From 809f1845cf76023f97b8f9c03dd8e10fdda2aac6 Mon Sep 17 00:00:00 2001 From: "Chang S. Bae" Date: Fri, 15 Mar 2024 23:05:34 -0700 Subject: [PATCH v6a 3/7] x86/microcode/intel: Establish staging control logic When microcode staging is initiated, operations are carried out through an MMIO interface. Each package has a unique interface specified by the IA32_MCU_STAGING_MBOX_ADDR MSR, which maps to a set of 32-bit registers. Prepare staging with the following steps: 1. Ensure the microcode image is 32-bit aligned to match the MMIO register size. 2. Identify each MMIO interface based on its per-package scope. 3. Invoke the staging function for each identified interface, which will be implemented separately. Suggested-by: Thomas Gleixner Signed-off-by: Chang S. Bae Tested-by: Anselm Busse Reviewed-by: Tony Luck Link: https://lore.kernel.org/all/871pznq229.ffs@tglx --- V6 -> V6a: * Add an error message for misaligned image size (Boris) * Fix typo: id -> ID (Boris) * Shorten the error code printout (Boris) --- arch/x86/include/asm/msr-index.h | 2 ++ arch/x86/kernel/cpu/microcode/intel.c | 51 +++++++++++++++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 718a55d82fe4..0736e44f7c69 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -1222,6 +1222,8 @@ #define MSR_IA32_VMX_VMFUNC 0x00000491 #define MSR_IA32_VMX_PROCBASED_CTLS3 0x00000492 +#define MSR_IA32_MCU_STAGING_MBOX_ADDR 0x000007a5 + /* Resctrl MSRs: */ /* - Intel: */ #define MSR_IA32_L3_QOS_CFG 0xc81 diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 371ca6eac00e..216595a45564 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -299,6 +299,56 @@ static __init struct microcode_intel *scan_microcode(void *data, size_t size, return size ? NULL : patch; } +/* + * Handle the staging process using the mailbox MMIO interface. + * Return 0 on success or an error code on failure. + */ +static int do_stage(u64 mmio_pa) +{ + pr_debug_once("Staging implementation is pending.\n"); + return -EPROTONOSUPPORT; +} + +static void stage_microcode(void) +{ + unsigned int pkg_id = UINT_MAX; + int cpu, err; + u64 mmio_pa; + + if (!IS_ALIGNED(get_totalsize(&ucode_patch_late->hdr), sizeof(u32))) { + pr_err("Microcode image 32-bit misaligned (0x%x), staging failed.\n", + get_totalsize(&ucode_patch_late->hdr)); + return; + } + + lockdep_assert_cpus_held(); + + /* + * The MMIO address is unique per package, and all the SMT + * primary threads are online here. Find each MMIO space by + * their package IDs to avoid duplicate staging. + */ + for_each_cpu(cpu, cpu_primary_thread_mask) { + if (topology_logical_package_id(cpu) == pkg_id) + continue; + + pkg_id = topology_logical_package_id(cpu); + + err = rdmsrq_on_cpu(cpu, MSR_IA32_MCU_STAGING_MBOX_ADDR, &mmio_pa); + if (WARN_ON_ONCE(err)) + return; + + err = do_stage(mmio_pa); + if (err) { + pr_err("Error: staging failed (%d) for CPU%d at package %u.\n", + err, cpu, pkg_id); + return; + } + } + + pr_info("Staging of patch revision 0x%x succeeded.\n", ucode_patch_late->hdr.rev); +} + static enum ucode_state __apply_microcode(struct ucode_cpu_info *uci, struct microcode_intel *mc, u32 *cur_rev) @@ -627,6 +677,7 @@ static struct microcode_ops microcode_intel_ops = { .collect_cpu_info = collect_cpu_info, .apply_microcode = apply_microcode_late, .finalize_late_load = finalize_late_load, + .stage_microcode = stage_microcode, .use_nmi = IS_ENABLED(CONFIG_X86_64), }; -- 2.48.1