Detect VT-x

Makefile

@@ -8,13 +8,16 @@ CFLAGS += -ggdb
 # Add new source files (C or Assembler) here,
 # preferentially in alphabetical order.
 VISOR_SOURCES_x86_64 := \
+	src/vintel.c \
 	# end of x86_64 specific sources list
 
 # Architecture-agnostic kernel sources.
 # Add new source files (C or Assembler) here,
 # preferentially in alphabetical order.
-VISOR_SOURCES := \
-	efi.c \
+VISOR_SOURCES :=  \
+	src/alloc.c   \
+	src/efi.c     \
+	src/strlcpy.c \
 	$(VISOR_SOURCES_$(ARCH)) \
 	# end of sources list
 
@@ -34,11 +37,7 @@ clean:
 	rm -f build/visor.so
 	rm -f $(VISOR_TARGET)
 
-build/%.o: %.[cS] | build
-	@printf "CC %s\n" $@
-	@"$(CC)" $(CFLAGS) -MMD -MP -c -o $@ $< $(CPPFLAGS)
-
-build/$(ARCH)/%.o: $(ARCH)/%.[cS] | build/$(ARCH)
+build/src/%.o: src/%.[cS] | build/src
 	@printf "CC %s\n" $@
 	@"$(CC)" $(CFLAGS) -MMD -MP -c -o $@ $< $(CPPFLAGS)
 
@@ -53,7 +52,7 @@ $(VISOR_TARGET): build/visor.so | build
 build:
 	mkdir -p $@
 
-build/$(ARCH):
+build/src:
 	mkdir -p $@
 
 config.mk: | config.default.mk

bochsrc

@@ -0,0 +1,37 @@
+# configuration file generated by Bochs
+plugin_ctrl: unmapped=1, biosdev=1, speaker=1, extfpuirq=1, parallel=1, serial=1
+memory: host=64, guest=64
+romimage: file="/usr/share/OVMF/x64/MICROVM.fd", address=0x0, options=none
+vgaromimage: file="/usr/share/bochs/VGABIOS-lgpl-latest-cirrus"
+boot: floppy
+floppy_bootsig_check: disabled=0
+# no floppya
+# no floppyb
+ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
+ata0-master: type=none
+ata0-slave: type=none
+ata1: enabled=1, ioaddr1=0x170, ioaddr2=0x370, irq=15
+ata1-master: type=none
+ata1-slave: type=none
+pci: enabled=1, chipset=i440fx, slot1=cirrus
+vga: extension=cirrus, update_freq=5, realtime=1
+cpu: count=1, ips=4000000, model=bx_generic, reset_on_triple_fault=1, cpuid_limit_winnt=0, ignore_bad_msrs=1, mwait_is_nop=0
+cpuid: level=6, stepping=3, model=3, family=6, vendor_string="GenuineIntel", brand_string="              Intel(R) Pentium(R) 4 CPU        "
+cpuid: mmx=1, apic=xapic, simd=sse2, sse4a=0, misaligned_sse=0, sep=1, movbe=0, adx=0
+cpuid: aes=0, sha=0, xsave=0, xsaveopt=0, x86_64=1, 1g_pages=0, pcid=0, fsgsbase=0
+#cpuid: smep=0, smap=0, mwait=1, vmx=1
+print_timestamps: enabled=0
+port_e9_hack: enabled=0
+private_colormap: enabled=0
+clock: sync=none, time0=local, rtc_sync=0
+# no cmosimage
+# no loader
+log: -
+logprefix: %t%e%d
+debug: action=ignore
+info: action=report
+error: action=report
+panic: action=ask
+keyboard: type=mf, serial_delay=250, paste_delay=100000, user_shortcut=none
+mouse: type=ps2, enabled=0, toggle=ctrl+mbutton
+com1: enabled=1, mode=null

config.default.mk

@@ -10,6 +10,6 @@ LD = ld
 
 # Compilation flags
 CFLAGS   = -std=c17 -Wall -ffreestanding -fpic -nostdlib -fno-stack-protector -fno-stack-check -fshort-wchar -mno-red-zone -maccumulate-outgoing-args -mno-sse -mno-mmx -mno-80387
-CPPFLAGS = -Ignuefi/inc
+CPPFLAGS = -Ignuefi/inc -Iinclude
 LDFLAGS  = -shared -Bsymbolic -Lgnuefi -Tgnuefi/elf_$(ARCH)_efi.lds -nostdlib
 LIBS     = -lgnuefi -lefi

include/x86/cr.h

@@ -0,0 +1,30 @@
+#ifndef _VISOR_CR_H_
+#define _VISOR_CR_H_
+
+#include <stdint.h>
+
+static inline uint64_t
+readcr0(void)
+{
+	uint64_t v;
+	__asm__ ("mov %%cr0, %0\n\t" : "=a"(v));
+	return v;
+}
+
+static inline uint64_t
+readcr3(void)
+{
+	uint64_t v;
+	__asm__ ("mov %%cr3, %0\n\t" : "=a"(v));
+	return v;
+}
+
+static inline uint64_t
+readcr4(void)
+{
+	uint64_t v;
+	__asm__ ("mov %%cr4, %0\n\t" : "=a"(v));
+	return v;
+}
+
+#endif

include/x86/msr.h

@@ -0,0 +1,49 @@
+#ifndef _VISOR_MSR_H_
+#define _VISOR_MSR_H_
+
+#include <stdint.h>
+
+#define IA32_FEATURE_CONTROL    0x3A
+
+#define IA32_VMX_BASIC          0x480
+#define IA32_VMX_PINBASED_CTLS  0x481
+#define IA32_VMX_PROCBASED_CTLS 0x482
+#define IA32_VMX_EXIT_CTLS      0x483
+#define IA32_VMX_ENTRY_CTLS     0x484
+#define IA32_VMX_MISC           0x485
+#define IA32_VMX_CR0_FIXED0     0x486
+#define IA32_VMX_CR0_FIXED1     0x487
+#define IA32_VMX_CR4_FIXED0     0x488
+#define IA32_VMX_CR4_FIXED1     0x489
+#define IA32_VMX_VMCS_ENUM      0x48A
+
+static inline uint32_t
+rdmsr32(uint32_t msr)
+{
+	uint32_t value;
+	__asm__ ("rdmsr\n\t" : "=a"(value) : "c"(msr) : "d");
+	return value;
+}
+
+static inline uint64_t
+rdmsr64(uint32_t msr)
+{
+	uint64_t value;
+	__asm__ ("rdmsr\n\t" : "=A"(value) : "c"(msr));
+	return value;
+}
+
+static inline void
+wrmsr32(uint32_t msr, uint32_t value)
+{
+	uint32_t high = 0;
+	__asm__ ("wrmsr\n\t" :: "c"(msr), "a"(value), "d"(high));
+}
+
+static inline void
+wrmsr64(uint32_t msr, uint64_t value)
+{
+	__asm__ ("wrmsr\n\t" :: "c"(msr), "A"(value));
+}
+
+#endif

include/x86/vmx.h

@@ -0,0 +1,78 @@
+#ifndef _VISOR_VMX_H_
+#define _VISOR_VMX_H_
+
+#include <stdint.h>
+
+struct VMCS {
+	/* VMCS Header */
+	uint32_t revisionID;
+	uint32_t abortIndicator;
+	/* Guest-state area */
+	/* Host-state area */
+	/* VM-execution control fields */
+	/* VM-exit control fields */
+	/* VM-entry control fields */
+	/* VM-exit information fields */
+};
+
+static inline void
+vmxon(void *region)
+{
+	__asm__ volatile ("vmxon %0\n\t" :: "r"(region));
+}
+
+static inline void
+vmxoff(void)
+{
+	__asm__ volatile ("vmxoff\n\t" ::);
+}
+
+static inline void
+vmptrld(void *region)
+{
+	__asm__ volatile ("vmptrld %0\n\t" :: "r"(region));
+}
+
+static inline void
+vmptrst(void *arg)
+{
+	__asm__ volatile ("vmptrst\n\t" ::);
+}
+
+static inline void
+vmclear(void *region)
+{
+	__asm__ volatile ("vmclear %0\n\t" :: "r"(region));
+}
+
+static inline void
+vmlaunch(void)
+{
+	__asm__ volatile ("vmlaunch\n\t" ::);
+}
+
+static inline void
+vmresume(void)
+{
+	__asm__ volatile ("vmresume\n\t" ::);
+}
+
+static inline void
+vmread()
+{
+	__asm__ volatile ("vmread\n\t" ::);
+}
+
+static inline void
+vmwrite()
+{
+	__asm__ volatile ("vmwrite\n\t" ::);
+}
+
+static inline void
+vmcall()
+{
+	__asm__ volatile ("vmcall\n\t" ::);
+}
+
+#endif

src/alloc.c

@@ -0,0 +1,6 @@
+
+void *
+allocate_aligned()
+{
+	return (void *)0;
+}

src/efi.c

@@ -1,11 +1,26 @@
+#include <stdbool.h>
+
 #include <efi.h>
 #include <efilib.h>
 
+#include "virt.h"
+
+struct virt_vtable *virt = &virt_vtable_intel;
+
+static char virt_err[100];
+
 EFIAPI
 EFI_STATUS
 efi_main(EFI_HANDLE imageHandle, EFI_SYSTEM_TABLE *systemTable)
 {
 	InitializeLib(imageHandle, systemTable);
 	Print(L"Hello, World!\n");
+
+	if (!virt->has_support(virt_err, sizeof virt_err)) {
+		AsciiPrint(virt_err);
+	}
+
+	for (;;) {}
+
 	return EFI_SUCCESS;
 }

src/std.h

@@ -0,0 +1,8 @@
+#ifndef _VISOR_STD_H_
+#define _VISOR_STD_H_
+
+#include <stddef.h>
+
+size_t strlcpy(char *restrict dest, const char *restrict src, size_t size);
+
+#endif

src/strlcpy.c

@@ -0,0 +1,18 @@
+#include "std.h"
+
+size_t
+strlcpy(char *restrict dest, const char *restrict src, size_t size)
+{
+	size_t i = 0;
+	while (i + 1 < size && src[i]) {
+		dest[i] = src[i];
+		i++;
+	}
+	if (size) {
+		dest[i] = 0;
+	}
+	while (src[i]) {
+		i++;
+	}
+	return i;
+}

src/vintel.c

@@ -0,0 +1,53 @@
+#include <cpuid.h>
+#include <x86/msr.h>
+#include <x86/cr.h>
+
+#include "virt.h"
+#include "std.h"
+
+static bool
+vintel_has_bios_support(void)
+{
+	uint64_t value = rdmsr64(IA32_FEATURE_CONTROL);
+	return (value & 0x5) == 0x5;
+}
+
+static bool
+vintel_has_cpu_support(void)
+{
+	unsigned info[4];
+	__get_cpuid(0x1, &info[0], &info[1], &info[2], &info[3]);
+	return (info[2] & (1 << 5)) != 0;
+}
+
+static bool
+vintel_has_cr4_support(void)
+{
+	uint64_t value = readcr4();
+	return (value & (1 << 13)) != 0;
+}
+
+bool
+vintel_has_support(char *err, size_t errmax)
+{
+	if (!vintel_has_cpu_support()) {
+		strlcpy(err, "CPU does not support VT-x.", errmax);
+		return false;
+	}
+
+	if (!vintel_has_bios_support()) {
+		strlcpy(err, "VT-x support is not enabled in BIOS.", errmax);
+		return false;
+	}
+
+	if (!vintel_has_cr4_support()) {
+		strlcpy(err, "VT-x enable bit is not set in CR4.", errmax);
+		return false;
+	}
+
+	return true;
+}
+
+struct virt_vtable virt_vtable_intel = {
+	.has_support = vintel_has_support,
+};

src/virt.h

@@ -0,0 +1,15 @@
+#ifndef _VISOR_VIRT_H_
+#define _VISOR_VIRT_H_
+
+#include <stdbool.h>
+#include <stddef.h>
+
+struct virt_vtable {
+	bool (*has_support)(char *err, size_t errmax);
+};
+
+extern struct virt_vtable virt_vtable_intel;
+
+extern struct virt_vtable *virt;
+
+#endif