Pawan Gupta 8b5760939d x86/mmio: Disable KVM mitigation when X86_FEATURE_CLEAR_CPU_BUF is set
commit e95df4ec0c0c9791941f112db699fae794b9862a upstream.

Currently MMIO Stale Data mitigation for CPUs not affected by MDS/TAA is
to only deploy VERW at VMentry by enabling mmio_stale_data_clear static
branch. No mitigation is needed for kernel->user transitions. If such
CPUs are also affected by RFDS, its mitigation may set
X86_FEATURE_CLEAR_CPU_BUF to deploy VERW at kernel->user and VMentry.
This could result in duplicate VERW at VMentry.

Fix this by disabling mmio_stale_data_clear static branch when
X86_FEATURE_CLEAR_CPU_BUF is enabled.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-15 10:48:20 -04:00
..
2023-09-13 09:42:21 +02:00
2024-03-06 14:45:11 +00:00
2023-11-20 11:52:07 +01:00
2024-02-23 09:12:38 +01:00