[xen master] x86/ucode: load microcode earlier on boot CPU

[patchbot@xxxxxxx]

commit dc380df12acfe53ccdcbeecaaee3510a3b0e374e
Author:     Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
AuthorDate: Mon Dec 19 14:45:33 2022 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Dec 20 19:33:04 2022 +0000

    x86/ucode: load microcode earlier on boot CPU
    
    Call early_microcode_init() straight after multiboot modules become
    accessible. Modify it to load the ucode directly from the blob bypassing
    populating microcode_cache because xmalloc is still not available at
    that point during Xen boot.
    
    Introduce early_microcode_init_cache() for populating microcode_cache.
    It needs to rescan the modules in order to find the new virtual address
    of the ucode blob because it changes during the boot process, e.g.
    from 0x00000000010802fc to 0xffff83204dac52fc.
    
    While at it, drop alternative_vcall() from early_microcode_init() since
    it's not useful in an __init fuction.
    
    Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/cpu/microcode/core.c    | 66 ++++++++++++++++++++++++++++++------
 xen/arch/x86/include/asm/microcode.h |  7 +++-
 xen/arch/x86/include/asm/setup.h     |  3 --
 xen/arch/x86/setup.c                 | 10 ++++--
 4 files changed, 68 insertions(+), 18 deletions(-)

diff --git a/xen/arch/x86/cpu/microcode/core.c 
b/xen/arch/x86/cpu/microcode/core.c
index 85c05e480d..d14754e222 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -27,6 +27,7 @@
 #include <xen/err.h>
 #include <xen/guest_access.h>
 #include <xen/init.h>
+#include <xen/multiboot.h>
 #include <xen/param.h>
 #include <xen/spinlock.h>
 #include <xen/stop_machine.h>
@@ -198,7 +199,8 @@ void __init microcode_scan_module(
         bootstrap_map(NULL);
     }
 }
-void __init microcode_grab_module(
+
+static void __init microcode_grab_module(
     unsigned long *module_map,
     const multiboot_info_t *mbi)
 {
@@ -732,10 +734,54 @@ int microcode_update_one(void)
     return microcode_update_cpu(NULL);
 }
 
+static int __init early_update_cache(const void *data, size_t len)
+{
+    int rc = 0;
+    struct microcode_patch *patch;
+
+    if ( !data )
+        return -ENOMEM;
+
+    patch = parse_blob(data, len);
+    if ( IS_ERR(patch) )
+    {
+        printk(XENLOG_WARNING "Parsing microcode blob error %ld\n",
+               PTR_ERR(patch));
+        return PTR_ERR(patch);
+    }
+
+    if ( !patch )
+        return -ENOENT;
+
+    spin_lock(&microcode_mutex);
+    rc = microcode_update_cache(patch);
+    spin_unlock(&microcode_mutex);
+    ASSERT(rc);
+
+    return rc;
+}
+
+int __init microcode_init_cache(unsigned long *module_map,
+                                const struct multiboot_info *mbi)
+{
+    int rc = 0;
+
+    if ( ucode_scan )
+        /* Need to rescan the modules because they might have been relocated */
+        microcode_scan_module(module_map, mbi);
+
+    if ( ucode_mod.mod_end )
+        rc = early_update_cache(bootstrap_map(&ucode_mod),
+                                ucode_mod.mod_end);
+    else if ( ucode_blob.size )
+        rc = early_update_cache(ucode_blob.data, ucode_blob.size);
+
+    return rc;
+}
+
 /* BSP calls this function to parse ucode blob and then apply an update. */
 static int __init early_microcode_update_cpu(void)
 {
-    int rc = 0;
     const void *data = NULL;
     size_t len;
     struct microcode_patch *patch;
@@ -754,7 +800,7 @@ static int __init early_microcode_update_cpu(void)
     if ( !data )
         return -ENOMEM;
 
-    patch = parse_blob(data, len);
+    patch = ucode_ops.cpu_request_microcode(data, len, false);
     if ( IS_ERR(patch) )
     {
         printk(XENLOG_WARNING "Parsing microcode blob error %ld\n",
@@ -765,15 +811,11 @@ static int __init early_microcode_update_cpu(void)
     if ( !patch )
         return -ENOENT;
 
-    spin_lock(&microcode_mutex);
-    rc = microcode_update_cache(patch);
-    spin_unlock(&microcode_mutex);
-    ASSERT(rc);
-
-    return microcode_update_one();
+    return microcode_update_cpu(patch);
 }
 
-int __init early_microcode_init(void)
+int __init early_microcode_init(unsigned long *module_map,
+                                const struct multiboot_info *mbi)
 {
     const struct cpuinfo_x86 *c = &boot_cpu_data;
     int rc = 0;
@@ -797,7 +839,9 @@ int __init early_microcode_init(void)
         return -ENODEV;
     }
 
-    alternative_vcall(ucode_ops.collect_cpu_info);
+    microcode_grab_module(module_map, mbi);
+
+    ucode_ops.collect_cpu_info();
 
     if ( ucode_mod.mod_end || ucode_blob.size )
         rc = early_microcode_update_cpu();
diff --git a/xen/arch/x86/include/asm/microcode.h 
b/xen/arch/x86/include/asm/microcode.h
index 3b0234e9fa..62ce3418f7 100644
--- a/xen/arch/x86/include/asm/microcode.h
+++ b/xen/arch/x86/include/asm/microcode.h
@@ -6,6 +6,8 @@
 
 #include <public/xen.h>
 
+struct multiboot_info;
+
 struct cpu_signature {
     /* CPU signature (CPUID.1.EAX). */
     unsigned int sig;
@@ -21,7 +23,10 @@ DECLARE_PER_CPU(struct cpu_signature, cpu_sig);
 
 void microcode_set_module(unsigned int idx);
 int microcode_update(XEN_GUEST_HANDLE(const_void), unsigned long len);
-int early_microcode_init(void);
+int early_microcode_init(unsigned long *module_map,
+                         const struct multiboot_info *mbi);
+int microcode_init_cache(unsigned long *module_map,
+                         const struct multiboot_info *mbi);
 int microcode_update_one(void);
 
 #endif /* ASM_X86__MICROCODE_H */
diff --git a/xen/arch/x86/include/asm/setup.h b/xen/arch/x86/include/asm/setup.h
index ae470ea12f..ae0dd3915a 100644
--- a/xen/arch/x86/include/asm/setup.h
+++ b/xen/arch/x86/include/asm/setup.h
@@ -44,9 +44,6 @@ void *bootstrap_map(const module_t *mod);
 
 int xen_in_range(unsigned long mfn);
 
-void microcode_grab_module(
-    unsigned long *, const multiboot_info_t *);
-
 extern uint8_t kbd_shift_flags;
 
 #ifdef NDEBUG
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 4102aae76d..566422600d 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1173,6 +1173,12 @@ void __init noreturn __start_xen(unsigned long mbi_p)
         mod[i].reserved = 0;
     }
 
+    /*
+     * TODO: load ucode earlier once multiboot modules become accessible
+     * at an earlier stage.
+     */
+    early_microcode_init(module_map, mbi);
+
     if ( xen_phys_start )
     {
         relocated = true;
@@ -1755,11 +1761,9 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 
     init_IRQ();
 
-    microcode_grab_module(module_map, mbi);
-
     timer_init();
 
-    early_microcode_init();
+    microcode_init_cache(module_map, mbi); /* Needs xmalloc() */
 
     tsx_init(); /* Needs microcode.  May change HLE/RTM feature bits. */
 
--
generated by git-patchbot for /home/xen/git/xen.git#master