From 9a819753b0209c6edebdea447a1aa53e8c697653 Mon Sep 17 00:00:00 2001 From: "Chang S. Bae" Date: Tue, 1 Oct 2024 09:10:36 -0700 Subject: x86/microcode/intel: Remove unnecessary cache writeback and invalidation Currently, an unconditional cache flush is performed during every microcode update. Although the original changelog did not mention a specific erratum, this measure was primarily intended to address a specific microcode bug, the load of which has already been blocked by is_blacklisted(). Therefore, this cache flush is no longer necessary. Additionally, the side effects of doing this have been overlooked. It increases CPU rendezvous time during late loading, where the cache flush takes between 1x to 3.5x longer than the actual microcode update. Remove native_wbinvd() and update the erratum name to align with the latest errata documentation, document ID 334163 Version 022US. [ bp: Zap the flaky documentation URL. ] Fixes: 91df9fdf5149 ("x86/microcode/intel: Writeback and invalidate caches before updating microcode") Reported-by: Yan Hua Wu Reported-by: William Xie Signed-off-by: Chang S. Bae Signed-off-by: Borislav Petkov (AMD) Acked-by: Ashok Raj Tested-by: Yan Hua Wu Link: https://lore.kernel.org/r/20241001161042.465584-2-chang.seok.bae@intel.com --- arch/x86/kernel/cpu/microcode/intel.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 815fa67356a2..f3d534807d91 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -319,12 +319,6 @@ static enum ucode_state __apply_microcode(struct ucode_cpu_info *uci, return UCODE_OK; } - /* - * Writeback and invalidate caches before updating microcode to avoid - * internal issues depending on what the microcode is updating. - */ - native_wbinvd(); - /* write microcode via MSR 0x79 */ native_wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits); @@ -574,14 +568,14 @@ static bool is_blacklisted(unsigned int cpu) /* * Late loading on model 79 with microcode revision less than 0x0b000021 * and LLC size per core bigger than 2.5MB may result in a system hang. - * This behavior is documented in item BDF90, #334165 (Intel Xeon + * This behavior is documented in item BDX90, #334165 (Intel Xeon * Processor E7-8800/4800 v4 Product Family). */ if (c->x86_vfm == INTEL_BROADWELL_X && c->x86_stepping == 0x01 && llc_size_per_core > 2621440 && c->microcode < 0x0b000021) { - pr_err_once("Erratum BDF90: late loading with revision < 0x0b000021 (0x%x) disabled.\n", c->microcode); + pr_err_once("Erratum BDX90: late loading with revision < 0x0b000021 (0x%x) disabled.\n", c->microcode); pr_err_once("Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); return true; } -- cgit v1.2.3 From c809b0d0e52d01c30066367b2952c4c4186b1047 Mon Sep 17 00:00:00 2001 From: "Borislav Petkov (AMD)" Date: Tue, 19 Nov 2024 12:21:33 +0100 Subject: x86/microcode/AMD: Flush patch buffer mapping after application Due to specific requirements while applying microcode patches on Zen1 and 2, the patch buffer mapping needs to be flushed from the TLB after application. Do so. If not, unnecessary and unnatural delays happen in the boot process. Reported-by: Thomas De Schampheleire Signed-off-by: Borislav Petkov (AMD) Tested-by: Thomas De Schampheleire Cc: # f1d84b59cbb9 ("x86/mm: Carve out INVLPG inline asm for use by others") Link: https://lore.kernel.org/r/ZyulbYuvrkshfsd2@antipodes --- arch/x86/kernel/cpu/microcode/amd.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 31a73715d755..fb5d0c67fbab 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -34,6 +34,7 @@ #include #include #include +#include #include "internal.h" @@ -483,11 +484,25 @@ static void scan_containers(u8 *ucode, size_t size, struct cont_desc *desc) } } -static int __apply_microcode_amd(struct microcode_amd *mc) +static int __apply_microcode_amd(struct microcode_amd *mc, unsigned int psize) { + unsigned long p_addr = (unsigned long)&mc->hdr.data_code; u32 rev, dummy; - native_wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc->hdr.data_code); + native_wrmsrl(MSR_AMD64_PATCH_LOADER, p_addr); + + if (x86_family(bsp_cpuid_1_eax) == 0x17) { + unsigned long p_addr_end = p_addr + psize - 1; + + invlpg(p_addr); + + /* + * Flush next page too if patch image is crossing a page + * boundary. + */ + if (p_addr >> PAGE_SHIFT != p_addr_end >> PAGE_SHIFT) + invlpg(p_addr_end); + } /* verify patch application was successful */ native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy); @@ -529,7 +544,7 @@ static bool early_apply_microcode(u32 old_rev, void *ucode, size_t size) if (old_rev > mc->hdr.patch_id) return ret; - return !__apply_microcode_amd(mc); + return !__apply_microcode_amd(mc, desc.psize); } static bool get_builtin_microcode(struct cpio_data *cp) @@ -745,7 +760,7 @@ void reload_ucode_amd(unsigned int cpu) rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy); if (rev < mc->hdr.patch_id) { - if (!__apply_microcode_amd(mc)) + if (!__apply_microcode_amd(mc, p->size)) pr_info_once("reload revision: 0x%08x\n", mc->hdr.patch_id); } } @@ -798,7 +813,7 @@ static enum ucode_state apply_microcode_amd(int cpu) goto out; } - if (__apply_microcode_amd(mc_amd)) { + if (__apply_microcode_amd(mc_amd, p->size)) { pr_err("CPU%d: update failed for patch_level=0x%08x\n", cpu, mc_amd->hdr.patch_id); return UCODE_ERROR; -- cgit v1.2.3