x86/microcode: Attempt late loading only when new microcode is present

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>

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 7fb1047..6cf0e4c 100644 (file)
--- 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,

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index a998e1a..4817992 100644 (file)
--- 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(unsigned int cpuid_1_eax)
                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_amd(u8 family, const u8 *data,
 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;
 }
 

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index bde629e..e6d5caa 100644 (file)
--- 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 device *dev,
                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_cpu(int cpu, bool refresh_fw)
        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);
        }

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 2aded9d..32b8e57 100644 (file)
--- 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_microcode(int cpu, void *data, size_t size,
        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_microcode(int cpu, void *data, size_t size,
                        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_microcode(int cpu, void *data, size_t size,
        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)