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Deshab-OS/CODE/UTSM/vmm/linux_loader.c
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2026-08-09 22:20:01 +08:00

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/* linux_loader.c — Linux 6.6 bzImage loader for UTSM VMX non-root guest.
*
* Responsibilities:
* 1. Find the bzImage among Limine boot modules
* 2. Parse the bzImage setup_header (Linux boot protocol)
* 3. Allocate host physical memory for guest regions
* 4. Load the protected-mode kernel into guest memory
* 5. Set up boot_params (e820, cmdline, initrd pointers)
* 6. Build guest page tables (identity-mapped 4GB, 2MB pages)
* 7. Build guest GDT (64-bit code/data/TSS)
* 8. EPT-map all guest regions (GPA → HPA)
*
* The actual VMCS configuration and vmlaunch happen in linux_boot.c.
*/
#include <utsm/linux_loader.h>
#include <utsm/vmx.h>
#include <utsm/ept.h>
#include <utsm/log.h>
#include <utsm/types.h>
#include <utsm/dma.h>
#include "../arch/x86_64/limine.h"
extern volatile struct limine_module_request g_module_request;
extern volatile struct limine_hhdm_request g_hhdm_request;
extern volatile struct limine_memmap_request g_memmap_request;
/* ===== Runtime helpers ===== */
static void mem_copy(void *dst, const void *src, u64 n) {
u8 *d = (u8 *)dst;
const u8 *s = (const u8 *)src;
for (u64 i = 0; i < n; i++) d[i] = s[i];
}
static void mem_zero(void *dst, u64 n) {
u8 *d = (u8 *)dst;
for (u64 i = 0; i < n; i++) d[i] = 0;
}
static u64 str_len(const char *s) {
u64 n = 0;
while (s[n]) n++;
return n;
}
/* ===== Guest state ===== */
static struct linux_guest_info g_guest;
static const char *g_default_cmdline = LINUX_DEFAULT_CMDLINE;
/* VSCode Phase 3: host virtual address of the graphics surface pool.
* The virtio-gpu 2D backend composites the scanout into this buffer; the
* desktop reads it to blit guest graphics onto the IDE host area. 0 = unused. */
static void *g_surface_vaddr = 0;
/* ===== Guest page table helpers =====
*
* Build identity-mapped 4-level page tables for the guest.
* Maps the first 4GB of GPA space using 2MB large pages.
*
* Layout (all at known GPAs for guest CR3):
* PML4 at g_guest.pgt_gpa + 0x0000 (1 page)
* PDPT at g_guest.pgt_gpa + 0x1000 (1 page)
* PD[0] at g_guest.pgt_gpa + 0x2000 (1 page, covers 0-1GB)
* PD[1] at g_guest.pgt_gpa + 0x3000 (1 page, covers 1-2GB)
* PD[2] at g_guest.pgt_gpa + 0x4000 (1 page, covers 2-3GB)
* PD[3] at g_guest.pgt_gpa + 0x5000 (1 page, covers 3-4GB)
*/
#define PGT_PML4_OFF 0x0000
#define PGT_PDPT_OFF 0x1000
#define PGT_PD_BASE 0x2000
#define PGT_PD_COUNT 4 /* 4 PD pages = 4GB */
#define PGT_TOTAL_PAGES (2 + PGT_PD_COUNT)
#define PGT_TOTAL_SIZE (PGT_TOTAL_PAGES * 4096)
/* x86-64 page table entry bits */
#define PTE_P (1ULL << 0) /* Present */
#define PTE_RW (1ULL << 1) /* Read/Write */
#define PTE_US (1ULL << 2) /* User/Supervisor */
#define PTE_PS (1ULL << 7) /* Page Size (large page) */
#define PTE_G (1ULL << 8) /* Global */
#define PTE_NX (1ULL << 63) /* No Execute */
static int build_guest_page_tables(u64 pgt_hpa) {
u64 *pml4 = (u64 *)(pgt_hpa + (g_hhdm_request.response ? g_hhdm_request.response->offset : 0));
u64 *pdpt = (u64 *)((u8 *)pml4 + 4096);
/* PML4[0] → PDPT */
u64 pdpt_gpa = g_guest.pgt_gpa + PGT_PDPT_OFF;
pml4[0] = pdpt_gpa | PTE_P | PTE_RW;
/* PDPT[0..3] → PD pages (each covers 1GB) */
for (int i = 0; i < PGT_PD_COUNT; i++) {
u64 pd_gpa = g_guest.pgt_gpa + PGT_PD_BASE + (u64)i * 4096;
pdpt[i] = pd_gpa | PTE_P | PTE_RW;
}
/* Each PD has 512 entries, each mapping a 2MB page (PS=1).
* PD[i] entry j maps GPA = i*1GB + j*2MB. */
for (int pd_idx = 0; pd_idx < PGT_PD_COUNT; pd_idx++) {
u64 *pd = (u64 *)((u8 *)pml4 + PGT_PD_BASE + (u64)pd_idx * 4096);
for (int j = 0; j < 512; j++) {
u64 page_gpa = (u64)pd_idx * (1ULL << 30) + (u64)j * (2ULL << 20);
pd[j] = page_gpa | PTE_P | PTE_RW | PTE_PS;
}
}
return 0;
}
/* ===== Guest GDT builder =====
*
* GDT layout (at g_guest.gdt_gpa):
* [0x00] null
* [0x08] 64-bit code: base=0, limit=0xFFFFF, L=1, G=1, present, DPL0, type=0x9B
* [0x10] 64-bit data: base=0, limit=0xFFFFF, G=1, present, DPL0, type=0x93
* [0x18] 64-bit TSS descriptor (16 bytes)
*
* TSS itself is placed in the same 4KB page after the GDT.
*/
typedef struct __attribute__((packed)) {
u16 limit_low;
u16 base_low;
u8 base_mid;
u8 access;
u8 flags_limit_high;
u8 base_high;
} gdt_entry64;
typedef struct __attribute__((packed)) {
u32 limit_low_base_low;
u8 base_mid;
u8 access;
u8 flags_limit_high;
u8 base_high;
u32 base_upper;
u32 reserved;
} tss_desc64;
static int build_guest_gdt(u64 gdt_hpa) {
u8 *gdt_page = (u8 *)(gdt_hpa + (g_hhdm_request.response ? g_hhdm_request.response->offset : 0));
mem_zero(gdt_page, 4096);
gdt_entry64 *gdt = (gdt_entry64 *)gdt_page;
/* [0x08] 64-bit code segment */
gdt[1].limit_low = 0xFFFF;
gdt[1].base_low = 0;
gdt[1].base_mid = 0;
gdt[1].access = 0x9B; /* present, DPL0, code, exec/read */
gdt[1].flags_limit_high = 0xAF; /* G=1, L=1 (64-bit), limit[19:16]=0xF */
gdt[1].base_high = 0;
/* [0x10] 64-bit data segment */
gdt[2].limit_low = 0xFFFF;
gdt[2].base_low = 0;
gdt[2].base_mid = 0;
gdt[2].access = 0x93; /* present, DPL0, data, read/write */
gdt[2].flags_limit_high = 0xCF; /* G=1, DB=1, limit[19:16]=0xF */
gdt[2].base_high = 0;
/* [0x18] 64-bit TSS descriptor (16 bytes).
* TSS structure lives at offset 0x100 in the same page (GPA = gdt_gpa + 0x100). */
tss_desc64 *tss_d = (tss_desc64 *)&gdt_page[0x18];
u64 tss_base = g_guest.gdt_gpa + 0x100;
u32 tss_limit = 0x67; /* 104-byte minimum 64-bit TSS */
tss_d->limit_low_base_low = (tss_limit & 0xFFFF) | ((u32)(tss_base & 0xFFFFFF) << 16);
tss_d->base_mid = (u8)((tss_base >> 24) & 0xFF);
tss_d->access = 0x89; /* present, DPL0, 64-bit TSS (available) */
tss_d->flags_limit_high = (u8)((tss_limit >> 16) & 0x0F);
tss_d->base_high = 0;
tss_d->base_upper = 0;
tss_d->reserved = 0;
return 0;
}
/* ===== e820 setup ===== */
struct __attribute__((packed)) e820_entry {
u64 addr;
u64 size;
u32 type;
};
static int setup_e820(void *bootparams_virt) {
u8 *bp = (u8 *)bootparams_virt;
/* e820_entries count at offset 0x1e8 */
u8 *e820_count = &bp[E820_ENTRIES_OFFSET];
struct e820_entry *table = (struct e820_entry *)&bp[E820_TABLE_OFFSET];
int n = 0;
/* Entry 0: 0x00000000-0x0009FFFF: usable RAM (640KB) */
table[n].addr = 0x00000000;
table[n].size = 0x000A0000;
table[n].type = E820_TYPE_RAM;
n++;
/* Entry 1: 0x000A0000-0x000FFFFF: reserved (VGA + BIOS) */
table[n].addr = 0x000A0000;
table[n].size = 0x00060000;
table[n].type = E820_TYPE_RESERVED;
n++;
/* Entry 2: 0x00100000-0x003FFFFF: reserved (UTSM area) */
table[n].addr = 0x00100000;
table[n].size = 0x00300000;
table[n].type = E820_TYPE_RESERVED;
n++;
/* Entry 3: 0x00400000-0x03FFFFFF: usable RAM (kernel + initrd + low RAM) */
table[n].addr = 0x00400000;
table[n].size = 0x03C00000; /* 60MB */
table[n].type = E820_TYPE_RAM;
n++;
/* Entry 4: 0x04000000-0x040FFFFF: reserved (IPC shared memory, 1MB) */
table[n].addr = 0x04000000;
table[n].size = 0x00100000; /* 1MB */
table[n].type = E820_TYPE_RESERVED;
n++;
/* Entry 5: 0x04100000-0x04FFFFFF: reserved (Graphics surface pool, 16MB)
* VSCode integration Phase 1: separate DMA region EPT-mapped into the
* guest; Linux user-space mmaps it via /dev/utsm as the scanout buffer. */
table[n].addr = LINUX_GUEST_SURFACE_GPA;
table[n].size = LINUX_GUEST_SURFACE_SIZE; /* 16MB */
table[n].type = E820_TYPE_RESERVED;
n++;
/* Entry 6: 0x05000000-0x5FFFFFFF: usable RAM (general RAM, ~1.4GB)
* VSCode integration Phase 1: expanded from 191MB to 1.4GB to fit
* VSCode + Electron + GUI stack (Xorg/modesetting + GTK + mesa). */
table[n].addr = LINUX_GUEST_RAM_GPA;
table[n].size = LINUX_GUEST_RAM_SIZE; /* 1.4GB */
table[n].type = E820_TYPE_RAM;
n++;
*e820_count = (u8)n;
return n;
}
/* ===== bzImage module finder ===== */
void *linux_find_bzimage_module(u64 *size_out) {
if (!g_module_request.response) {
log_error("[LINUX] no Limine module response");
return (void *)0;
}
struct limine_module_response *resp = g_module_request.response;
for (u64 i = 0; i < resp->module_count; i++) {
struct limine_file *file = resp->modules[i];
if (!file || !file->path) continue;
/* Look for paths containing "linux" or "bzImage" */
const char *p = file->path;
int match = 0;
/* Simple case-insensitive substring search for "linux" */
for (const char *s = p; *s; s++) {
if ((s[0] == 'l' || s[0] == 'L') &&
(s[1] == 'i' || s[1] == 'I') &&
(s[2] == 'n' || s[2] == 'N') &&
(s[3] == 'u' || s[3] == 'U') &&
(s[4] == 'x' || s[4] == 'X')) {
match = 1;
break;
}
}
if (!match) continue;
if (size_out) *size_out = file->size;
log_info("[LINUX] found bzImage module:");
log_info(file->path);
log_hex64("[LINUX] module size=", file->size);
return file->address;
}
log_warn("[LINUX] no bzImage module found");
return (void *)0;
}
/* ===== initrd module finder =====
*
* 在 Limine boot module 中查找 initramfs(路径含 "initrd" 或 "initramfs")。
* 返回模块数据指针,*size_out 为大小;未找到返回 NULL。 */
static void *linux_find_initrd_module(u64 *size_out) {
if (!g_module_request.response) return (void *)0;
struct limine_module_response *resp = g_module_request.response;
for (u64 i = 0; i < resp->module_count; i++) {
struct limine_file *file = resp->modules[i];
if (!file || !file->path) continue;
const char *p = file->path;
int match = 0;
for (const char *s = p; *s; s++) {
/* 匹配 "initrd"(如 linux-initrd.img) */
if ((s[0] == 'i' || s[0] == 'I') &&
(s[1] == 'n' || s[1] == 'N') &&
(s[2] == 'i' || s[2] == 'I') &&
(s[3] == 't' || s[3] == 'T') &&
(s[4] == 'r' || s[4] == 'R') &&
(s[5] == 'd' || s[5] == 'D')) {
match = 1;
break;
}
}
if (!match) continue;
if (size_out) *size_out = file->size;
log_info("[LINUX] found initrd module:");
log_info(file->path);
log_hex64("[LINUX] initrd size=", file->size);
return file->address;
}
log_warn("[LINUX] no initrd module found");
return (void *)0;
}
/* ===== rootfs module finder =====
*
* 在 Limine boot module 中查找 Arch rootfs 镜像(路径含 "rootfs")。
* 返回模块数据指针,*size_out 为大小;未找到返回 NULL。
* 该镜像通过 virtio-blk(memory-backed)暴露给 Linux guest 作为 /dev/vdb。 */
void *linux_find_rootfs_module(u64 *size_out) {
if (!g_module_request.response) return (void *)0;
struct limine_module_response *resp = g_module_request.response;
for (u64 i = 0; i < resp->module_count; i++) {
struct limine_file *file = resp->modules[i];
if (!file || !file->path) continue;
const char *p = file->path;
int match = 0;
for (const char *s = p; *s; s++) {
/* 匹配 "rootfs"(如 linux-rootfs.img) */
if ((s[0] == 'r' || s[0] == 'R') &&
(s[1] == 'o' || s[1] == 'O') &&
(s[2] == 'o' || s[2] == 'O') &&
(s[3] == 't' || s[3] == 'T') &&
(s[4] == 'f' || s[4] == 'F') &&
(s[5] == 's' || s[5] == 'S')) {
match = 1;
break;
}
}
if (!match) continue;
if (size_out) *size_out = file->size;
log_info("[LINUX] found rootfs module:");
log_info(file->path);
log_hex64("[LINUX] rootfs size=", file->size);
return file->address;
}
log_warn("[LINUX] no rootfs module found");
return (void *)0;
}
/* ===== extra rootfs module finder =====
*
* VSCode Phase 4:在 Limine boot module 中查找持久 rw 卷镜像
* (路径含 "extra",如 linux-extra-rootfs.img)。
* 通过 virtio-blk slot6(可写)暴露给 Linux guest 作为 /dev/vdc。 */
void *linux_find_extra_rootfs_module(u64 *size_out) {
if (!g_module_request.response) return (void *)0;
struct limine_module_response *resp = g_module_request.response;
for (u64 i = 0; i < resp->module_count; i++) {
struct limine_file *file = resp->modules[i];
if (!file || !file->path) continue;
const char *p = file->path;
int match = 0;
for (const char *s = p; *s; s++) {
/* 匹配 "extra"(如 linux-extra-rootfs.img) */
if ((s[0] == 'e' || s[0] == 'E') &&
(s[1] == 'x' || s[1] == 'X') &&
(s[2] == 't' || s[2] == 'T') &&
(s[3] == 'r' || s[3] == 'R') &&
(s[4] == 'a' || s[4] == 'A')) {
match = 1;
break;
}
}
if (!match) continue;
if (size_out) *size_out = file->size;
log_info("[LINUX] found extra-rootfs module:");
log_info(file->path);
log_hex64("[LINUX] extra-rootfs size=", file->size);
return file->address;
}
log_warn("[LINUX] no extra-rootfs module found");
return (void *)0;
}
/* ===== VSCode tarball module finder =====
*
* VSCode Phase 5:在 Limine boot module 中查找 VSCode tarball
* (路径含 "vscode",如 linux-vscode.tar.gz)。
* 由 lxc_vscode_install() 流式推入 guest 并解压到 /opt/vscode。
* 模块缺失属正常情况(未投放 tarball),返回 NULL 由调用方跳过。 */
void *linux_find_vscode_module(u64 *size_out) {
if (!g_module_request.response) return (void *)0;
struct limine_module_response *resp = g_module_request.response;
for (u64 i = 0; i < resp->module_count; i++) {
struct limine_file *file = resp->modules[i];
if (!file || !file->path) continue;
const char *p = file->path;
int match = 0;
for (const char *s = p; *s; s++) {
/* 匹配 "vscode"(如 linux-vscode.tar.gz) */
if ((s[0] == 'v' || s[0] == 'V') &&
(s[1] == 's' || s[1] == 'S') &&
(s[2] == 'c' || s[2] == 'C') &&
(s[3] == 'o' || s[3] == 'O') &&
(s[4] == 'd' || s[4] == 'D') &&
(s[5] == 'e' || s[5] == 'E')) {
match = 1;
break;
}
}
if (!match) continue;
if (size_out) *size_out = file->size;
log_info("[LINUX] found vscode tarball module:");
log_info(file->path);
log_hex64("[LINUX] vscode tarball size=", file->size);
return file->address;
}
log_info("[LINUX] no vscode tarball module (install skipped)");
return (void *)0;
}
/* ===== bzImage parser ===== */
int linux_parse_bzimage(const void *bzimage, u64 size,
u64 *payload_offset_out, u64 *payload_length_out,
u64 *init_size_out, u64 *entry_offset_out) {
const u8 *img = (const u8 *)bzimage;
if (size < 0x300) {
log_error("[LINUX] bzImage too small");
return -1;
}
/* Check boot_flag at 0x1fe */
u16 boot_flag = *(u16 *)&img[BZ_BOOT_FLAG_OFF];
if (boot_flag != 0xAA55) {
log_hex64("[LINUX] bad boot_flag=", boot_flag);
return -2;
}
/* Check header magic "HdrS" at 0x202 */
u32 magic = *(u32 *)&img[BZ_HEADER_OFF];
if (magic != BZ_HEADER_MAGIC) {
log_hex64("[LINUX] bad header magic=", magic);
return -3;
}
/* Check protocol version */
u16 version = *(u16 *)&img[BZ_VERSION_OFF];
log_hex64("[LINUX] boot protocol version=", version);
if (version < 0x020c) {
log_error("[LINUX] boot protocol too old");
return -4;
}
/* Check xloadflags for 64-bit kernel */
u16 xloadflags = *(u16 *)&img[BZ_XLOADFLAGS_OFF];
log_hex64("[LINUX] xloadflags=", xloadflags);
if (!(xloadflags & XLF_KERNEL_64)) {
log_error("[LINUX] not a 64-bit kernel");
return -5;
}
/* Payload offset and length */
u32 payload_offset = *(u32 *)&img[BZ_PAYLOAD_OFFSET_OFF];
u32 payload_length = *(u32 *)&img[BZ_PAYLOAD_LENGTH_OFF];
log_hex64("[LINUX] payload_offset=", payload_offset);
log_hex64("[LINUX] payload_length=", payload_length);
if (payload_offset + payload_length > size) {
log_error("[LINUX] payload exceeds image size");
return -6;
}
/* Init size (total memory needed for kernel init) */
u32 init_size = *(u32 *)&img[BZ_INIT_SIZE_ACTUAL_OFF];
if (init_size == 0) init_size = payload_length;
log_hex64("[LINUX] init_size=", init_size);
/* The 64-bit entry point is at offset 0x200 from the payload start.
* This is the "startup_64" symbol. */
u64 entry_offset = payload_offset + 0x200;
log_hex64("[LINUX] entry_offset=", entry_offset);
/* Setup sectors (for real-mode header size) */
u8 setup_sects = img[0x1f1];
if (setup_sects == 0) setup_sects = 4;
u64 setup_size = (setup_sects + 1) * 512;
log_hex64("[LINUX] setup_sects=", setup_sects);
log_hex64("[LINUX] setup_size=", setup_size);
if (payload_offset_out) *payload_offset_out = payload_offset;
if (payload_length_out) *payload_length_out = payload_length;
if (init_size_out) *init_size_out = init_size;
if (entry_offset_out) *entry_offset_out = entry_offset;
return 0;
}
/* ===== Boot params setup ===== */
static int setup_boot_params(void *bp_virt, u64 bp_gpa,
u64 kernel_entry_gpa,
u64 cmdline_gpa, u64 cmdline_len,
u64 initrd_gpa, u64 initrd_size,
const void *bzimage) {
(void)bp_gpa; /* GPA is used by EPT mapping, not needed here */
const u8 *img = (const u8 *)bzimage;
u8 *bp = (u8 *)bp_virt;
/* Zero entire boot_params */
mem_zero(bp, BOOT_PARAMS_SIZE);
/* Copy setup_header from bzImage (offset 0x1f1, length 0x1ef = 0x200 - 0x11) */
/* The setup_header in boot_params starts at 0x1f1 and goes to 0x2xx.
* We copy from bzImage offset 0x1f1 to boot_params offset 0x1f1. */
u64 hdr_copy_len = 0x210; /* copy a generous chunk */
if (hdr_copy_len > BOOT_PARAMS_SIZE - SETUP_HEADER_OFFSET) {
hdr_copy_len = BOOT_PARAMS_SIZE - SETUP_HEADER_OFFSET;
}
mem_copy(&bp[SETUP_HEADER_OFFSET], &img[SETUP_HEADER_OFFSET], hdr_copy_len);
/* Override key fields */
bp[BZ_TYPE_OF_LOADER_OFF] = 0xFF; /* custom bootloader */
/* loadflags: LOADED_HIGH | CAN_USE_HEAP */
u8 loadflags = bp[BZ_LOADFLAGS_OFF];
loadflags |= LOADFLAG_LOADED_HIGH | LOADFLAG_CAN_USE_HEAP;
bp[BZ_LOADFLAGS_OFF] = loadflags;
/* Command line pointer and size */
*(u32 *)&bp[BZ_CMD_LINE_PTR_OFF] = (u32)cmdline_gpa;
*(u32 *)&bp[BZ_CMDLINE_SIZE_OFF] = (u32)cmdline_len;
/* Initrd */
if (initrd_size > 0) {
*(u32 *)&bp[BZ_RAMDISK_IMAGE_OFF] = (u32)initrd_gpa;
*(u32 *)&bp[BZ_RAMDISK_SIZE_OFF] = (u32)initrd_size;
}
/* code32_start: set to kernel entry (informational) */
*(u32 *)&bp[BZ_CODE32_START_OFF] = (u32)kernel_entry_gpa;
/* Heap end pointer (offset 0x224): end of real-mode heap.
* Not critical for 64-bit boot, but set a reasonable value. */
*(u16 *)&bp[0x224] = 0xFE00; /* heap ends at 0xFE00 */
/* Set up e820 memory map */
int e820_count = setup_e820(bp_virt);
log_hex64("[LINUX] e820 entries=", (u64)e820_count);
return 0;
}
/* ===== Main loader entry ===== */
int linux_loader_init(void) {
log_info("[LINUX] loader init begin");
/* 1. Find bzImage module */
u64 bzimage_size = 0;
void *bzimage = linux_find_bzimage_module(&bzimage_size);
if (!bzimage) {
log_warn("[LINUX] no bzImage found, skipping Linux guest");
return -1;
}
/* 2. Parse bzImage header */
u64 payload_offset, payload_length, init_size, entry_offset;
if (linux_parse_bzimage(bzimage, bzimage_size,
&payload_offset, &payload_length,
&init_size, &entry_offset) != 0) {
log_error("[LINUX] bzImage parse failed");
return -2;
}
/* 3. Allocate host physical memory for guest regions */
/* Kernel: round up init_size to page boundary, align to 2MB */
u64 kernel_alloc_size = ((init_size + 0xFFFFF) & ~0xFFFFFULL);
if (kernel_alloc_size < payload_length) kernel_alloc_size = payload_length;
dkm_dma_buffer kernel_buf;
if (dma_alloc_pages(kernel_alloc_size / 4096, 2 * 1024 * 1024, 0, &kernel_buf) != 0) {
log_error("[LINUX] failed to alloc kernel memory");
return -3;
}
log_hex64("[LINUX] kernel HPA=", kernel_buf.phys);
log_hex64("[LINUX] kernel alloc size=", kernel_alloc_size);
/* Boot params: 1 page */
dkm_dma_buffer bp_buf;
if (dma_alloc_pages(1, 4096, 0, &bp_buf) != 0) {
log_error("[LINUX] failed to alloc boot_params");
return -4;
}
/* Page tables: PGT_TOTAL_PAGES pages */
dkm_dma_buffer pgt_buf;
if (dma_alloc_pages(PGT_TOTAL_PAGES, 4096, 0, &pgt_buf) != 0) {
log_error("[LINUX] failed to alloc page tables");
return -5;
}
/* GDT: 1 page */
dkm_dma_buffer gdt_buf;
if (dma_alloc_pages(1, 4096, 0, &gdt_buf) != 0) {
log_error("[LINUX] failed to alloc GDT");
return -6;
}
/* Stack: 1 page (stack grows down from top) */
dkm_dma_buffer stack_buf;
if (dma_alloc_pages(1, 4096, 0, &stack_buf) != 0) {
log_error("[LINUX] failed to alloc stack");
return -7;
}
/* Command line: 1 page */
dkm_dma_buffer cmdline_buf;
if (dma_alloc_pages(1, 4096, 0, &cmdline_buf) != 0) {
log_error("[LINUX] failed to alloc cmdline");
return -8;
}
/* General RAM: VSCode integration Phase 1 expansion.
* 1.4GB (LINUX_GUEST_RAM_SIZE) accommodates VSCode + Electron + GUI stack
* (Xorg/modesetting + GTK + mesa softpipe). Falls back to 1GB / 512MB if
* the host cannot allocate the full amount; 512MB is the floor for the
* Xfbdev + xterm MVP (Phase 3). Original allocation was 64MB. */
u64 ram_size = LINUX_GUEST_RAM_SIZE; /* 1.4GB */
dkm_dma_buffer ram_buf;
if (dma_alloc_pages(ram_size / 4096, 2 * 1024 * 1024, 0, &ram_buf) != 0) {
log_warn("[LINUX] failed to alloc guest RAM (1.4GB), trying 1GB");
ram_size = 1ULL * 1024 * 1024 * 1024; /* 1GB */
if (dma_alloc_pages(ram_size / 4096, 2 * 1024 * 1024, 0, &ram_buf) != 0) {
log_warn("[LINUX] failed to alloc guest RAM (1GB), trying 512MB");
ram_size = 512 * 1024 * 1024; /* 512MB floor for Phase 3 MVP */
if (dma_alloc_pages(ram_size / 4096, 2 * 1024 * 1024, 0, &ram_buf) != 0) {
log_error("[LINUX] failed to alloc guest RAM (512MB minimum)");
return -9;
}
}
}
log_hex64("[LINUX] guest RAM HPA=", ram_buf.phys);
log_hex64("[LINUX] guest RAM size=", ram_size);
/* 4. Load kernel image into allocated memory */
const u8 *kernel_src = (const u8 *)bzimage + payload_offset;
mem_copy(kernel_buf.virt, kernel_src, payload_length);
log_hex64("[LINUX] kernel loaded, size=", payload_length);
/* 5. Set up guest page tables */
g_guest.pgt_gpa = LINUX_GUEST_PGT_GPA;
build_guest_page_tables(pgt_buf.phys);
log_hex64("[LINUX] page tables built at HPA=", pgt_buf.phys);
/* 6. Set up guest GDT */
g_guest.gdt_gpa = LINUX_GUEST_GDT_GPA;
build_guest_gdt(gdt_buf.phys);
log_hex64("[LINUX] GDT built at HPA=", gdt_buf.phys);
/* 7. Set up command line */
u64 cmdline_len = str_len(g_default_cmdline) + 1; /* include NUL */
mem_copy(cmdline_buf.virt, g_default_cmdline, cmdline_len);
log_info("[LINUX] cmdline:");
log_info(g_default_cmdline);
/* 8. Set up boot_params */
g_guest.bootparams_gpa = LINUX_GUEST_BOOTPARAMS_GPA;
g_guest.kernel_gpa = LINUX_GUEST_KERNEL_GPA;
g_guest.kernel_entry = LINUX_GUEST_KERNEL_GPA + entry_offset;
g_guest.cmdline_gpa = LINUX_GUEST_CMDLINE_GPA;
g_guest.cmdline_size = cmdline_len;
/* 8.5. Load initrd (busybox initramfs) if present.
* initrd 放在 GPA 0x03000000(initrd 区,上限 16MB 到 IPC 区 0x04000000)。 */
g_guest.initrd_gpa = 0;
g_guest.initrd_size = 0;
{
u64 initrd_size = 0;
void *initrd = linux_find_initrd_module(&initrd_size);
if (initrd && initrd_size > 0) {
u64 initrd_max = LINUX_GUEST_IPC_SHM_GPA - LINUX_GUEST_INITRD_GPA; /* 16MB */
if (initrd_size > initrd_max) {
log_error("[LINUX] initrd too large (>16MB), skipped");
} else {
u64 initrd_pages = (initrd_size + 4095) / 4096;
dkm_dma_buffer initrd_buf;
if (dma_alloc_pages(initrd_pages, 4096, 0, &initrd_buf) != 0) {
log_error("[LINUX] failed to alloc initrd memory");
return -17;
}
mem_copy(initrd_buf.virt, initrd, initrd_size);
if (ept_map_range(LINUX_GUEST_INITRD_GPA, initrd_buf.phys,
initrd_pages * 4096, EPT_READ | EPT_WRITE) != 0) {
log_error("[LINUX] EPT map initrd failed");
return -18;
}
g_guest.initrd_gpa = LINUX_GUEST_INITRD_GPA;
g_guest.initrd_size = initrd_size;
log_hex64("[LINUX] initrd mapped GPA=", g_guest.initrd_gpa);
log_hex64("[LINUX] initrd size=", g_guest.initrd_size);
}
} else {
log_warn("[LINUX] booting without initrd (no userland!)");
}
}
setup_boot_params(bp_buf.virt, g_guest.bootparams_gpa,
g_guest.kernel_entry,
g_guest.cmdline_gpa, cmdline_len,
g_guest.initrd_gpa, g_guest.initrd_size,
bzimage);
log_hex64("[LINUX] boot_params at GPA=", g_guest.bootparams_gpa);
/* 9. EPT-map all guest regions (GPA → HPA) */
/* Kernel: GPA 0x01000000 → kernel HPA, RWX */
if (ept_map_range(g_guest.kernel_gpa, kernel_buf.phys,
kernel_alloc_size, EPT_RWX) != 0) {
log_error("[LINUX] EPT map kernel failed");
return -10;
}
/* Boot params: GPA 0x00400000 → bp HPA, RW */
if (ept_map_range(g_guest.bootparams_gpa, bp_buf.phys,
4096, EPT_READ | EPT_WRITE) != 0) {
log_error("[LINUX] EPT map boot_params failed");
return -11;
}
/* Page tables: GPA 0x00700000 → pgt HPA, RW */
if (ept_map_range(g_guest.pgt_gpa, pgt_buf.phys,
PGT_TOTAL_SIZE, EPT_READ | EPT_WRITE) != 0) {
log_error("[LINUX] EPT map page tables failed");
return -12;
}
/* GDT: GPA 0x00600000 → gdt HPA, RW */
if (ept_map_range(g_guest.gdt_gpa, gdt_buf.phys,
4096, EPT_READ | EPT_WRITE) != 0) {
log_error("[LINUX] EPT map GDT failed");
return -13;
}
/* Stack: GPA 0x00800000 → stack HPA, RW */
if (ept_map_range(LINUX_GUEST_STACK_GPA, stack_buf.phys,
4096, EPT_READ | EPT_WRITE) != 0) {
log_error("[LINUX] EPT map stack failed");
return -14;
}
/* Command line: GPA 0x00500000 → cmdline HPA, R */
if (ept_map_range(g_guest.cmdline_gpa, cmdline_buf.phys,
4096, EPT_READ) != 0) {
log_error("[LINUX] EPT map cmdline failed");
return -15;
}
/* General RAM: map the allocated RAM at GPA 0x05000000 (after surface pool).
* GPA layout (matches e820, VSCode integration Phase 1):
* 0x00400000-0x009FFFFF: fixed regions (boot_params, GDT, pgt, stack, cmdline)
* 0x01000000-0x02FFFFFF: kernel
* 0x03000000-0x03FFFFFF: initrd (if any)
* 0x04000000-0x040FFFFF: IPC shared memory (mapped by ipc_shm_init)
* 0x04100000-0x04FFFFFF: Graphics surface pool (mapped below)
* 0x05000000-0x5FFFFFFF: general RAM (~1.4GB, expanded Phase 1)
* Linux sees this as usable RAM in e820. */
u64 ram_gpa = LINUX_GUEST_RAM_GPA;
if (ept_map_range(ram_gpa, ram_buf.phys, ram_size, EPT_RWX) != 0) {
log_error("[LINUX] EPT map guest RAM failed");
return -16;
}
log_hex64("[LINUX] guest RAM mapped GPA=", ram_gpa);
/* VSCode integration Phase 1: allocate graphics surface pool and EPT-map
* it into the Linux guest at LINUX_GUEST_SURFACE_GPA. Linux user-space
* obtains a writable pointer to this region via UTSM_HCALL_SURFACE_INFO +
* /dev/utsm mmap; UTSM reads it to blit guest graphics to the Deshab
* framebuffer (Phase 3 virtio-gpu shadow scanout). Non-fatal on failure:
* Linux guest still runs, VSCode integration phases 2+ will degrade. */
{
dkm_dma_buffer surface_buf;
u64 surface_size = LINUX_GUEST_SURFACE_SIZE; /* 16MB */
if (dma_alloc_pages(surface_size / 4096, 2 * 1024 * 1024, 0, &surface_buf) != 0) {
log_warn("[LINUX] failed to alloc surface pool (16MB) — VSCode integration degraded");
g_guest.surface_hpa = 0;
g_guest.surface_gpa = 0;
g_guest.surface_size = 0;
} else if (ept_map_range(LINUX_GUEST_SURFACE_GPA, surface_buf.phys,
surface_size, EPT_READ | EPT_WRITE) != 0) {
log_warn("[LINUX] EPT map surface pool failed — VSCode integration degraded");
g_guest.surface_hpa = 0;
g_guest.surface_gpa = 0;
g_guest.surface_size = 0;
} else {
/* Zero the surface pool so guest reads deterministic data before
* the X server writes a real scanout. */
u8 *surface_virt = (u8 *)surface_buf.virt;
for (u64 i = 0; i < surface_size; i++) surface_virt[i] = 0;
g_guest.surface_hpa = surface_buf.phys;
g_guest.surface_gpa = LINUX_GUEST_SURFACE_GPA;
g_guest.surface_size = surface_size;
g_surface_vaddr = surface_buf.virt; /* VSCode Phase 3: for virtio-gpu + desktop blit */
log_hex64("[LINUX] surface pool HPA=", surface_buf.phys);
log_hex64("[LINUX] surface pool GPA=", g_guest.surface_gpa);
log_hex64("[LINUX] surface pool size=", surface_size);
}
}
/* Identity-map the first 1MB (BIOS area, needed by some Linux code paths) */
if (ept_identity_map(0, 0x100000, EPT_RWX) != 0) {
log_warn("[LINUX] EPT identity map first 1MB failed (non-critical)");
}
/* 10. Record guest info */
g_guest.kernel_size = payload_length;
g_guest.loaded = 1;
log_hex64("[LINUX] kernel GPA=", g_guest.kernel_gpa);
log_hex64("[LINUX] kernel entry=", g_guest.kernel_entry);
log_hex64("[LINUX] kernel size=", g_guest.kernel_size);
log_info("[LINUX] loader init ok");
return 0;
}
const struct linux_guest_info *linux_get_guest_info(void) {
return g_guest.loaded ? &g_guest : (struct linux_guest_info *)0;
}
/* VSCode integration Phase 1: query graphics surface pool.
* Returns 0 on success (surface pool allocated and mapped), -1 if not
* initialized. Caller may pass NULL for any output it doesn't need. */
int linux_get_surface_info(u64 *hpa_out, u64 *gpa_out, u64 *size_out) {
if (!g_guest.loaded || g_guest.surface_hpa == 0) {
return -1;
}
if (hpa_out) *hpa_out = g_guest.surface_hpa;
if (gpa_out) *gpa_out = g_guest.surface_gpa;
if (size_out) *size_out = g_guest.surface_size;
return 0;
}
/* VSCode Phase 3: return host virtual address of the surface pool.
* The virtio-gpu 2D backend composites the scanout here; the desktop reads it
* for blitting to the framebuffer. Returns NULL if the pool is not allocated. */
void *linux_get_surface_vaddr(void) {
return g_surface_vaddr;
}