[PATCH 4.14 095/138] x86/microcode: Attempt late loading only when new microcode is present

4.14-stable review patch. If anyone has any objections, please let me know.

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From: Borislav Petkov bp@suse.de

commit 2613f36ed965d0e5a595a1d931fd3b480e82d6fd upstream.

Return UCODE_NEW from the scanning functions to denote that new microcode was found and only then attempt the expensive synchronization dance.

Reported-by: Emanuel Czirai xftroxgpx@protonmail.com Signed-off-by: Borislav Petkov bp@suse.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: Emanuel Czirai xftroxgpx@protonmail.com Tested-by: Ashok Raj ashok.raj@intel.com Tested-by: Tom Lendacky thomas.lendacky@amd.com Link: https://lkml.kernel.org/r/20180314183615.17629-1-bp@alien8.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/include/asm/microcode.h | 1 + arch/x86/kernel/cpu/microcode/amd.c | 34 +++++++++++++++++++++------------- arch/x86/kernel/cpu/microcode/core.c | 8 +++----- arch/x86/kernel/cpu/microcode/intel.c | 4 +++- 4 files changed, 28 insertions(+), 19 deletions(-)

--- a/arch/x86/include/asm/microcode.h +++ b/arch/x86/include/asm/microcode.h @@ -39,6 +39,7 @@ struct device;

enum ucode_state { UCODE_OK = 0, + UCODE_NEW, UCODE_UPDATED, UCODE_NFOUND, UCODE_ERROR, --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -339,7 +339,7 @@ int __init save_microcode_in_initrd_amd( return -EINVAL;

ret = load_microcode_amd(true, x86_family(cpuid_1_eax), desc.data, desc.size); - if (ret != UCODE_OK) + if (ret > UCODE_UPDATED) return -EINVAL;

return 0; @@ -683,27 +683,35 @@ static enum ucode_state __load_microcode static enum ucode_state load_microcode_amd(bool save, u8 family, const u8 *data, size_t size) { + struct ucode_patch *p; enum ucode_state ret;

/* free old equiv table */ free_equiv_cpu_table();

ret = __load_microcode_amd(family, data, size); - - if (ret != UCODE_OK) + if (ret != UCODE_OK) { cleanup(); + return ret; + }

-#ifdef CONFIG_X86_32 - /* save BSP's matching patch for early load */ - if (save) { - struct ucode_patch *p = find_patch(0); - if (p) { - memset(amd_ucode_patch, 0, PATCH_MAX_SIZE); - memcpy(amd_ucode_patch, p->data, min_t(u32, ksize(p->data), - PATCH_MAX_SIZE)); - } + p = find_patch(0); + if (!p) { + return ret; + } else { + if (boot_cpu_data.microcode == p->patch_id) + return ret; + + ret = UCODE_NEW; } -#endif + + /* save BSP's matching patch for early load */ + if (!save) + return ret; + + memset(amd_ucode_patch, 0, PATCH_MAX_SIZE); + memcpy(amd_ucode_patch, p->data, min_t(u32, ksize(p->data), PATCH_MAX_SIZE)); + return ret; }

--- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -607,7 +607,7 @@ static ssize_t reload_store(struct devic return size;

tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true); - if (tmp_ret != UCODE_OK) + if (tmp_ret != UCODE_NEW) return size;

get_online_cpus(); @@ -691,10 +691,8 @@ static enum ucode_state microcode_init_c if (system_state != SYSTEM_RUNNING) return UCODE_NFOUND;

- ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, - refresh_fw); - - if (ustate == UCODE_OK) { + ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, refresh_fw); + if (ustate == UCODE_NEW) { pr_debug("CPU%d updated upon init\n", cpu); apply_microcode_on_target(cpu); } --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -862,6 +862,7 @@ static enum ucode_state generic_load_mic unsigned int leftover = size; unsigned int curr_mc_size = 0, new_mc_size = 0; unsigned int csig, cpf; + enum ucode_state ret = UCODE_OK;

while (leftover) { struct microcode_header_intel mc_header; @@ -903,6 +904,7 @@ static enum ucode_state generic_load_mic new_mc = mc; new_mc_size = mc_size; mc = NULL; /* trigger new vmalloc */ + ret = UCODE_NEW; }

ucode_ptr += mc_size; @@ -932,7 +934,7 @@ static enum ucode_state generic_load_mic pr_debug("CPU%d found a matching microcode update with version 0x%x (current=0x%x)\n", cpu, new_rev, uci->cpu_sig.rev);

- return UCODE_OK; + return ret; }

static int get_ucode_fw(void *to, const void *from, size_t n)