137 lines
3.4 KiB
C
137 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Hyp portion of the (not much of an) Emulation layer for 32bit guests.
|
|
*
|
|
* Copyright (C) 2012,2013 - ARM Ltd
|
|
* Author: Marc Zyngier <marc.zyngier@arm.com>
|
|
*
|
|
* based on arch/arm/kvm/emulate.c
|
|
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
|
|
* Author: Christoffer Dall <c.dall@virtualopensystems.com>
|
|
*/
|
|
|
|
#include <linux/kvm_host.h>
|
|
#include <asm/kvm_emulate.h>
|
|
#include <asm/kvm_hyp.h>
|
|
|
|
/*
|
|
* stolen from arch/arm/kernel/opcodes.c
|
|
*
|
|
* condition code lookup table
|
|
* index into the table is test code: EQ, NE, ... LT, GT, AL, NV
|
|
*
|
|
* bit position in short is condition code: NZCV
|
|
*/
|
|
static const unsigned short cc_map[16] = {
|
|
0xF0F0, /* EQ == Z set */
|
|
0x0F0F, /* NE */
|
|
0xCCCC, /* CS == C set */
|
|
0x3333, /* CC */
|
|
0xFF00, /* MI == N set */
|
|
0x00FF, /* PL */
|
|
0xAAAA, /* VS == V set */
|
|
0x5555, /* VC */
|
|
0x0C0C, /* HI == C set && Z clear */
|
|
0xF3F3, /* LS == C clear || Z set */
|
|
0xAA55, /* GE == (N==V) */
|
|
0x55AA, /* LT == (N!=V) */
|
|
0x0A05, /* GT == (!Z && (N==V)) */
|
|
0xF5FA, /* LE == (Z || (N!=V)) */
|
|
0xFFFF, /* AL always */
|
|
0 /* NV */
|
|
};
|
|
|
|
/*
|
|
* Check if a trapped instruction should have been executed or not.
|
|
*/
|
|
bool __hyp_text kvm_condition_valid32(const struct kvm_vcpu *vcpu)
|
|
{
|
|
unsigned long cpsr;
|
|
u32 cpsr_cond;
|
|
int cond;
|
|
|
|
/* Top two bits non-zero? Unconditional. */
|
|
if (kvm_vcpu_get_hsr(vcpu) >> 30)
|
|
return true;
|
|
|
|
/* Is condition field valid? */
|
|
cond = kvm_vcpu_get_condition(vcpu);
|
|
if (cond == 0xE)
|
|
return true;
|
|
|
|
cpsr = *vcpu_cpsr(vcpu);
|
|
|
|
if (cond < 0) {
|
|
/* This can happen in Thumb mode: examine IT state. */
|
|
unsigned long it;
|
|
|
|
it = ((cpsr >> 8) & 0xFC) | ((cpsr >> 25) & 0x3);
|
|
|
|
/* it == 0 => unconditional. */
|
|
if (it == 0)
|
|
return true;
|
|
|
|
/* The cond for this insn works out as the top 4 bits. */
|
|
cond = (it >> 4);
|
|
}
|
|
|
|
cpsr_cond = cpsr >> 28;
|
|
|
|
if (!((cc_map[cond] >> cpsr_cond) & 1))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* adjust_itstate - adjust ITSTATE when emulating instructions in IT-block
|
|
* @vcpu: The VCPU pointer
|
|
*
|
|
* When exceptions occur while instructions are executed in Thumb IF-THEN
|
|
* blocks, the ITSTATE field of the CPSR is not advanced (updated), so we have
|
|
* to do this little bit of work manually. The fields map like this:
|
|
*
|
|
* IT[7:0] -> CPSR[26:25],CPSR[15:10]
|
|
*/
|
|
static void __hyp_text kvm_adjust_itstate(struct kvm_vcpu *vcpu)
|
|
{
|
|
unsigned long itbits, cond;
|
|
unsigned long cpsr = *vcpu_cpsr(vcpu);
|
|
bool is_arm = !(cpsr & PSR_AA32_T_BIT);
|
|
|
|
if (is_arm || !(cpsr & PSR_AA32_IT_MASK))
|
|
return;
|
|
|
|
cond = (cpsr & 0xe000) >> 13;
|
|
itbits = (cpsr & 0x1c00) >> (10 - 2);
|
|
itbits |= (cpsr & (0x3 << 25)) >> 25;
|
|
|
|
/* Perform ITAdvance (see page A2-52 in ARM DDI 0406C) */
|
|
if ((itbits & 0x7) == 0)
|
|
itbits = cond = 0;
|
|
else
|
|
itbits = (itbits << 1) & 0x1f;
|
|
|
|
cpsr &= ~PSR_AA32_IT_MASK;
|
|
cpsr |= cond << 13;
|
|
cpsr |= (itbits & 0x1c) << (10 - 2);
|
|
cpsr |= (itbits & 0x3) << 25;
|
|
*vcpu_cpsr(vcpu) = cpsr;
|
|
}
|
|
|
|
/**
|
|
* kvm_skip_instr - skip a trapped instruction and proceed to the next
|
|
* @vcpu: The vcpu pointer
|
|
*/
|
|
void __hyp_text kvm_skip_instr32(struct kvm_vcpu *vcpu, bool is_wide_instr)
|
|
{
|
|
bool is_thumb;
|
|
|
|
is_thumb = !!(*vcpu_cpsr(vcpu) & PSR_AA32_T_BIT);
|
|
if (is_thumb && !is_wide_instr)
|
|
*vcpu_pc(vcpu) += 2;
|
|
else
|
|
*vcpu_pc(vcpu) += 4;
|
|
kvm_adjust_itstate(vcpu);
|
|
}
|