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| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2022-07-15 02:15:35 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-07-20 20:24:53 +0300 |
| commit | eb23b5ef9131e6d65011de349a4d25ef1b3d4314 (patch) | |
| tree | ecf5304ceb8f67c1a18be0710c4950efdea4819e /drivers/misc/lkdtm | |
| parent | 65cdf0d623bedf0e069bb64ed52e8bb20105e2ba (diff) | |
| download | linux-eb23b5ef9131e6d65011de349a4d25ef1b3d4314.tar.xz | |
x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts
IBRS mitigation for spectre_v2 forces write to MSR_IA32_SPEC_CTRL at
every kernel entry/exit. On Enhanced IBRS parts setting
MSR_IA32_SPEC_CTRL[IBRS] only once at boot is sufficient. MSR writes at
every kernel entry/exit incur unnecessary performance loss.
When Enhanced IBRS feature is present, print a warning about this
unnecessary performance loss.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/2a5eaf54583c2bfe0edc4fea64006656256cca17.1657814857.git.pawan.kumar.gupta@linux.intel.com
Diffstat (limited to 'drivers/misc/lkdtm')
0 files changed, 0 insertions, 0 deletions