feat(kernel): ✨ add kvm cpuid structures

CREDITS.md

@@ -27,6 +27,9 @@ License information can be found in the [LICENSES.md](LICENSES.md) file.
 ## CPUID 0x7
 - [CPUID](https://en.wikipedia.org/wiki/CPUID)
 
+## KVM CPUID
+- [kernel.org KVM CPUID](https://www.kernel.org/doc/html/v6.9/virt/kvm/x86/cpuid.html?highlight=cpuid)
+
 ## Network
 - [Beej's Guide to Network Programming](https://web.archive.org/web/20051210132103/http://users.pcnet.ro/dmoroian/beej/Beej.html)
 - [UDP Socket Programming](https://web.archive.org/web/20060229214053/http://www.cs.rutgers.edu/~pxk/417/notes/sockets/udp.html)

Kernel/include/cpu/x86/cpuid_kvm.hpp

@@ -0,0 +1,202 @@
+/*
+	This file is part of Fennix Kernel.
+
+	Fennix Kernel is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix Kernel is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <types.h>
+#include <debug.h>
+
+#if defined(__amd64__)
+typedef uint64_t cpuid_t;
+#elif defined(__i386__)
+typedef uint32_t cpuid_t;
+#else
+typedef uint64_t cpuid_t;
+#endif // __amd64__ || __i386__
+
+#if defined(__amd64__) || defined(__i386__)
+#define __kvm_cpuid_init(leaf)                            \
+	CPUID##leaf()                                         \
+	{                                                     \
+		asmv("cpuid" : "=a"(EAX.raw), "=b"(EBX.raw),      \
+			 "=c"(ECX.raw), "=d"(EDX.raw) : "a"(leaf));   \
+		if (!EAX.raw && !EBX.raw && !ECX.raw && !EDX.raw) \
+			warn("cpuid not supported");                  \
+	}
+
+#define __kvm_cpuid_init2(leaf, leaf2, suffix)                      \
+	CPUID##leaf##suffix()                                           \
+	{                                                               \
+		asmv("cpuid" : "=a"(EAX.raw), "=b"(EBX.raw),                \
+			 "=c"(ECX.raw), "=d"(EDX.raw) : "a"(leaf), "c"(leaf2)); \
+		if (!EAX.raw && !EBX.raw && !ECX.raw && !EDX.raw)           \
+			warn("cpuid not supported");                            \
+	}
+#else
+#define __kvm_cpuid_init(leaf) \
+	CPUID##leaf()              \
+	{                          \
+	}
+
+#define __kvm_cpuid_init2(leaf, leaf2, suffix) \
+	CPUID##leaf##suffix()                      \
+	{                                          \
+	}
+#endif
+
+namespace CPU
+{
+	namespace x86
+	{
+		namespace KVM
+		{
+			/* KVM_CPUID_SIGNATURE */
+			struct CPUID0x40000000
+			{
+				__kvm_cpuid_init(0x40000000);
+
+				union
+				{
+					struct
+					{
+						uint32_t MaximumFunction : 32;
+					};
+					cpuid_t raw;
+				} EAX;
+
+				union
+				{
+					struct
+					{
+						char Vendor[4];
+					};
+					cpuid_t raw;
+				} EBX;
+
+				union
+				{
+					struct
+					{
+						char Vendor[4];
+					};
+					cpuid_t raw;
+				} ECX;
+
+				union
+				{
+					struct
+					{
+						char Vendor[4];
+					};
+					cpuid_t raw;
+				} EDX;
+			};
+
+			/* KVM_CPUID_FEATURES */
+			struct CPUID0x40000001
+			{
+				__kvm_cpuid_init(0x40000001);
+
+				union
+				{
+					struct
+					{
+						/** kvmclock available at msrs 0x11 and 0x12 */
+						uint32_t KVM_FEATURE_CLOCKSOURCE : 1;
+
+						/** not necessary to perform delays on PIO operations */
+						uint32_t KVM_FEATURE_NOP_IO_DELAY : 1;
+
+						/** deprecated */
+						uint32_t KVM_FEATURE_MMU_OP : 1;
+
+						/** kvmclock available at msrs 0x4b564d00 and 0x4b564d01 */
+						uint32_t KVM_FEATURE_CLOCKSOURCE2 : 1;
+
+						/** async pf can be enabled by writing to msr 0x4b564d02 */
+						uint32_t KVM_FEATURE_ASYNC_PF : 1;
+
+						/** steal time can be enabled by writing to msr 0x4b564d03 */
+						uint32_t KVM_FEATURE_STEAL_TIME : 1;
+
+						/** paravirtualized end of interrupt handler can be enabled by writing to msr 0x4b564d04 */
+						uint32_t KVM_FEATURE_PV_EOI : 1;
+
+						/** guest checks this feature bit before enabling paravirtualized spinlock support */
+						uint32_t KVM_FEATURE_PV_UNHAULT : 1;
+
+						uint32_t _reserved8 : 1;
+
+						/** guest checks this feature bit before enabling paravirtualized tlb flush */
+						uint32_t KVM_FEATURE_PV_TLB_FLUSH : 1;
+
+						/** paravirtualized async PF VM EXIT can be enabled by setting bit 2 when writing to msr 0x4b564d02 */
+						uint32_t KVM_FEATURE_ASYNC_PF_VMEXIT : 1;
+
+						/** guest checks this feature bit before enabling paravirtualized send IPIs */
+						uint32_t KVM_FEATURE_PV_SEND_IPI : 1;
+
+						/** host-side polling on HLT can be disabled by writing to msr 0x4b564d05 */
+						uint32_t KVM_FEATURE_PV_POLL_CONTROL : 1;
+
+						/** guest checks this feature bit before using paravirtualized sched yield */
+						uint32_t KVM_FEATURE_PV_SCHED_YIELD : 1;
+
+						uint32_t __reserved14_23 : 10;
+
+						/** host will warn if no guest-side per-cpu warps are expected in kvmclock */
+						uint32_t KVM_FEATURE_CLOCKSOURCE_STABLE_BIT : 1;
+
+						uint32_t __reserved25_31 : 7;
+					};
+					cpuid_t raw;
+				} EAX;
+
+				union
+				{
+					struct
+					{
+						uint32_t __reserved0_31;
+					};
+					cpuid_t raw;
+				} EBX;
+
+				union
+				{
+					struct
+					{
+						uint32_t __reserved0_31;
+					};
+					cpuid_t raw;
+				} ECX;
+
+				union
+				{
+					struct
+					{
+						/** guest checks this feature bit to determine that vCPUs are never preempted for an unlimited time allowing optimizations */
+						uint32_t KVM_HINTS_REALTIME : 1;
+					};
+					cpuid_t raw;
+				} EDX;
+			};
+		}
+	}
+}
+
+#undef __kvm_cpuid_init
+#undef __kvm_cpuid_init2