From 7477f99d05f845f7663467c6db3c333e56969f83 Mon Sep 17 00:00:00 2001
From: Benjamin Lamowski <benjamin.lamowski@genode-labs.com>
Date: Wed, 19 Oct 2022 16:25:55 +0200
Subject: [PATCH] base-hw: x86: detect CPU Vendor and SVM support

Ref #4826
---
 .../src/core/spec/x86_64/platform_support.cc  |  2 +-
 .../base-hw/src/include/hw/spec/x86_64/cpu.h  | 12 +++
 .../src/include/hw/spec/x86_64/x86_64.h       | 81 ++++++++++++++++++-
 3 files changed, 93 insertions(+), 2 deletions(-)

diff --git a/repos/base-hw/src/core/spec/x86_64/platform_support.cc b/repos/base-hw/src/core/spec/x86_64/platform_support.cc
index 0aba3437ca..7b3d97cece 100644
--- a/repos/base-hw/src/core/spec/x86_64/platform_support.cc
+++ b/repos/base-hw/src/core/spec/x86_64/platform_support.cc
@@ -54,7 +54,7 @@ void Platform::_init_additional_platform_info(Xml_generator &xml)
 	});
 	xml.node("hardware", [&] () {
 		xml.node("features", [&] () {
-			xml.attribute("svm", false);
+			xml.attribute("svm", Hw::Virtualization_support::has_svm());
 			xml.attribute("vmx", false);
 		});
 	});
diff --git a/repos/base-hw/src/include/hw/spec/x86_64/cpu.h b/repos/base-hw/src/include/hw/spec/x86_64/cpu.h
index 130adf1079..2063527fb4 100644
--- a/repos/base-hw/src/include/hw/spec/x86_64/cpu.h
+++ b/repos/base-hw/src/include/hw/spec/x86_64/cpu.h
@@ -104,10 +104,22 @@ struct Hw::X86_64_cpu
 		};
 	);
 
+	X86_64_MSR_REGISTER(Amd_vm_cr, 0xC0010114,
+		struct Svmdis : Bitfield< 4, 1> { }; /* SVM disabled */
+	);
+
+	X86_64_CPUID_REGISTER(Cpuid_0_ebx, 0, ebx);
+	X86_64_CPUID_REGISTER(Cpuid_0_ecx, 0, ecx);
+	X86_64_CPUID_REGISTER(Cpuid_0_edx, 0, edx);
+
 	X86_64_CPUID_REGISTER(Cpuid_1_edx, 1, edx,
 		struct Pat : Bitfield<16, 1> { };
 	);
 
+	X86_64_CPUID_REGISTER(Cpuid_80000001_ecx, 0x80000001, ecx,
+		struct Svm : Bitfield<2, 1> { };
+	);
+
 	Suspend_type suspend;
 };
 
diff --git a/repos/base-hw/src/include/hw/spec/x86_64/x86_64.h b/repos/base-hw/src/include/hw/spec/x86_64/x86_64.h
index 19f4a399e9..37468a7266 100644
--- a/repos/base-hw/src/include/hw/spec/x86_64/x86_64.h
+++ b/repos/base-hw/src/include/hw/spec/x86_64/x86_64.h
@@ -14,10 +14,15 @@
 #ifndef _SRC__LIB__HW__SPEC__X86_64__X86_64_H_
 #define _SRC__LIB__HW__SPEC__X86_64__X86_64_H_
 
+#include <base/log.h>
 #include <base/stdint.h>
 #include <hw/spec/x86_64/cpu.h>
 
-namespace Hw { struct Cpu_memory_map; }
+namespace Hw {
+	struct Cpu_memory_map;
+	struct Virtualization_support;
+	class Vendor;
+}
 
 
 struct Hw::Cpu_memory_map
@@ -35,4 +40,78 @@ struct Hw::Cpu_memory_map
 	}
 };
 
+struct Hw::Vendor
+{
+private:
+	static constexpr char const *const vendor_string[] = {
+		"GenuineIntel",
+		"AuthenticAMD",
+		"KVMKVMKVM",
+		"Microsoft Hv",
+		"VMwareVMware",
+		"XenVMMXenVMM"
+		"Unknown",
+	};
+
+public:
+	enum Vendor_id {
+		INTEL,
+		AMD,
+		KVM,
+		MICROSOFT,
+		VMWARE,
+		XEN,
+		UNKNOWN,
+	};
+
+	static Vendor_id get_vendor_id()
+	{
+		using Cpu = Hw::X86_64_cpu;
+		using Genode::uint32_t;
+
+		uint32_t ebx = static_cast<uint32_t>(Cpu::Cpuid_0_ebx::read());
+		uint32_t ecx = static_cast<uint32_t>(Cpu::Cpuid_0_ecx::read());
+		uint32_t edx = static_cast<uint32_t>(Cpu::Cpuid_0_edx::read());
+
+		Genode::size_t v;
+		for (v = 0; v <= Vendor_id::UNKNOWN; ++v)
+			if (*reinterpret_cast<uint32_t const *>(vendor_string[v] +
+			                                      0) == ebx &&
+			    *reinterpret_cast<uint32_t const *>(vendor_string[v] +
+			                                      4) == edx &&
+			    *reinterpret_cast<uint32_t const *>(vendor_string[v] +
+			                                      8) == ecx)
+				break;
+
+		return Vendor_id(v);
+	}
+};
+
+struct Hw::Virtualization_support
+{
+	using Cpu = Hw::X86_64_cpu;
+	static bool has_svm()
+	{
+		/*
+		 * Check for vendor because the CPUID bit checked for SVM is reserved
+		 * on Intel.
+		 */
+		if (Hw::Vendor::get_vendor_id() != Hw::Vendor::AMD)
+			return false;
+
+		Hw::X86_64_cpu::Cpuid_80000001_ecx::access_t cpuid_svm =
+				Hw::X86_64_cpu::Cpuid_80000001_ecx::read();
+
+		if (Hw::X86_64_cpu::Cpuid_80000001_ecx::Svm::get(cpuid_svm) != 0) {
+			Hw::X86_64_cpu::Amd_vm_cr::access_t amd_vm_cr =
+				Hw::X86_64_cpu::Amd_vm_cr::read();
+
+			if (Hw::X86_64_cpu::Amd_vm_cr::Svmdis::get(amd_vm_cr) == 0)
+				return true;
+		}
+
+		return false;
+	}
+};
+
 #endif /* _SRC__LIB__HW__SPEC__X86_64__X86_64_H_ */