On 10/13/2011 10:59 PM, Srivatsa S. Bhat wrote: > On 10/13/2011 10:31 PM, Borislav Petkov wrote: >> On Thu, Oct 13, 2011 at 12:06:02PM -0400, Tejun Heo wrote: >>> I hate to sound like a broken recorder but the above patch isn't >>> strictly correct for hot-swap cases, right? >> >> hpa is working on a ucode loading solution which will take care of your >> hotswap case too. >> > > Tejun, I have written a patch below (untested) that does what you said. > So Boris, hpa's work would make such a patch unnecessary is it? > I have posted this patch (tested/corrected and with changelog), in case it is useful/necessary. Link: https://lkml.org/lkml/2011/10/19/295 > --- > > arch/x86/kernel/microcode_core.c | 33 +++++++++++++++++++++++++++++++++ > 1 files changed, 33 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c > index f924280..849ae2d 100644 > --- a/arch/x86/kernel/microcode_core.c > +++ b/arch/x86/kernel/microcode_core.c > @@ -155,6 +155,27 @@ static int collect_cpu_info(int cpu) > return ret; > } > > +/* > + * Compare the microcode revision that the kernel has in memory > + * for this cpu and the microcode revision that we need to apply > + * on this cpu. If they match, return 0, else return -1. > + */ > +static int compare_cpu_with_microcode(int cpu) > +{ > + struct ucode_cpu_info *uci_mem = ucode_cpu_info + cpu; > + struct ucode_cpu_info uci_cpu; > + int ret; > + > + ret = collect_cpu_info_on_target(cpu, &uci_cpu->cpu_sig); > + if(!ret) { > + if (!(uci_mem->cpu_sig->sig == uci_cpu->cpu_sig->sig && > + uci_mem->cpu_sig->pf == uci_cpu->cpu_sig->pf && > + uci_mem->cpu_sig->rev == uci_cpu->cpu_sig->rev)) > + ret = -1; > + } > + return ret; > +} > + > struct apply_microcode_ctx { > int err; > }; > @@ -397,6 +418,18 @@ static enum ucode_state microcode_update_cpu(int cpu) > struct ucode_cpu_info *uci = ucode_cpu_info + cpu; > enum ucode_state ustate; > > + /* > + * If the CPU on which we are going to update the > + * microcode and the microcode which we currently > + * have in kernel memory are incompatible, then > + * invalidate the microcode that we have (and also > + * free its memory), so that we can get the required > + * microcode afresh. > + */ > + if (compare_cpu_with_microcode(cpu)) { > + microcode_fini_cpu(cpu); > + } > + > if (uci->valid) > ustate = microcode_resume_cpu(cpu); > else > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
