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/* SPDX-License-Identifier: GPL-2.0-or-later */
/******************************************************************************
* util-xen.c
*
* Generic x86 (32-bit and 64-bit) instruction decoder and emulator hypervisor-
* only utility functions.
*/
#include "private.h"
#include <xen/nospec.h>
#include <xen/sched.h>
#include <asm/debugreg.h>
#include <asm/xstate.h>
#ifndef NDEBUG
void x86_emulate_free_state(struct x86_emulate_state *s)
{
check_state(s);
s->caller = NULL;
}
#endif
unsigned int x86_insn_opsize(const struct x86_emulate_state *s)
{
check_state(s);
return s->op_bytes << 3;
}
int x86_insn_modrm(const struct x86_emulate_state *s,
unsigned int *rm, unsigned int *reg)
{
check_state(s);
if ( unlikely(s->modrm_mod > 3) )
{
if ( rm )
*rm = ~0U;
if ( reg )
*reg = ~0U;
return -EINVAL;
}
if ( rm )
*rm = s->modrm_rm;
if ( reg )
*reg = s->modrm_reg;
return s->modrm_mod;
}
unsigned long x86_insn_operand_ea(const struct x86_emulate_state *s,
enum x86_segment *seg)
{
*seg = s->ea.type == OP_MEM ? s->ea.mem.seg : x86_seg_none;
check_state(s);
return s->ea.mem.off;
}
bool cf_check x86_insn_is_portio(const struct x86_emulate_state *s,
const struct x86_emulate_ctxt *ctxt)
{
switch ( ctxt->opcode )
{
case 0x6c ... 0x6f: /* INS / OUTS */
case 0xe4 ... 0xe7: /* IN / OUT imm8 */
case 0xec ... 0xef: /* IN / OUT %dx */
return true;
}
return false;
}
bool cf_check x86_insn_is_cr_access(const struct x86_emulate_state *s,
const struct x86_emulate_ctxt *ctxt)
{
switch ( ctxt->opcode )
{
unsigned int ext;
case X86EMUL_OPC(0x0f, 0x01):
if ( x86_insn_modrm(s, NULL, &ext) >= 0
&& (ext & 5) == 4 ) /* SMSW / LMSW */
return true;
break;
case X86EMUL_OPC(0x0f, 0x06): /* CLTS */
case X86EMUL_OPC(0x0f, 0x20): /* MOV from CRn */
case X86EMUL_OPC(0x0f, 0x22): /* MOV to CRn */
return true;
}
return false;
}
unsigned long x86_insn_immediate(const struct x86_emulate_state *s,
unsigned int nr)
{
check_state(s);
switch ( nr )
{
case 0:
return s->imm1;
case 1:
return s->imm2;
}
return 0;
}
int cf_check x86emul_read_xcr(unsigned int reg, uint64_t *val,
struct x86_emulate_ctxt *ctxt)
{
switch ( reg )
{
case 0:
*val = current->arch.xcr0;
return X86EMUL_OKAY;
case 1:
if ( current->domain->arch.cpuid->xstate.xgetbv1 )
break;
/* fall through */
default:
x86_emul_hw_exception(X86_EXC_GP, 0, ctxt);
return X86EMUL_EXCEPTION;
}
*val = xgetbv(reg);
return X86EMUL_OKAY;
}
/* Note: May be called with ctxt=NULL. */
int cf_check x86emul_write_xcr(unsigned int reg, uint64_t val,
struct x86_emulate_ctxt *ctxt)
{
switch ( reg )
{
case 0:
break;
default:
gp_fault:
if ( ctxt )
x86_emul_hw_exception(X86_EXC_GP, 0, ctxt);
return X86EMUL_EXCEPTION;
}
if ( unlikely(handle_xsetbv(reg, val) != 0) )
goto gp_fault;
return X86EMUL_OKAY;
}
#ifdef CONFIG_PV
/* Called with NULL ctxt in hypercall context. */
int cf_check x86emul_read_dr(unsigned int reg, unsigned long *val,
struct x86_emulate_ctxt *ctxt)
{
struct vcpu *curr = current;
/* HVM support requires a bit more plumbing before it will work. */
ASSERT(is_pv_vcpu(curr));
switch ( reg )
{
case 0 ... 3:
*val = array_access_nospec(curr->arch.dr, reg);
break;
case 4:
if ( curr->arch.pv.ctrlreg[4] & X86_CR4_DE )
goto ud_fault;
/* Fallthrough */
case 6:
*val = curr->arch.dr6;
break;
case 5:
if ( curr->arch.pv.ctrlreg[4] & X86_CR4_DE )
goto ud_fault;
/* Fallthrough */
case 7:
*val = curr->arch.dr7 | curr->arch.pv.dr7_emul;
break;
ud_fault:
default:
if ( ctxt )
x86_emul_hw_exception(X86_EXC_UD, X86_EVENT_NO_EC, ctxt);
return X86EMUL_EXCEPTION;
}
return X86EMUL_OKAY;
}
int cf_check x86emul_write_dr(unsigned int reg, unsigned long val,
struct x86_emulate_ctxt *ctxt)
{
struct vcpu *curr = current;
/* HVM support requires a bit more plumbing before it will work. */
ASSERT(is_pv_vcpu(curr));
switch ( set_debugreg(curr, reg, val) )
{
case 0:
return X86EMUL_OKAY;
case -ENODEV:
x86_emul_hw_exception(X86_EXC_UD, X86_EVENT_NO_EC, ctxt);
return X86EMUL_EXCEPTION;
default:
x86_emul_hw_exception(X86_EXC_GP, 0, ctxt);
return X86EMUL_EXCEPTION;
}
}
#endif /* CONFIG_PV */
int cf_check x86emul_cpuid(uint32_t leaf, uint32_t subleaf,
struct cpuid_leaf *res,
struct x86_emulate_ctxt *ctxt)
{
guest_cpuid(current, leaf, subleaf, res);
return X86EMUL_OKAY;
}
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