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Diffstat (limited to 'arch/x86/kernel/cpu/microcode/core.c')
-rw-r--r--arch/x86/kernel/cpu/microcode/core.c47
1 files changed, 33 insertions, 14 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index b3e94ef461fd..ce5f8a2e7ae6 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -44,7 +44,7 @@
static struct microcode_ops *microcode_ops;
-static bool dis_ucode_ldr;
+static bool dis_ucode_ldr = true;
static int __init disable_loader(char *str)
{
@@ -81,6 +81,7 @@ struct cpu_info_ctx {
static bool __init check_loader_disabled_bsp(void)
{
+ u32 a, b, c, d;
#ifdef CONFIG_X86_32
const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
const char *opt = "dis_ucode_ldr";
@@ -93,8 +94,20 @@ static bool __init check_loader_disabled_bsp(void)
bool *res = &dis_ucode_ldr;
#endif
- if (cmdline_find_option_bool(cmdline, option))
- *res = true;
+ a = 1;
+ c = 0;
+ native_cpuid(&a, &b, &c, &d);
+
+ /*
+ * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
+ * completely accurate as xen pv guests don't see that CPUID bit set but
+ * that's good enough as they don't land on the BSP path anyway.
+ */
+ if (c & BIT(31))
+ return *res;
+
+ if (cmdline_find_option_bool(cmdline, option) <= 0)
+ *res = false;
return *res;
}
@@ -122,9 +135,7 @@ void __init load_ucode_bsp(void)
{
int vendor;
unsigned int family;
-
- if (check_loader_disabled_bsp())
- return;
+ bool intel = true;
if (!have_cpuid_p())
return;
@@ -134,16 +145,27 @@ void __init load_ucode_bsp(void)
switch (vendor) {
case X86_VENDOR_INTEL:
- if (family >= 6)
- load_ucode_intel_bsp();
+ if (family < 6)
+ return;
break;
+
case X86_VENDOR_AMD:
- if (family >= 0x10)
- load_ucode_amd_bsp(family);
+ if (family < 0x10)
+ return;
+ intel = false;
break;
+
default:
- break;
+ return;
}
+
+ if (check_loader_disabled_bsp())
+ return;
+
+ if (intel)
+ load_ucode_intel_bsp();
+ else
+ load_ucode_amd_bsp(family);
}
static bool check_loader_disabled_ap(void)
@@ -162,9 +184,6 @@ void load_ucode_ap(void)
if (check_loader_disabled_ap())
return;
- if (!have_cpuid_p())
- return;
-
vendor = x86_vendor();
family = x86_family();