I tried to write a tiny kernel like that. So, I rewrite code from the repository and changed the code for myself. When I tested the compiled kernel and clicked any key on keyboard, QEMU restarted many times until I close it. But when I compiled and runned the kernel from the repository, it worked fine.

main.asm (nasm)

bits 32
section .text
    ; GRUB multiboot
    align 4
    dd 0x1BADB002   ; magic number
    dd 0x00     ; flags
    dd - (0x1BADB002 + 0x00) ; checksum

global _start
global read_port
global write_port
global load_idt
global keyboard_handler

extern kmain
extern c_keyboard_handler

_start:
    cli
    mov esp, reserve
    call kmain
    hlt

read_port:
    mov edx, [esp+4]
    in al, dx
    ret

write_port:
    mov edx, [esp+4]
    mov al, [esp+4+4]
    out dx, al
    ret

load_idt:
    mov edx, [esp+4]
    lidt [edx]
    sti
    ret

keyboard_handler:
    call c_keyboard_handler
    iretd

section .bss
resb 8192
reserve:    ; reserve 8 Kbyte of memory for further usage

main.c

#include "main.h"
#include "keyboard.h"

char* vidmem = (char*)0xb8000;

void clear_screen()
{   
    unsigned int i = 0;
    while (i < 80 * 25 * 2) { // 80 * 25 * 2 means screen size
        vidmem[i] = ' ';
        vidmem[i+1] = 0x07;

        i += 2;
    }
}

void kprint(const char* text)
{   
    unsigned int i = 0;
    //unsigned int j = 0;
    while (text[i] != '') {
        vidmem[curloc++] = text[i];
        vidmem[curloc++] = 0x07;

        ++i;
    }

}

void kprint_newline(void)
{
    unsigned int line_size = 2 * 80;
    curloc = curloc + (line_size - curloc % (line_size));
}

void kmain(void)
{
    const char* hello_msg = "Booted Conquistador Hydrogenium";
    clear_screen();
    kprint(hello_msg);
    kprint_newline();
    
    idt_init(); 
    keyboard_init();

    while (1);
}

main.h

#ifndef MAIN_H_INCLUDED
#define MAIN_H_INCLUDED

//static char* vidmem = (char*)0xb0000;
static unsigned int curloc = 0; // current cursor location

#endif

keyboard.c

#include "keyboard.h"
#include "main.h"
#include "idt.h"
#include "keymap.h"

extern char read_port(unsigned short port);
extern void write_port(unsigned short port, unsigned char data);
extern void keyboard_handler();
extern void load_idt(unsigned long* idt_ptr);
extern unsigned char keymap[128];

char* vidptr = (char*)0xb0000;

struct IDT_entry IDT[256]; // 256 means interrupt vector for x86 architecture

void idt_init()
{   
    IDT[0x21].offset_lowerbits = (unsigned long) keyboard_handler & 0xffff; // keyboard address
    IDT[0x21].offset_higherbits = ( (unsigned long) keyboard_handler & 0xffff0000) >> 16;
    IDT[0x21].selector = 0x08; // kernel code segment offset
    IDT[0x21].zero = 0;
    IDT[0x21].type_attribute = 0x8e; // interrupt gate
            
    // ICW1 
    write_port(0x21, 0x11);
    write_port(0xA1, 0x11);

    // ICW2 - kind of links to first IRQs of PIC1 and PIC2
    write_port(0x21, 0x20);
    write_port(0xA1, 0x28);

    // ICW3 - cascading (not used yet => 0x00)
    write_port(0x21, 0x00);
    write_port(0xA1, 0x00);

    // ICW4 - inform processor about protected mode (x86)
    write_port(0x21, 0x01);
    write_port(0xA1, 0x01);
    write_port(0x21, 0xff); // mask interrupts
    write_port(0xA1, 0xff); // mask interrupts
                
    unsigned long idt_ptr[2];
    idt_ptr[0] = (sizeof (struct IDT_entry) * 256 /* IDT size) */) + ( ((unsigned long) IDT /* IDT address */ & 0xffff) << 16);
    idt_ptr[1] = (unsigned long) IDT /* IDT address*/ >> 16;

    load_idt(idt_ptr);
}

void keyboard_init()
{
    write_port(0x21, 0xFD); // 0xFD = 11111101, that is, only irq1 is enabled
}

void c_keyboard_handler()
{
    unsigned char status;
    char keycode;

    write_port(0x20, 0x20);

    status = read_port(0x64); // 0x64 is keyboard status port
    // lower bit of register is set, if buffer is not empty
    if (status & 0x01) {
        //unsigned int i = 0;
        keycode = read_port(0x60); // 0x60 is keyboard data port
        if (keycode > 0) {
            vidptr[curloc++] = keymap[(unsigned char) keycode];
            vidptr[curloc++] = 0x07;
        }
    }
}

keyboard.h

#ifndef KEYBOARD_H_INCLUDED
#define KEYBOARD_H_INCLUDED

void idt_init();
void keyboard_init();

#endif

idt.h

#ifndef IDT_H_INCLUDED
#define IDT_H_INCLUDED

struct IDT_entry {
    unsigned short int offset_lowerbits;
    unsigned short int offset_higherbits;   
    unsigned short int selector;
    unsigned char zero;
    unsigned char type_attr;
};

#endif

keymap.h

#ifndef KEYMAP_H_INCLUDED
#define KEYMAP_H_INCLUDED

unsigned char keymap[128] =
{
    0,  27, '1', '2', '3', '4', '5', '6', '7', '8', /* 9 */
  '9', '0', '-', '=', 'b', /* Backspace */
  't',         /* Tab */
  'q', 'w', 'e', 'r',   /* 19 */
  't', 'y', 'u', 'i', 'o', 'p', '[', ']', 'n', /* Enter key */
    0,          /* 29   - Control */
  'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', /* 39 */
 ''', '`',   0,        /* Left shift */
 '\', 'z', 'x', 'c', 'v', 'b', 'n',            /* 49 */
  'm', ',', '.', '/',   0,              /* Right shift */
  '*',
    0,  /* Alt */
  ' ',  /* Space bar */
    0,  /* Caps lock */
    0,  /* 59 - F1 key ... > */
    0,   0,   0,   0,   0,   0,   0,   0,
    0,  /* < ... F10 */
    0,  /* 69 - Num lock*/
    0,  /* Scroll Lock */
    0,  /* Home key */
    0,  /* Up Arrow */
    0,  /* Page Up */
  '-',
    0,  /* Left Arrow */
    0,
    0,  /* Right Arrow */
  '+',
    0,  /* 79 - End key*/
    0,  /* Down Arrow */
    0,  /* Page Down */
    0,  /* Insert Key */
    0,  /* Delete Key */
    0,   0,   0,
    0,  /* F11 Key */
    0,  /* F12 Key */
    0,  /* All other keys are undefined */
};

#endif

QEMU log

CPU Reset (CPU 0)
EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000000
ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000
EIP=00000000 EFL=00000000 [-------] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0000 00000000 00000000 00000000
CS =0000 00000000 00000000 00000000
SS =0000 00000000 00000000 00000000
DS =0000 00000000 00000000 00000000
FS =0000 00000000 00000000 00000000
GS =0000 00000000 00000000 00000000
LDT=0000 00000000 00000000 00000000
TR =0000 00000000 00000000 00000000
GDT=     00000000 00000000
IDT=     00000000 00000000
CR0=00000000 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=00000000 DR7=00000000
CCS=00000000 CCD=00000000 CCO=EFLAGS
EFER=0000000000000000
FCW=0000 FSW=0000 [ST=0] FTW=ff MXCSR=00000000
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
XMM00=0000000000000000 0000000000000000 XMM01=0000000000000000 0000000000000000
XMM02=0000000000000000 0000000000000000 XMM03=0000000000000000 0000000000000000
XMM04=0000000000000000 0000000000000000 XMM05=0000000000000000 0000000000000000
XMM06=0000000000000000 0000000000000000 XMM07=0000000000000000 0000000000000000
CPU Reset (CPU 0)
EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000663
ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000
EIP=0000fff0 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 0000ffff 00009300
CS =f000 ffff0000 0000ffff 00009b00
SS =0000 00000000 0000ffff 00009300
DS =0000 00000000 0000ffff 00009300
FS =0000 00000000 0000ffff 00009300
GS =0000 00000000 0000ffff 00009300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 0000ffff
IDT=     00000000 0000ffff
CR0=60000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000000 CCO=EFLAGS
EFER=0000000000000000
FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
XMM00=0000000000000000 0000000000000000 XMM01=0000000000000000 0000000000000000
XMM02=0000000000000000 0000000000000000 XMM03=0000000000000000 0000000000000000
XMM04=0000000000000000 0000000000000000 XMM05=0000000000000000 0000000000000000
XMM06=0000000000000000 0000000000000000 XMM07=0000000000000000 0000000000000000
Triple fault
CPU Reset (CPU 0)
EAX=001005fd EBX=00100564 ECX=00100564 EDX=00000021
ESI=00000000 EDI=00001000 EBP=00102578 ESP=00102560
EIP=00100175 EFL=00000206 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000cb2b4 00000027
IDT=     001025a0 00000800
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=00102550 CCO=EFLAGS
EFER=0000000000000000
FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
XMM00=0000000000000000 0000000000000000 XMM01=0000000000000000 0000000000000000
XMM02=0000000000000000 0000000000000000 XMM03=0000000000000000 0000000000000000
XMM04=0000000000000000 0000000000000000 XMM05=0000000000000000 0000000000000000
XMM06=0000000000000000 0000000000000000 XMM07=0000000000000000 0000000000000000
CPU Reset (CPU 0)
EAX=00000006 EBX=000f361e ECX=00000000 EDX=00000cf9
ESI=00000000 EDI=00100000 EBP=00000000 ESP=00000fc8
EIP=000ef348 EFL=00000046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f61e0 00000037
IDT=     000f621e 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000044 CCD=00009dd4 CCO=EFLAGS
EFER=0000000000000000
FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
XMM00=0000000000000000 0000000000000000 XMM01=0000000000000000 0000000000000000
XMM02=0000000000000000 0000000000000000 XMM03=0000000000000000 0000000000000000
XMM04=0000000000000000 0000000000000000 XMM05=0000000000000000 0000000000000000
XMM06=0000000000000000 0000000000000000 XMM07=0000000000000000 0000000000000000

I compiled and linked the kernel in elf_i386 format.

Host: Windows 10 (64 bit)
Written and compiled on: Arch Linux (64 bit) (VirtualBox)
Tested on: QEMU-system-i386

I hope for help of community.
Thanks.