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Commit 12a0dad7 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Greg Kroah-Hartman
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x86/speculation/mds: Add 'mitigations=' support for MDS 



commit 5c14068f87d04adc73ba3f41c2a303d3c3d1fa12 upstream

Add MDS to the new 'mitigations=' cmdline option.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 59a14fb5

Documentation/admin-guide/kernel-parameters.txt

+2 −0
Original line number Diff line number Diff line
@@ -2519,6 +2519,7 @@ 
					       spectre_v2_user=off [X86]

					       spec_store_bypass_disable=off [X86,PPC]

					       l1tf=off [X86]

					       mds=off [X86]



			auto (default)

				Mitigate all CPU vulnerabilities, but leave SMT
@@ -2533,6 +2534,7 @@ 
				if needed.  This is for users who always want to

				be fully mitigated, even if it means losing SMT.

				Equivalent to: l1tf=flush,nosmt [X86]

					       mds=full,nosmt [X86]



	mminit_loglevel=

			[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this

arch/x86/kernel/cpu/bugs.c

+3 −2
Original line number Diff line number Diff line
@@ -231,7 +231,7 @@ static const char * const mds_strings[] = { 


static void __init mds_select_mitigation(void)

{

	if (!boot_cpu_has_bug(X86_BUG_MDS)) {

	if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) {

		mds_mitigation = MDS_MITIGATION_OFF;

		return;

	}
@@ -242,7 +242,8 @@ static void __init mds_select_mitigation(void) 


		static_branch_enable(&mds_user_clear);



		if (mds_nosmt && !boot_cpu_has(X86_BUG_MSBDS_ONLY))

		if (!boot_cpu_has(X86_BUG_MSBDS_ONLY) &&

		    (mds_nosmt || cpu_mitigations_auto_nosmt()))

			cpu_smt_disable(false);

	}