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Setting up a host TSS

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This commit is contained in:
Thomas Oltmann 2025-03-11 21:23:15 +01:00
parent e1ba08bbc0
commit af84732da1
4 changed files with 37 additions and 9 deletions
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19
include/x86/gdt.h
View file

@ -21,6 +21,25 @@ struct GDTR {
uint64_t base;
};
__attribute__ ((packed))
struct TSS {
uint32_t reserved0;
uint64_t rsp0;
uint64_t rsp1;
uint64_t rsp2;
uint64_t reserved1;
uint64_t ist1;
uint64_t ist2;
uint64_t ist3;
uint64_t ist4;
uint64_t ist5;
uint64_t ist6;
uint64_t ist7;
uint64_t reserved2;
uint16_t reserved3;
uint16_t iopb;
};
static inline struct GDTR
storegdt(void)
{

21
src/proc.c
View file

@ -3,18 +3,21 @@
#include "procvisor.h"
#include "bootstrap.h"
#define GDT_SIZE ( 3 * sizeof (struct segdescr))
#define GDT_SIZE ( 5 * sizeof (struct segdescr))
#define IDT_SIZE (256 * sizeof (struct intdescr))
#define TSS_SIZE (sizeof (struct TSS))
struct procvisor *procvisors[256];
static void
proc_fill_host_gdt(struct GDTR gdtr)
proc_fill_host_gdt(struct GDTR gdtr, struct TSS *tss)
{
struct segdescr *descrs = (void *)gdtr.base;
setsegdescr(&descrs[0], 0, 0, 0, 0); // null
setsegdescr(&descrs[1], 0, 0xffffff, 0x9B, 0xA0); // code
setsegdescr(&descrs[2], 0, 0xffffff, 0x93, 0xC0); // data
setsegdescr(&descrs[3], (uintptr_t)tss, TSS_SIZE - 1, 0x89, 0x00); // TSS
*(uint64_t *)(&descrs[4]) = (uintptr_t)tss >> 32;// TSS (continued)
}
static void
@ -37,22 +40,26 @@ proc_setup(void)
top -= sizeof (struct procvisor);
struct procvisor *pv = (void *)top;
// Carve out IDT
top -= IDT_SIZE;
pv->host_idtr.base = (uintptr_t)top;
pv->host_idtr.limit = IDT_SIZE - 1;
// Carve out GDT
top -= GDT_SIZE;
pv->host_gdtr.base = (uintptr_t)top;
pv->host_gdtr.limit = GDT_SIZE - 1;
// Carve out IDT
top -= IDT_SIZE;
pv->host_idtr.base = (uintptr_t)top;
pv->host_idtr.limit = IDT_SIZE - 1;
// Carve out TSS
top -= TSS_SIZE;
pv->host_tss = (void *)top;
// Leave the rest as stack
top -= ((uintptr_t)top & 0xf); // align on 16-byte boundary
pv->host_stack = top;
// Fill out GDT & IDT structures
proc_fill_host_gdt(pv->host_gdtr);
proc_fill_host_gdt(pv->host_gdtr, pv->host_tss);
proc_fill_host_idt(pv->host_idtr);
// Register procvisor & return

5
src/procvisor.h
View file

@ -7,9 +7,10 @@
/* Per-processor visor state and structures */
struct procvisor {
void *host_stack;
struct GDTR host_gdtr;
struct IDTR host_idtr;
struct GDTR host_gdtr;
struct TSS *host_tss;
void *host_stack;
//void *host_cr3;
//void *vmctl;
};

1
src/vintel.c
View file

@ -181,6 +181,7 @@ vintel_init_host(void)
vmwrite(HOST_DS_SELECTOR, 0x10);
vmwrite(HOST_FS_SELECTOR, 0x00);
vmwrite(HOST_GS_SELECTOR, 0x00);
vmwrite(HOST_TR_SELECTOR, 0x18);
// Set control registers
vmwrite(HOST_CR0, readcr0());