| From | Tim Chen <> | Subject | [PATCH 7/7] x86/microcode: Recheck IBRS features on microcode reload | Date | Thu, 4 Jan 2018 09:56:48 -0800 |
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On new microcode write, check whether IBRS is present by rescanning scattered CPU features.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> --- arch/x86/kernel/cpu/microcode/core.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index c4fa4a8..44b9355 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -40,6 +40,7 @@ #include <asm/processor.h> #include <asm/cmdline.h> #include <asm/setup.h> +#include <asm/spec_ctrl.h> #define DRIVER_VERSION "2.2" @@ -444,6 +445,11 @@ static ssize_t microcode_write(struct file *file, const char __user *buf, if (ret > 0) perf_check_microcode(); + /* check spec_ctrl capabilities */ + mutex_lock(&spec_ctrl_mutex); + init_scattered_cpuid_features(&boot_cpu_data); + mutex_unlock(&spec_ctrl_mutex); + mutex_unlock(µcode_mutex); put_online_cpus(); -- 2.9.4
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