On Sun, Jul 01, 2018 at 12:19:22PM +0200, Maxime Villard wrote: > Pay attention to 325384-sdm-vol-3abcd.pdf, page 1314/2008: > > "If the SSE3 feature flag ECX[0] is not set (CPUID.01H:ECX[bit 0] = 0), > the OS must not attempt to alter this bit. BIOS must leave it in the > default state. Writing this bit when the SSE3 feature flag is set to > 0 may generate a #GP exception." > > Are you sure the affected family-model-stepping CPUs have the SSE3 feature > flag? Because if they don't you can't clear the bit.
I'll try to check for extra verification. > Otherwise it doesn't look incorrect to me. However you may want to reapply the > wrmsr after an ACPI wakeup, because chances are it got reset. But I guess it > doesn't matter a lot since there are countless MSRs we don't reapply, so it's > not like it's not already broken. I actually don't rely on wrmsr, we check everywhere for cpu_feature or similar, but it felt error-prone to leave it as-is.
