| Date | Thu, 4 Jan 2018 19:28:58 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 7/7] x86/microcode: Recheck IBRS features on microcode reload |
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On Thu, Jan 04, 2018 at 09:56:48AM -0800, Tim Chen wrote: > 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);
No need for that - make a specific function like perf_check_microcode() which checks only the IBRS bit and updates stuff accordingly.
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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