[PATCH] x86/microcode: add parameter dis_ucode_ldr in kernel-paramenters.txt

[PATCH] x86/microcode: add parameter dis_ucode_ldr in kernel-paramenters.txt

[Fenghua Yu]

From: Fenghua Yu <fenghua.yu@intel.com>

The kernel parameter dis_ucode_ldr disables early loading microcode from
initrd. The parameter was introduced earlier by Borislave Petkov.

This patch adds the explanation for this parameter in
Documentation/kernel-parameters.txt for user convenience.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
 Documentation/kernel-parameters.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 5ae8608..eef098f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -841,6 +841,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	dhash_entries=	[KNL]
 			Set number of hash buckets for dentry cache.
 
+	dis_ucode_ldr	[X86]
+			This parameter disables the early microcode loader.
+			This is useful mostly in debugging situations where
+			we want to turn off early microcode loading from the
+			initrd, as a means to be able to rule out its
+			influence on the machine.
+
 	disable=	[IPV6]
 			See Documentation/networking/ipv6.txt.
 
-- 
1.8.1.2

Re: [PATCH] x86/microcode: add parameter dis_ucode_ldr in kernel-paramenters.txt

[Borislav Petkov]

On Thu, Sep 04, 2014 at 12:07:06PM -0700, Fenghua Yu wrote:
> From: Fenghua Yu <fenghua.yu@intel.com>
> 
> The kernel parameter dis_ucode_ldr disables early loading microcode from
> initrd. The parameter was introduced earlier by Borislave Petkov.

My name is Borislav Petkov, without an "e".

> This patch adds the explanation for this parameter in
> Documentation/kernel-parameters.txt for user convenience.

As I said earlier, I don't want to do exactly that because this
parameter should be used only to rule out microcode loading causes a
problem and not regularly. I know, it doesn't stop people from looking
at the code but still.

So NAK.

-- 
Regards/Gruss,
    Boris.
--

Re: [PATCH] x86/microcode: add parameter dis_ucode_ldr in kernel-paramenters.txt

[H. Peter Anvin]

On 09/05/2014 01:57 AM, Borislav Petkov wrote:
> 
>> This patch adds the explanation for this parameter in
>> Documentation/kernel-parameters.txt for user convenience.
> 
> As I said earlier, I don't want to do exactly that because this
> parameter should be used only to rule out microcode loading causes a
> problem and not regularly. I know, it doesn't stop people from looking
> at the code but still.
> 

Are you genuinely saying we shouldn't document this command line
parameter?  Sorry, it really doesn't work that way.

	-hpa

Re: [PATCH] x86/microcode: add parameter dis_ucode_ldr in kernel-paramenters.txt

[Borislav Petkov]

On Mon, Sep 08, 2014 at 12:09:12PM -0700, H. Peter Anvin wrote:
> Are you genuinely saying we shouldn't document this command line
> parameter? Sorry, it really doesn't work that way.

My intent is to keep this one from getting abused for the wrong reasons.
Not documenting it is probably not going to get me that in the end,
though. Right.

-- 
Regards/Gruss,
    Boris.
--