Commit 0cdd2c4f authored by David Kaplan's avatar David Kaplan Committed by Borislav Petkov (AMD)
Browse files

x86/bugs: Add attack vector controls for ITS 



Use attack vector controls to determine if ITS mitigation is required.

Signed-off-by: default avatarDavid Kaplan <david.kaplan@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-19-david.kaplan@amd.com
parent eda718fd

arch/x86/kernel/cpu/bugs.c

+10 −5
Original line number Diff line number Diff line
@@ -1518,13 +1518,17 @@ early_param("indirect_target_selection", its_parse_cmdline); 


static void __init its_select_mitigation(void)

{

	if (!boot_cpu_has_bug(X86_BUG_ITS) || cpu_mitigations_off()) {

	if (!boot_cpu_has_bug(X86_BUG_ITS)) {

		its_mitigation = ITS_MITIGATION_OFF;

		return;

	}



	if (its_mitigation == ITS_MITIGATION_AUTO)

	if (its_mitigation == ITS_MITIGATION_AUTO) {

		if (should_mitigate_vuln(X86_BUG_ITS))

			its_mitigation = ITS_MITIGATION_ALIGNED_THUNKS;

		else

			its_mitigation = ITS_MITIGATION_OFF;

	}



	if (its_mitigation == ITS_MITIGATION_OFF)

		return;
@@ -1555,11 +1559,12 @@ static void __init its_select_mitigation(void) 


static void __init its_update_mitigation(void)

{

	if (!boot_cpu_has_bug(X86_BUG_ITS) || cpu_mitigations_off())

	if (!boot_cpu_has_bug(X86_BUG_ITS))

		return;



	switch (spectre_v2_enabled) {

	case SPECTRE_V2_NONE:

		if (its_mitigation != ITS_MITIGATION_OFF)

			pr_err("WARNING: Spectre-v2 mitigation is off, disabling ITS\n");

		its_mitigation = ITS_MITIGATION_OFF;

		break;