <pavel@ucw.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-mm@kvack.org, linux-arch@vger.kernel.org,
	linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Andy Lutomirski <luto@kernel.org>,
	Balbir Singh <bsingharora@gmail.com>,
	Borislav Petkov <bp@alien8.de>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Eugene Syromiatnikov <esyr@redhat.com>,
	Florian Weimer <fweimer@redhat.com>,
	"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Kees Cook <keescook@chromium.org>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Nadav Amit <nadav.amit@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
	Dave Martin <Dave.Martin@arm.com>,
	Weijiang Yang <weijiang.yang@intel.com>
Subject: Re: [PATCH v12 1/8] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking
Date: Mon, 21 Sep 2020 16:27:55 -0700	[thread overview]
Message-ID: <5e0a4005-45e3-3e88-e6e0-4ec31aad7eb9@intel.com> (raw)
In-Reply-To: <9cf234db-d0f7-0466-be2c-afe04eb76759@intel.com>

On 9/21/2020 3:54 PM, Dave Hansen wrote:
> On 9/21/20 3:47 PM, Yu, Yu-cheng wrote:
>>> The 900KB is probably wrong today in a lot of configurations, and will;
>>> only get *more* wrong over time.
>>
>> I was talking about the vmlinux file, and probably should have said
>> bzImage size, which has 14 KB increase when CET is enabled.
> 
> Well, vmlinux size is important too.  1 page of vmlinux size means one
> fewer page of memory available for real use.
> 
> I would really encourage you when you write to try to be specific and
> use as much plain language as possible without being verbose.  Most
> people understand things like "this feature increases kernel text size".
>   I wouldn't expect most folks who can type "make oldconfig; make
> install" to understands the difference between vmlinux and bzImage.
> 

Ok, thanks!

Yu-cheng