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linux/arch/x86/kvm/kvm_emulate.h
Sean Christopherson d99e4cb2ae KVM: x86: Use "is Intel compatible" helper to emulate SYSCALL in !64-bit 
Use guest_cpuid_is_intel_compatible() to determine whether SYSCALL in
32-bit Protected Mode (including Compatibility Mode) should #UD or succeed.
The existing code already does the exact equivalent of
guest_cpuid_is_intel_compatible(), just in a rather roundabout way.

No functional change intended.

Link: https://lore.kernel.org/r/20240405235603.1173076-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-06-10 14:29:38 -07:00

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/* SPDX-License-Identifier: GPL-2.0 */
/******************************************************************************
* x86_emulate.h
*
* Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
*
* Copyright (c) 2005 Keir Fraser
*
* From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
*/
#ifndef _ASM_X86_KVM_X86_EMULATE_H
#define _ASM_X86_KVM_X86_EMULATE_H
#include <asm/desc_defs.h>
#include "fpu.h"
struct x86_emulate_ctxt;
enum x86_intercept;
enum x86_intercept_stage;
struct x86_exception {
u8 vector;
bool error_code_valid;
u16 error_code;
bool nested_page_fault;
u64 address; /* cr2 or nested page fault gpa */
u8 async_page_fault;
unsigned long exit_qualification;
};
/*
* This struct is used to carry enough information from the instruction
* decoder to main KVM so that a decision can be made whether the
* instruction needs to be intercepted or not.
*/
struct x86_instruction_info {
u8 intercept; /* which intercept */
u8 rep_prefix; /* rep prefix? */
u8 modrm_mod; /* mod part of modrm */
u8 modrm_reg; /* index of register used */
u8 modrm_rm; /* rm part of modrm */
u64 src_val; /* value of source operand */
u64 dst_val; /* value of destination operand */
u8 src_bytes; /* size of source operand */
u8 dst_bytes; /* size of destination operand */
u8 ad_bytes; /* size of src/dst address */
u64 next_rip; /* rip following the instruction */
};
/*
* x86_emulate_ops:
*
* These operations represent the instruction emulator's interface to memory.
* There are two categories of operation: those that act on ordinary memory
* regions (*_std), and those that act on memory regions known to require
* special treatment or emulation (*_emulated).
*
* The emulator assumes that an instruction accesses only one 'emulated memory'
* location, that this location is the given linear faulting address (cr2), and
* that this is one of the instruction's data operands. Instruction fetches and
* stack operations are assumed never to access emulated memory. The emulator
* automatically deduces which operand of a string-move operation is accessing
* emulated memory, and assumes that the other operand accesses normal memory.
*
* NOTES:
* 1. The emulator isn't very smart about emulated vs. standard memory.
* 'Emulated memory' access addresses should be checked for sanity.
* 'Normal memory' accesses may fault, and the caller must arrange to
* detect and handle reentrancy into the emulator via recursive faults.
* Accesses may be unaligned and may cross page boundaries.
* 2. If the access fails (cannot emulate, or a standard access faults) then
* it is up to the memop to propagate the fault to the guest VM via
* some out-of-band mechanism, unknown to the emulator. The memop signals
* failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
* then immediately bail.
* 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
* cmpxchg8b_emulated need support 8-byte accesses.
* 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
*/
/* Access completed successfully: continue emulation as normal. */
#define X86EMUL_CONTINUE 0
/* Access is unhandleable: bail from emulation and return error to caller. */
#define X86EMUL_UNHANDLEABLE 1
/* Terminate emulation but return success to the caller. */
#define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
#define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */
#define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */
#define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */
#define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */
/* x86-specific emulation flags */
#define X86EMUL_F_WRITE BIT(0)
#define X86EMUL_F_FETCH BIT(1)
#define X86EMUL_F_IMPLICIT BIT(2)
#define X86EMUL_F_INVLPG BIT(3)
struct x86_emulate_ops {
void (*vm_bugged)(struct x86_emulate_ctxt *ctxt);
/*
* read_gpr: read a general purpose register (rax - r15)
*
* @reg: gpr number.
*/
ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
/*
* write_gpr: write a general purpose register (rax - r15)
*
* @reg: gpr number.
* @val: value to write.
*/
void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val);
/*
* read_std: Read bytes of standard (non-emulated/special) memory.
* Used for descriptor reading.
* @addr: [IN ] Linear address from which to read.
* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
* @bytes: [IN ] Number of bytes to read from memory.
* @system:[IN ] Whether the access is forced to be at CPL0.
*/
int (*read_std)(struct x86_emulate_ctxt *ctxt,
unsigned long addr, void *val,
unsigned int bytes,
struct x86_exception *fault, bool system);
/*
* write_std: Write bytes of standard (non-emulated/special) memory.
* Used for descriptor writing.
* @addr: [IN ] Linear address to which to write.
* @val: [OUT] Value write to memory, zero-extended to 'u_long'.
* @bytes: [IN ] Number of bytes to write to memory.
* @system:[IN ] Whether the access is forced to be at CPL0.
*/
int (*write_std)(struct x86_emulate_ctxt *ctxt,
unsigned long addr, void *val, unsigned int bytes,
struct x86_exception *fault, bool system);
/*
* fetch: Read bytes of standard (non-emulated/special) memory.
* Used for instruction fetch.
* @addr: [IN ] Linear address from which to read.
* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
* @bytes: [IN ] Number of bytes to read from memory.
*/
int (*fetch)(struct x86_emulate_ctxt *ctxt,
unsigned long addr, void *val, unsigned int bytes,
struct x86_exception *fault);
/*
* read_emulated: Read bytes from emulated/special memory area.
* @addr: [IN ] Linear address from which to read.
* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
* @bytes: [IN ] Number of bytes to read from memory.
*/
int (*read_emulated)(struct x86_emulate_ctxt *ctxt,
unsigned long addr, void *val, unsigned int bytes,
struct x86_exception *fault);
/*
* write_emulated: Write bytes to emulated/special memory area.
* @addr: [IN ] Linear address to which to write.
* @val: [IN ] Value to write to memory (low-order bytes used as
* required).
* @bytes: [IN ] Number of bytes to write to memory.
*/
int (*write_emulated)(struct x86_emulate_ctxt *ctxt,
unsigned long addr, const void *val,
unsigned int bytes,
struct x86_exception *fault);
/*
* cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
* emulated/special memory area.
* @addr: [IN ] Linear address to access.
* @old: [IN ] Value expected to be current at @addr.
* @new: [IN ] Value to write to @addr.
* @bytes: [IN ] Number of bytes to access using CMPXCHG.
*/
int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt,
unsigned long addr,
const void *old,
const void *new,
unsigned int bytes,
struct x86_exception *fault);
void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr);
int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt,
int size, unsigned short port, void *val,
unsigned int count);
int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt,
int size, unsigned short port, const void *val,
unsigned int count);
bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector,
struct desc_struct *desc, u32 *base3, int seg);
void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector,
struct desc_struct *desc, u32 base3, int seg);
unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt,
int seg);
void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
int (*cpl)(struct x86_emulate_ctxt *ctxt);
ulong (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr);
int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
int (*set_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
int (*get_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
int (*check_rdpmc_early)(struct x86_emulate_ctxt *ctxt, u32 pmc);
int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata);
void (*halt)(struct x86_emulate_ctxt *ctxt);
void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
int (*intercept)(struct x86_emulate_ctxt *ctxt,
struct x86_instruction_info *info,
enum x86_intercept_stage stage);
bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, u32 *eax, u32 *ebx,
u32 *ecx, u32 *edx, bool exact_only);
bool (*guest_has_movbe)(struct x86_emulate_ctxt *ctxt);
bool (*guest_has_fxsr)(struct x86_emulate_ctxt *ctxt);
bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt);
bool (*guest_cpuid_is_intel_compatible)(struct x86_emulate_ctxt *ctxt);
void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
bool (*is_smm)(struct x86_emulate_ctxt *ctxt);
bool (*is_guest_mode)(struct x86_emulate_ctxt *ctxt);
int (*leave_smm)(struct x86_emulate_ctxt *ctxt);
void (*triple_fault)(struct x86_emulate_ctxt *ctxt);
int (*set_xcr)(struct x86_emulate_ctxt *ctxt, u32 index, u64 xcr);
gva_t (*get_untagged_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr,
unsigned int flags);
};
/* Type, address-of, and value of an instruction's operand. */
struct operand {
enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
unsigned int bytes;
unsigned int count;
union {
unsigned long orig_val;
u64 orig_val64;
};
union {
unsigned long *reg;
struct segmented_address {
ulong ea;
unsigned seg;
} mem;
unsigned xmm;
unsigned mm;
} addr;
union {
unsigned long val;
u64 val64;
char valptr[sizeof(sse128_t)];
sse128_t vec_val;
u64 mm_val;
void *data;
};
};
struct fetch_cache {
u8 data[15];
u8 *ptr;
u8 *end;
};
struct read_cache {
u8 data[1024];
unsigned long pos;
unsigned long end;
};
/* Execution mode, passed to the emulator. */
enum x86emul_mode {
X86EMUL_MODE_REAL, /* Real mode. */
X86EMUL_MODE_VM86, /* Virtual 8086 mode. */
X86EMUL_MODE_PROT16, /* 16-bit protected mode. */
X86EMUL_MODE_PROT32, /* 32-bit protected mode. */
X86EMUL_MODE_PROT64, /* 64-bit (long) mode. */
};
/*
* fastop functions are declared as taking a never-defined fastop parameter,
* so they can't be called from C directly.
*/
struct fastop;
typedef void (*fastop_t)(struct fastop *);
/*
* The emulator's _regs array tracks only the GPRs, i.e. excludes RIP. RIP is
* tracked/accessed via _eip, and except for RIP relative addressing, which
* also uses _eip, RIP cannot be a register operand nor can it be an operand in
* a ModRM or SIB byte.
*/
#ifdef CONFIG_X86_64
#define NR_EMULATOR_GPRS 16
#else
#define NR_EMULATOR_GPRS 8
#endif
struct x86_emulate_ctxt {
void *vcpu;
const struct x86_emulate_ops *ops;
/* Register state before/after emulation. */
unsigned long eflags;
unsigned long eip; /* eip before instruction emulation */
/* Emulated execution mode, represented by an X86EMUL_MODE value. */
enum x86emul_mode mode;
/* interruptibility state, as a result of execution of STI or MOV SS */
int interruptibility;
bool perm_ok; /* do not check permissions if true */
bool tf; /* TF value before instruction (after for syscall/sysret) */
bool have_exception;
struct x86_exception exception;
/* GPA available */
bool gpa_available;
gpa_t gpa_val;
/*
* decode cache
*/
/* current opcode length in bytes */
u8 opcode_len;
u8 b;
u8 intercept;
u8 op_bytes;
u8 ad_bytes;
union {
int (*execute)(struct x86_emulate_ctxt *ctxt);
fastop_t fop;
};
int (*check_perm)(struct x86_emulate_ctxt *ctxt);
bool rip_relative;
u8 rex_prefix;
u8 lock_prefix;
u8 rep_prefix;
/* bitmaps of registers in _regs[] that can be read */
u16 regs_valid;
/* bitmaps of registers in _regs[] that have been written */
u16 regs_dirty;
/* modrm */
u8 modrm;
u8 modrm_mod;
u8 modrm_reg;
u8 modrm_rm;
u8 modrm_seg;
u8 seg_override;
u64 d;
unsigned long _eip;
/* Here begins the usercopy section. */
struct operand src;
struct operand src2;
struct operand dst;
struct operand memop;
unsigned long _regs[NR_EMULATOR_GPRS];
struct operand *memopp;
struct fetch_cache fetch;
struct read_cache io_read;
struct read_cache mem_read;
bool is_branch;
};
#define KVM_EMULATOR_BUG_ON(cond, ctxt) \
({ \
int __ret = (cond); \
\
if (WARN_ON_ONCE(__ret)) \
ctxt->ops->vm_bugged(ctxt); \
unlikely(__ret); \
})
/* Repeat String Operation Prefix */
#define REPE_PREFIX 0xf3
#define REPNE_PREFIX 0xf2
/* CPUID vendors */
#define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
#define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
#define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
#define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
#define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
#define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
#define X86EMUL_CPUID_VENDOR_HygonGenuine_ebx 0x6f677948
#define X86EMUL_CPUID_VENDOR_HygonGenuine_ecx 0x656e6975
#define X86EMUL_CPUID_VENDOR_HygonGenuine_edx 0x6e65476e
#define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
#define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
#define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
#define X86EMUL_CPUID_VENDOR_CentaurHauls_ebx 0x746e6543
#define X86EMUL_CPUID_VENDOR_CentaurHauls_ecx 0x736c7561
#define X86EMUL_CPUID_VENDOR_CentaurHauls_edx 0x48727561
static inline bool is_guest_vendor_intel(u32 ebx, u32 ecx, u32 edx)
{
return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx &&
ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx &&
edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx;
}
static inline bool is_guest_vendor_amd(u32 ebx, u32 ecx, u32 edx)
{
return (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx &&
ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx &&
edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx) ||
(ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx &&
ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx &&
edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx);
}
static inline bool is_guest_vendor_hygon(u32 ebx, u32 ecx, u32 edx)
{
return ebx == X86EMUL_CPUID_VENDOR_HygonGenuine_ebx &&
ecx == X86EMUL_CPUID_VENDOR_HygonGenuine_ecx &&
edx == X86EMUL_CPUID_VENDOR_HygonGenuine_edx;
}
enum x86_intercept_stage {
X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */
X86_ICPT_PRE_EXCEPT,
X86_ICPT_POST_EXCEPT,
X86_ICPT_POST_MEMACCESS,
};
enum x86_intercept {
x86_intercept_none,
x86_intercept_cr_read,
x86_intercept_cr_write,
x86_intercept_clts,
x86_intercept_lmsw,
x86_intercept_smsw,
x86_intercept_dr_read,
x86_intercept_dr_write,
x86_intercept_lidt,
x86_intercept_sidt,
x86_intercept_lgdt,
x86_intercept_sgdt,
x86_intercept_lldt,
x86_intercept_sldt,
x86_intercept_ltr,
x86_intercept_str,
x86_intercept_rdtsc,
x86_intercept_rdpmc,
x86_intercept_pushf,
x86_intercept_popf,
x86_intercept_cpuid,
x86_intercept_rsm,
x86_intercept_iret,
x86_intercept_intn,
x86_intercept_invd,
x86_intercept_pause,
x86_intercept_hlt,
x86_intercept_invlpg,
x86_intercept_invlpga,
x86_intercept_vmrun,
x86_intercept_vmload,
x86_intercept_vmsave,
x86_intercept_vmmcall,
x86_intercept_stgi,
x86_intercept_clgi,
x86_intercept_skinit,
x86_intercept_rdtscp,
x86_intercept_rdpid,
x86_intercept_icebp,
x86_intercept_wbinvd,
x86_intercept_monitor,
x86_intercept_mwait,
x86_intercept_rdmsr,
x86_intercept_wrmsr,
x86_intercept_in,
x86_intercept_ins,
x86_intercept_out,
x86_intercept_outs,
x86_intercept_xsetbv,
nr_x86_intercepts
};
/* Host execution mode. */
#if defined(CONFIG_X86_32)
#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
#elif defined(CONFIG_X86_64)
#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
#endif
int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int emulation_type);
bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
#define EMULATION_FAILED -1
#define EMULATION_OK 0
#define EMULATION_RESTART 1
#define EMULATION_INTERCEPTED 2
void init_decode_cache(struct x86_emulate_ctxt *ctxt);
int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
u16 tss_selector, int idt_index, int reason,
bool has_error_code, u32 error_code);
int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt);
static inline ulong reg_read(struct x86_emulate_ctxt *ctxt, unsigned nr)
{
if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt))
nr &= NR_EMULATOR_GPRS - 1;
if (!(ctxt->regs_valid & (1 << nr))) {
ctxt->regs_valid |= 1 << nr;
ctxt->_regs[nr] = ctxt->ops->read_gpr(ctxt, nr);
}
return ctxt->_regs[nr];
}
static inline ulong *reg_write(struct x86_emulate_ctxt *ctxt, unsigned nr)
{
if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt))
nr &= NR_EMULATOR_GPRS - 1;
BUILD_BUG_ON(sizeof(ctxt->regs_dirty) * BITS_PER_BYTE < NR_EMULATOR_GPRS);
BUILD_BUG_ON(sizeof(ctxt->regs_valid) * BITS_PER_BYTE < NR_EMULATOR_GPRS);
ctxt->regs_valid |= 1 << nr;
ctxt->regs_dirty |= 1 << nr;
return &ctxt->_regs[nr];
}
static inline ulong *reg_rmw(struct x86_emulate_ctxt *ctxt, unsigned nr)
{
reg_read(ctxt, nr);
return reg_write(ctxt, nr);
}
#endif /* _ASM_X86_KVM_X86_EMULATE_H */
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