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Message-ID: <20130103174455.GA7350@localhost.localdomain> Date: Thu, 3 Jan 2013 12:44:57 -0500 From: Konrad Rzeszutek Wilk <konrad@...nel.org> To: Fenghua Yu <fenghua.yu@...el.com> Cc: H Peter Anvin <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>, Asit K Mallick <asit.k.mallick@...el.com>, Tigran Aivazian <tigran@...azian.fsnet.co.uk>, Yinghai Lu <yinghai@...nel.org>, Andreas Herrmann <andreas.herrmann3@....com>, Borislav Petkov <borislav.petkov@....com>, linux-kernel <linux-kernel@...r.kernel.org>, x86 <x86@...nel.org> Subject: Re: [PATCH v5 00/12] x86/microcode: Early load microcode On Thu, Dec 20, 2012 at 11:44:20PM -0800, Fenghua Yu wrote: > From: Fenghua Yu <fenghua.yu@...el.com> > > The problem in current microcode loading method is that we load a microcode way, > way too late; ideally we should load it before turning paging on. This may only > be practical on 32 bits since we can't get to 64-bit mode without paging on, > but we should still do it as early as at all possible. > > Similarly, we should load the microcode update as early as possible during AP > bringup and when processors are brought back online after hotplug or S3/S4. > > In order to do that, the microcode patch needs to be permanently present in > kernel memory. Each individual patch is fairly small, so that is OK, but the > entire blob with support for each CPU is too big. Since only CPU's with same > model can be in the same platform, we store microcode with the same model as > BSP. Later on APs can upload microcode from the saved microcodep patches. > > Note, however, that Linux users have gotten used to being able to install a > microcode patch in the field without having a reboot; we support that model too. > > In x86_64, this patchset needs early #PF handler set page table patchset. So > this patchset is based on: > git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-x86-boot > A couple of questions - why the usage of native_[read|write]_msr? I get the __native_cpuid variant, but I am not sure I understand why you are using the native_* variants. Especially as this code ends up being called on Xen and lguest (at least on 64-bit) and probably should go through the paravirt interfaces. Also the same question for the __native_flush_tlb_global_irq_disabled - you take parts of it out (the ones dealing with CR4) and end up calling those directly? Should they perhaps go through the paravirt interface? > v5: Call 64 bit load_ucode_bsp() after copy_bootdata() and remove its > parameter. > > v4: Change CPUID_IS macro. Call load_ucode_bsp after load_idt in x86_64. Flush > tlb after applying microcode. > > v3: Change .hex to .bin in 01/10 and 05/10 patches. Fix some compilation > warnings. In x86_32 mode, access global varialbes by __pa_symobl() and fix > static string issue in x86_vendor(). Call load_ucode_ap() in real mode as well. > Add debug info. > > v2: Detect vendor before loading microcode. Move some functions from > microcode_intel_early.c to microcode_intel_lib.c. Change some early loading > microcode dependencies in Kconfig. Reword doc. > > Fenghua Yu (12): > Documentation/x86: Early load microcode > x86/microcode_intel.h: Define functions and macros for early loading > ucode > x86/common.c: Make have_cpuid_p() a global function > x86/common.c: load ucode in 64 bit or show loading ucode info in 32 > bit on AP > x86/microcode_core_early.c: Define interfaces for early loading ucode > x86/microcode_intel_lib.c: Early update ucode on Intel's CPU > x86/tlbflush.h: Define __native_flush_tlb_global_irq_disabled() > x86/microcode_intel_early.c: Early update ucode on Intel's CPU > x86/head_32.S: Early update ucode in 32-bit > x86/head64.c: Early update ucode in 64-bit > x86/mm/init.c: Copy ucode from initrd image to kernel memory > x86/Kconfig: Configurations to enable/disable the feature > > Documentation/x86/early-microcode.txt | 43 ++ > arch/x86/Kconfig | 18 + > arch/x86/include/asm/microcode.h | 14 + > arch/x86/include/asm/microcode_intel.h | 85 ++++ > arch/x86/include/asm/processor.h | 8 + > arch/x86/include/asm/tlbflush.h | 18 +- > arch/x86/kernel/Makefile | 3 + > arch/x86/kernel/cpu/common.c | 17 +- > arch/x86/kernel/head64.c | 6 + > arch/x86/kernel/head_32.S | 11 + > arch/x86/kernel/microcode_core.c | 7 +- > arch/x86/kernel/microcode_core_early.c | 76 +++ > arch/x86/kernel/microcode_intel.c | 198 ++------ > arch/x86/kernel/microcode_intel_early.c | 796 ++++++++++++++++++++++++++++++++ > arch/x86/kernel/microcode_intel_lib.c | 174 +++++++ > arch/x86/mm/init.c | 10 + > 16 files changed, 1301 insertions(+), 183 deletions(-) > create mode 100644 Documentation/x86/early-microcode.txt > create mode 100644 arch/x86/include/asm/microcode_intel.h > create mode 100644 arch/x86/kernel/microcode_core_early.c > create mode 100644 arch/x86/kernel/microcode_intel_early.c > create mode 100644 arch/x86/kernel/microcode_intel_lib.c > > -- > 1.8.0.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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