Commit 1dc6ff02 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Thomas Gleixner
Browse files

x86/speculation/mmio: Print SMT warning 



Similar to MDS and TAA, print a warning if SMT is enabled for the MMIO
Stale Data vulnerability.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 027bbb88

arch/x86/kernel/cpu/bugs.c

+11 −0
Original line number Diff line number Diff line
@@ -1258,6 +1258,7 @@ static void update_mds_branch_idle(void) 


#define MDS_MSG_SMT "MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html for more details.\n"

#define TAA_MSG_SMT "TAA CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html for more details.\n"

#define MMIO_MSG_SMT "MMIO Stale Data CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/processor_mmio_stale_data.html for more details.\n"



void cpu_bugs_smt_update(void)

{
@@ -1302,6 +1303,16 @@ void cpu_bugs_smt_update(void) 
		break;

	}



	switch (mmio_mitigation) {

	case MMIO_MITIGATION_VERW:

	case MMIO_MITIGATION_UCODE_NEEDED:

		if (sched_smt_active())

			pr_warn_once(MMIO_MSG_SMT);

		break;

	case MMIO_MITIGATION_OFF:

		break;

	}



	mutex_unlock(&spec_ctrl_mutex);

}