acrn-hypervisor/hypervisor/include/arch/x86/gdt.h

285 lines
7.0 KiB
C

/*
* Copyright (C) 2018 Intel Corporation. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef GDT_H
#define GDT_H
/* GDT is defined in assembly so it can be used to switch modes before long mode
* is established.
* With 64-bit EFI this is not required since are already in long mode when EFI
* transfers control to the hypervisor. However, for any instantiation of the
* ACRN Hypervisor that requires a boot from reset the GDT will be
* used as mode transitions are being made to ultimately end up in long mode.
* For this reason we establish the GDT in assembly.
* This should not affect usage and convenience of interacting with the GDT in C
* as the complete definition of the GDT is driven by the defines in this file.
*
* Unless it proves to be not viable we will use a single GDT for all hypervisor
* CPUs, with space for per CPU LDT and TSS.
*/
/*
* Segment selectors in x86-64 and i386 are the same size, 8 bytes.
* Local Descriptor Table (LDT) selectors are 16 bytes on x86-64 instead of 8
* bytes.
* Task State Segment (TSS) selectors are 16 bytes on x86-64 instead of 8 bytes.
*/
#define X64_SEG_DESC_SIZE (0x8) /* In long mode SEG Descriptors are 8 bytes */
#define X64_LDT_DESC_SIZE (0x10)/* In long mode LDT Descriptors are 16 bytes */
#define X64_TSS_DESC_SIZE (0x10)/* In long mode TSS Descriptors are 16 bytes */
/*****************************************************************************
*
* BEGIN: Definition of the GDT.
*
* NOTE:
* If you change the size of the GDT or rearrange the location of descriptors
* within the GDT you must change both the defines and the C structure header.
*
*****************************************************************************/
/* Number of global 8 byte segments descriptor(s) */
#define HOST_GDT_RING0_SEG_SELECTORS (0x3) /* rsvd, code, data */
/* Offsets of global 8 byte segment descriptors */
#define HOST_GDT_RING0_RSVD_SEL (0x0000)
#define HOST_GDT_RING0_CODE_SEL (0x0008)
#define HOST_GDT_RING0_DATA_SEL (0x0010)
/* Number of global 16 byte LDT descriptor(s) */
#define HOST_GDT_RING0_TSS_SELECTORS (0x1)
/* One for each CPU in the hypervisor. */
/*****************************************************************************
*
* END: Definition of the GDT.
*
*****************************************************************************/
/* Offset to start of LDT Descriptors */
#define HOST_GDT_RING0_LDT_SEL \
(HOST_GDT_RING0_SEG_SELECTORS * X64_SEG_DESC_SIZE)
/* Offset to start of LDT Descriptors */
#define HOST_GDT_RING0_CPU_TSS_SEL (HOST_GDT_RING0_LDT_SEL)
/* Size of the GDT */
#define HOST_GDT_SIZE \
(HOST_GDT_RING0_CPU_TSS_SEL + \
(HOST_GDT_RING0_TSS_SELECTORS * X64_TSS_DESC_SIZE))
/* Defined position of Interrupt Stack Tables */
#define MACHINE_CHECK_IST (0x1)
#define DOUBLE_FAULT_IST (0x2)
#define STACK_FAULT_IST (0x3)
#ifndef ASSEMBLER
#include <types.h>
#include <cpu.h>
#define TSS_AVAIL (9)
/*
* Definition of an 8 byte code segment descriptor.
*/
union code_segment_descriptor {
uint64_t value;
struct {
union {
uint32_t value;
struct {
uint32_t limit_15_0:16;
uint32_t base_15_0:16;
} bits;
} low32;
union {
uint32_t value;
struct {
uint32_t base_23_16:8;
uint32_t accessed:1;
uint32_t readeable:1;
uint32_t conforming:1;
uint32_t bit11_set:1;
uint32_t bit12_set:1;
uint32_t dpl:2;
uint32_t present:1;
uint32_t limit_19_16:4;
uint32_t avl:1;
uint32_t x64flag:1;
uint32_t dflt:1;
uint32_t granularity:1;
uint32_t base_31_24:8;
} bits;
} high32;
} fields;
} __aligned(8);
/*
* Definition of an 8 byte data segment descriptor.
*/
union data_segment_descriptor {
uint64_t value;
struct {
union {
uint32_t value;
struct {
uint32_t limit_15_0:16;
uint32_t base_15_0:16;
} bits;
} low32;
union {
uint32_t value;
struct {
uint32_t base_23_16:8;
uint32_t accessed:1;
uint32_t writeable:1;
uint32_t expansion:1;
uint32_t bit11_clr:1;
uint32_t bit12_set:1;
uint32_t dpl:2;
uint32_t present:1;
uint32_t limit_19_16:4;
uint32_t avl:1;
uint32_t rsvd_clr:1;
uint32_t big:1;
uint32_t granularity:1;
uint32_t base_31_24:8;
} bits;
} high32;
} fields;
} __aligned(8);
/*
* Definition of an 8 byte system segment descriptor.
*/
union system_segment_descriptor {
uint64_t value;
struct {
union {
uint32_t value;
struct {
uint32_t limit_15_0:16;
uint32_t base_15_0:16;
} bits;
} low32;
union {
uint32_t value;
struct {
uint32_t base_23_16:8;
uint32_t type:4;
uint32_t bit12_clr:1;
uint32_t dpl:2;
uint32_t present:1;
uint32_t limit_19_16:4;
uint32_t rsvd_1:1;
uint32_t rsvd_2_clr:1;
uint32_t rsvd_3:1;
uint32_t granularity:1;
uint32_t base_31_24:8;
} bits;
} high32;
} fields;
} __aligned(8);
/*
* Definition of 16 byte TSS and LDT selectors.
*/
union tss_64_descriptor {
uint64_t value;
struct {
union {
uint32_t value;
struct {
uint32_t limit_15_0:16;
uint32_t base_15_0:16;
} bits;
} low32;
union {
uint32_t value;
struct {
uint32_t base_23_16:8;
uint32_t type:4;
uint32_t bit12_clr:1;
uint32_t dpl:2;
uint32_t present:1;
uint32_t limit_19_16:4;
uint32_t rsvd_1:1;
uint32_t rsvd_2_clr:1;
uint32_t rsvd_3:1;
uint32_t granularity:1;
uint32_t base_31_24:8;
} bits;
} high32;
uint32_t base_addr_63_32;
union {
uint32_t value;
struct {
uint32_t rsvd_7_0:8;
uint32_t bits_12_8_clr:4;
uint32_t rsvd_31_13:20;
} bits;
} offset_12;
} fields;
} __aligned(8);
/*****************************************************************************
*
* BEGIN: Definition of the GDT.
*
* NOTE:
* If you change the size of the GDT or rearrange the location of descriptors
* within the GDT you must change both the defines and the C structure header.
*
*****************************************************************************/
struct host_gdt {
uint64_t rsvd;
union code_segment_descriptor host_gdt_code_descriptor;
union data_segment_descriptor host_gdt_data_descriptor;
union tss_64_descriptor host_gdt_tss_descriptors;
} __aligned(8);
/*****************************************************************************
*
* END: Definition of the GDT.
*
*****************************************************************************/
/*
* x86-64 Task State Segment (TSS) definition.
*/
struct tss_64 {
uint32_t rsvd1;
uint64_t rsp0;
uint64_t rsp1;
uint64_t rsp2;
uint32_t rsvd2;
uint32_t rsvd3;
uint64_t ist1;
uint64_t ist2;
uint64_t ist3;
uint64_t ist4;
uint64_t ist5;
uint64_t ist6;
uint64_t ist7;
uint32_t rsvd4;
uint32_t rsvd5;
uint16_t rsvd6;
uint16_t io_map_base_addr;
} __packed __aligned(16);
/*
* Definition of the GDT descriptor.
*/
struct host_gdt_descriptor {
uint16_t len;
struct host_gdt *gdt;
} __packed;
extern struct host_gdt HOST_GDT;
extern struct host_gdt_descriptor HOST_GDTR;
void load_gdtr_and_tr(void);
#endif /* end #ifndef ASSEMBLER */
#endif /* GDT_H */