Kernel: Move hypervisor vendor ID string to ProcessorInfo

This will make it possible to expose it in /proc/cpuinfo. :^)

3 files changed, 31 insertions, 21 deletions

diff --git a/Kernel/Arch/x86/ProcessorInfo.h b/Kernel/Arch/x86/ProcessorInfo.h
index e2d4473312..44ac12244d 100644
--- a/Kernel/Arch/x86/ProcessorInfo.h
+++ b/Kernel/Arch/x86/ProcessorInfo.h
@@ -21,6 +21,7 @@ public:
     ProcessorInfo(Processor const& processor);
 
     StringView vendor_id_string() const { return m_vendor_id_string->view(); }
+    StringView hypervisor_vendor_id_string() const { return m_hypervisor_vendor_id_string->view(); }
     StringView brand_string() const { return m_brand_string->view(); }
     StringView features_string() const { return m_features_string->view(); }
     u32 display_model() const { return m_display_model; }
@@ -33,10 +34,12 @@ public:
 
 private:
     static NonnullOwnPtr<KString> build_vendor_id_string();
+    static NonnullOwnPtr<KString> build_hypervisor_vendor_id_string(Processor const&);
     static NonnullOwnPtr<KString> build_brand_string();
     static NonnullOwnPtr<KString> build_features_string(Processor const&);
 
     NonnullOwnPtr<KString> m_vendor_id_string;
+    NonnullOwnPtr<KString> m_hypervisor_vendor_id_string;
     NonnullOwnPtr<KString> m_brand_string;
     NonnullOwnPtr<KString> m_features_string;
     u32 m_display_model { 0 };
diff --git a/Kernel/Arch/x86/common/Processor.cpp b/Kernel/Arch/x86/common/Processor.cpp
index 15c5be3e28..941e172eac 100644
--- a/Kernel/Arch/x86/common/Processor.cpp
+++ b/Kernel/Arch/x86/common/Processor.cpp
@@ -676,18 +676,10 @@ UNMAP_AFTER_INIT void Processor::initialize(u32 cpu)
 UNMAP_AFTER_INIT void Processor::detect_hypervisor()
 {
     CPUID hypervisor_leaf_range(0x40000000);
+    auto hypervisor_vendor_id_string = m_info->hypervisor_vendor_id_string();
+    dmesgln("CPU[{}]: CPUID hypervisor signature '{}' ({:#x} {:#x} {:#x}), max leaf {:#x}", current_id(), hypervisor_vendor_id_string, hypervisor_leaf_range.ebx(), hypervisor_leaf_range.ecx(), hypervisor_leaf_range.edx(), hypervisor_leaf_range.eax());
 
-    // Get signature of hypervisor.
-    alignas(sizeof(u32)) char hypervisor_signature_buffer[13];
-    *reinterpret_cast<u32*>(hypervisor_signature_buffer) = hypervisor_leaf_range.ebx();
-    *reinterpret_cast<u32*>(hypervisor_signature_buffer + 4) = hypervisor_leaf_range.ecx();
-    *reinterpret_cast<u32*>(hypervisor_signature_buffer + 8) = hypervisor_leaf_range.edx();
-    hypervisor_signature_buffer[12] = '\0';
-    StringView hypervisor_signature(hypervisor_signature_buffer);
-
-    dmesgln("CPU[{}]: CPUID hypervisor signature '{}' ({:#x} {:#x} {:#x}), max leaf {:#x}", current_id(), hypervisor_signature, hypervisor_leaf_range.ebx(), hypervisor_leaf_range.ecx(), hypervisor_leaf_range.edx(), hypervisor_leaf_range.eax());
-
-    if (hypervisor_signature == "Microsoft Hv"sv)
+    if (hypervisor_vendor_id_string == "Microsoft Hv"sv)
         detect_hypervisor_hyperv(hypervisor_leaf_range);
 }
 
diff --git a/Kernel/Arch/x86/common/ProcessorInfo.cpp b/Kernel/Arch/x86/common/ProcessorInfo.cpp
index 5c6d0056a1..99e28bd49a 100644
--- a/Kernel/Arch/x86/common/ProcessorInfo.cpp
+++ b/Kernel/Arch/x86/common/ProcessorInfo.cpp
@@ -14,6 +14,7 @@ namespace Kernel {
 
 ProcessorInfo::ProcessorInfo(Processor const& processor)
     : m_vendor_id_string(build_vendor_id_string())
+    , m_hypervisor_vendor_id_string(build_hypervisor_vendor_id_string(processor))
     , m_brand_string(build_brand_string())
     , m_features_string(build_features_string(processor))
 {
@@ -35,21 +36,35 @@ ProcessorInfo::ProcessorInfo(Processor const& processor)
         m_display_model = model;
     }
 }
+static void emit_u32(StringBuilder& builder, u32 value)
+{
+    builder.appendff("{:c}{:c}{:c}{:c}",
+        value & 0xff,
+        (value >> 8) & 0xff,
+        (value >> 16) & 0xff,
+        (value >> 24) & 0xff);
+};
 
 NonnullOwnPtr<KString> ProcessorInfo::build_vendor_id_string()
 {
     CPUID cpuid(0);
     StringBuilder builder;
-    auto emit_u32 = [&](u32 value) {
-        builder.appendff("{:c}{:c}{:c}{:c}",
-            value & 0xff,
-            (value >> 8) & 0xff,
-            (value >> 16) & 0xff,
-            (value >> 24) & 0xff);
-    };
-    emit_u32(cpuid.ebx());
-    emit_u32(cpuid.edx());
-    emit_u32(cpuid.ecx());
+    emit_u32(builder, cpuid.ebx());
+    emit_u32(builder, cpuid.edx());
+    emit_u32(builder, cpuid.ecx());
+    return KString::must_create(builder.string_view());
+}
+
+NonnullOwnPtr<KString> ProcessorInfo::build_hypervisor_vendor_id_string(Processor const& processor)
+{
+    if (!processor.has_feature(CPUFeature::HYPERVISOR))
+        return KString::must_create({});
+
+    CPUID cpuid(0x40000000);
+    StringBuilder builder;
+    emit_u32(builder, cpuid.ebx());
+    emit_u32(builder, cpuid.ecx());
+    emit_u32(builder, cpuid.edx());
     return KString::must_create(builder.string_view());
 }