[Xen-devel] [PATCH v8 09/16] microcode: remove pointless 'cpu' parameter

[Chao Gao <chao.gao@xxxxxxxxx>]

Some callbacks in microcode_ops or related functions take a cpu
id parameter. But at current call sites, the cpu id parameter is
always equal to current cpu id. Some of them even use an assertion
to guarantee this. Remove this redundent 'cpu' parameter.

Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
---
Changes in v8:
 - Use current_cpu_data in collect_cpu_info()
 - keep the cpu parameter of check_final_patch_levels()
 - use smp_processor_id() in get_matching_microcode() rather than
 define a local variable and label it "__maybe_unused"
---
 xen/arch/x86/acpi/power.c       |  2 +-
 xen/arch/x86/microcode.c        | 20 ++++++++------------
 xen/arch/x86/microcode_amd.c    | 35 +++++++++++++----------------------
 xen/arch/x86/microcode_intel.c  | 28 ++++++++++------------------
 xen/arch/x86/smpboot.c          |  2 +-
 xen/include/asm-x86/microcode.h |  7 +++----
 xen/include/asm-x86/processor.h |  2 +-
 7 files changed, 37 insertions(+), 59 deletions(-)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index aecc754..4f21903 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -253,7 +253,7 @@ static int enter_state(u32 state)
 
     console_end_sync();
 
-    microcode_resume_cpu(0);
+    microcode_resume_cpu();
 
     if ( !recheck_cpu_features(0) )
         panic("Missing previously available feature(s)\n");
diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 9231dfb..bfb0afb 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -196,19 +196,19 @@ struct microcode_info {
     char buffer[1];
 };
 
-int microcode_resume_cpu(unsigned int cpu)
+int microcode_resume_cpu(void)
 {
     int err;
-    struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
+    struct cpu_signature *sig = &this_cpu(cpu_sig);
 
     if ( !microcode_ops )
         return 0;
 
     spin_lock(&microcode_mutex);
 
-    err = microcode_ops->collect_cpu_info(cpu, sig);
+    err = microcode_ops->collect_cpu_info(sig);
     if ( likely(!err) )
-        err = microcode_ops->apply_microcode(cpu);
+        err = microcode_ops->apply_microcode();
     spin_unlock(&microcode_mutex);
 
     return err;
@@ -258,9 +258,9 @@ static int microcode_update_cpu(const void *buf, size_t 
size)
 
     spin_lock(&microcode_mutex);
 
-    err = microcode_ops->collect_cpu_info(cpu, sig);
+    err = microcode_ops->collect_cpu_info(sig);
     if ( likely(!err) )
-        err = microcode_ops->cpu_request_microcode(cpu, buf, size);
+        err = microcode_ops->cpu_request_microcode(buf, size);
     spin_unlock(&microcode_mutex);
 
     return err;
@@ -349,8 +349,6 @@ __initcall(microcode_init);
 
 int __init early_microcode_update_cpu(bool start_update)
 {
-    unsigned int cpu = smp_processor_id();
-    struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
     int rc = 0;
     void *data = NULL;
     size_t len;
@@ -369,7 +367,7 @@ int __init early_microcode_update_cpu(bool start_update)
         data = bootstrap_map(&ucode_mod);
     }
 
-    microcode_ops->collect_cpu_info(cpu, sig);
+    microcode_ops->collect_cpu_info(&this_cpu(cpu_sig));
 
     if ( data )
     {
@@ -387,8 +385,6 @@ int __init early_microcode_update_cpu(bool start_update)
 
 int __init early_microcode_init(void)
 {
-    unsigned int cpu = smp_processor_id();
-    struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
     int rc;
 
     rc = microcode_init_intel();
@@ -401,7 +397,7 @@ int __init early_microcode_init(void)
 
     if ( microcode_ops )
     {
-        microcode_ops->collect_cpu_info(cpu, sig);
+        microcode_ops->collect_cpu_info(&this_cpu(cpu_sig));
 
         if ( ucode_mod.mod_end || ucode_blob.size )
             rc = early_microcode_update_cpu(true);
diff --git a/xen/arch/x86/microcode_amd.c b/xen/arch/x86/microcode_amd.c
index 3f42781..83ed8f9 100644
--- a/xen/arch/x86/microcode_amd.c
+++ b/xen/arch/x86/microcode_amd.c
@@ -78,23 +78,23 @@ struct mpbhdr {
 static DEFINE_SPINLOCK(microcode_update_lock);
 
 /* See comment in start_update() for cases when this routine fails */
-static int collect_cpu_info(unsigned int cpu, struct cpu_signature *csig)
+static int collect_cpu_info(struct cpu_signature *csig)
 {
-    struct cpuinfo_x86 *c = &cpu_data[cpu];
+    struct cpuinfo_x86 *c = &current_cpu_data;
 
     memset(csig, 0, sizeof(*csig));
 
     if ( (c->x86_vendor != X86_VENDOR_AMD) || (c->x86 < 0x10) )
     {
         printk(KERN_ERR "microcode: CPU%d not a capable AMD processor\n",
-               cpu);
+               smp_processor_id());
         return -EINVAL;
     }
 
     rdmsrl(MSR_AMD_PATCHLEVEL, csig->rev);
 
     pr_debug("microcode: CPU%d collect_cpu_info: patch_id=%#x\n",
-             cpu, csig->rev);
+             smp_processor_id(), csig->rev);
 
     return 0;
 }
@@ -153,17 +153,15 @@ static bool_t find_equiv_cpu_id(const struct 
equiv_cpu_entry *equiv_cpu_table,
 }
 
 static enum microcode_match_result microcode_fits(
-    const struct microcode_amd *mc_amd, unsigned int cpu)
+    const struct microcode_amd *mc_amd)
 {
+    unsigned int cpu = smp_processor_id();
     const struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
     const struct microcode_header_amd *mc_header = mc_amd->mpb;
     const struct equiv_cpu_entry *equiv_cpu_table = mc_amd->equiv_cpu_table;
     unsigned int current_cpu_id;
     unsigned int equiv_cpu_id;
 
-    /* We should bind the task to the CPU */
-    BUG_ON(cpu != raw_smp_processor_id());
-
     current_cpu_id = cpuid_eax(0x00000001);
 
     if ( !find_equiv_cpu_id(equiv_cpu_table, current_cpu_id, &equiv_cpu_id) )
@@ -192,9 +190,7 @@ static enum microcode_match_result microcode_fits(
 
 static bool match_cpu(const struct microcode_patch *patch)
 {
-    if ( !patch )
-        return false;
-    return microcode_fits(patch->mc_amd, smp_processor_id()) == NEW_UCODE;
+    return patch && (microcode_fits(patch->mc_amd) == NEW_UCODE);
 }
 
 static struct microcode_patch *alloc_microcode_patch(
@@ -251,18 +247,16 @@ static enum microcode_match_result compare_patch(
     return MIS_UCODE;
 }
 
-static int apply_microcode(unsigned int cpu)
+static int apply_microcode(void)
 {
     unsigned long flags;
     uint32_t rev;
     int hw_err;
+    unsigned int cpu = smp_processor_id();
     struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
     const struct microcode_header_amd *hdr;
     const struct microcode_patch *patch = microcode_get_cache();
 
-    /* We should bind the task to the CPU */
-    BUG_ON(raw_smp_processor_id() != cpu);
-
     if ( !match_cpu(patch) )
         return -EINVAL;
 
@@ -453,19 +447,16 @@ static bool_t check_final_patch_levels(unsigned int cpu)
     return 0;
 }
 
-static int cpu_request_microcode(unsigned int cpu, const void *buf,
-                                 size_t bufsize)
+static int cpu_request_microcode(const void *buf, size_t bufsize)
 {
     struct microcode_amd *mc_amd;
     size_t offset = 0;
     int error = 0;
     unsigned int current_cpu_id;
     unsigned int equiv_cpu_id;
+    unsigned int cpu = smp_processor_id();
     const struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
 
-    /* We should bind the task to the CPU */
-    BUG_ON(cpu != raw_smp_processor_id());
-
     current_cpu_id = cpuid_eax(0x00000001);
 
     if ( *(const uint32_t *)buf != UCODE_MAGIC )
@@ -564,14 +555,14 @@ static int cpu_request_microcode(unsigned int cpu, const 
void *buf,
         }
 
         /* Update cache if this patch covers current CPU */
-        if ( microcode_fits(new_patch->mc_amd, cpu) != MIS_UCODE )
+        if ( microcode_fits(new_patch->mc_amd) != MIS_UCODE )
             microcode_update_cache(new_patch);
         else
             microcode_free_patch(new_patch);
 
         if ( match_cpu(microcode_get_cache()) )
         {
-            error = apply_microcode(cpu);
+            error = apply_microcode();
             if ( error )
                 break;
         }
diff --git a/xen/arch/x86/microcode_intel.c b/xen/arch/x86/microcode_intel.c
index 9140eba..867e4f2 100644
--- a/xen/arch/x86/microcode_intel.c
+++ b/xen/arch/x86/microcode_intel.c
@@ -96,13 +96,12 @@ struct extended_sigtable {
 /* serialize access to the physical write to MSR 0x79 */
 static DEFINE_SPINLOCK(microcode_update_lock);
 
-static int collect_cpu_info(unsigned int cpu_num, struct cpu_signature *csig)
+static int collect_cpu_info(struct cpu_signature *csig)
 {
+    unsigned int cpu_num = smp_processor_id();
     struct cpuinfo_x86 *c = &cpu_data[cpu_num];
     uint64_t msr_content;
 
-    BUG_ON(cpu_num != smp_processor_id());
-
     memset(csig, 0, sizeof(*csig));
 
     if ( (c->x86_vendor != X86_VENDOR_INTEL) || (c->x86 < 6) )
@@ -285,9 +284,9 @@ static enum microcode_match_result compare_patch(
  * return 1 - found update
  * return < 0 - error
  */
-static int get_matching_microcode(const void *mc, unsigned int cpu)
+static int get_matching_microcode(const void *mc)
 {
-    struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
+    struct cpu_signature *sig = &this_cpu(cpu_sig);
     const struct microcode_header_intel *mc_header = mc;
     unsigned long total_size = get_totalsize(mc_header);
     void *new_mc = xmalloc_bytes(total_size);
@@ -314,24 +313,21 @@ static int get_matching_microcode(const void *mc, 
unsigned int cpu)
 
     pr_debug("microcode: CPU%d found a matching microcode update with"
              " version %#x (current=%#x)\n",
-             cpu, mc_header->rev, sig->rev);
+             smp_processord_id(), mc_header->rev, sig->rev);
 
     return 1;
 }
 
-static int apply_microcode(unsigned int cpu)
+static int apply_microcode(void)
 {
     unsigned long flags;
     uint64_t msr_content;
     unsigned int val[2];
     unsigned int cpu_num = raw_smp_processor_id();
-    struct cpu_signature *sig = &per_cpu(cpu_sig, cpu);
+    struct cpu_signature *sig = &this_cpu(cpu_sig);
     const struct microcode_intel *mc_intel;
     const struct microcode_patch *patch = microcode_get_cache();
 
-    /* We should bind the task to the CPU */
-    BUG_ON(cpu_num != cpu);
-
     if ( !match_cpu(patch) )
         return -EINVAL;
 
@@ -396,22 +392,18 @@ static long get_next_ucode_from_buffer(void **mc, const 
u8 *buf,
     return offset + total_size;
 }
 
-static int cpu_request_microcode(unsigned int cpu, const void *buf,
-                                 size_t size)
+static int cpu_request_microcode(const void *buf, size_t size)
 {
     long offset = 0;
     int error = 0;
     void *mc;
 
-    /* We should bind the task to the CPU */
-    BUG_ON(cpu != raw_smp_processor_id());
-
     while ( (offset = get_next_ucode_from_buffer(&mc, buf, size, offset)) > 0 )
     {
         error = microcode_sanity_check(mc);
         if ( error )
             break;
-        error = get_matching_microcode(mc, cpu);
+        error = get_matching_microcode(mc);
         if ( error < 0 )
             break;
         /*
@@ -429,7 +421,7 @@ static int cpu_request_microcode(unsigned int cpu, const 
void *buf,
         error = offset;
 
     if ( !error && match_cpu(microcode_get_cache()) )
-        error = apply_microcode(cpu);
+        error = apply_microcode();
 
     return error;
 }
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 65e9cee..c818cfc 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -364,7 +364,7 @@ void start_secondary(void *unused)
     if ( system_state <= SYS_STATE_smp_boot )
         early_microcode_update_cpu(false);
     else
-        microcode_resume_cpu(cpu);
+        microcode_resume_cpu();
 
     /*
      * If MSR_SPEC_CTRL is available, apply Xen's default setting and discard
diff --git a/xen/include/asm-x86/microcode.h b/xen/include/asm-x86/microcode.h
index 5b8289f..35223eb 100644
--- a/xen/include/asm-x86/microcode.h
+++ b/xen/include/asm-x86/microcode.h
@@ -20,10 +20,9 @@ struct microcode_patch {
 };
 
 struct microcode_ops {
-    int (*cpu_request_microcode)(unsigned int cpu, const void *buf,
-                                 size_t size);
-    int (*collect_cpu_info)(unsigned int cpu, struct cpu_signature *csig);
-    int (*apply_microcode)(unsigned int cpu);
+    int (*cpu_request_microcode)(const void *buf, size_t size);
+    int (*collect_cpu_info)(struct cpu_signature *csig);
+    int (*apply_microcode)(void);
     int (*start_update)(void);
     void (*free_patch)(void *mc);
     bool (*match_cpu)(const struct microcode_patch *patch);
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index 2862321..104faa9 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -568,7 +568,7 @@ int guest_wrmsr_xen(struct vcpu *v, uint32_t idx, uint64_t 
val);
 
 void microcode_set_module(unsigned int);
 int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void), unsigned long len);
-int microcode_resume_cpu(unsigned int cpu);
+int microcode_resume_cpu(void);
 int early_microcode_update_cpu(bool start_update);
 int early_microcode_init(void);
 int microcode_init_intel(void);
-- 
1.8.3.1


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