sys_regs.h

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2012,2013 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * Derived from arch/arm/kvm/coproc.h
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Authors: Christoffer Dall <c.dall@virtualopensystems.com>
 */
 
#ifndef __ARM64_KVM_SYS_REGS_LOCAL_H__
#define __ARM64_KVM_SYS_REGS_LOCAL_H__
 
#include <linux/bsearch.h>
 
#define reg_to_encoding(x)                      \
    sys_reg((u32)(x)->Op0, (u32)(x)->Op1,               \
        (u32)(x)->CRn, (u32)(x)->CRm, (u32)(x)->Op2)
 
struct sys_reg_params {
    u8  Op0;
    u8  Op1;
    u8  CRn;
    u8  CRm;
    u8  Op2;
    u64 regval;
    bool    is_write;
};
 
#define encoding_to_params(reg)                     \
    ((struct sys_reg_params){ .Op0 = sys_reg_Op0(reg),      \
                  .Op1 = sys_reg_Op1(reg),      \
                  .CRn = sys_reg_CRn(reg),      \
                  .CRm = sys_reg_CRm(reg),      \
                  .Op2 = sys_reg_Op2(reg) })
 
#define esr_sys64_to_params(esr)                                               \
    ((struct sys_reg_params){ .Op0 = ((esr) >> 20) & 3,                    \
                  .Op1 = ((esr) >> 14) & 0x7,                  \
                  .CRn = ((esr) >> 10) & 0xf,                  \
                  .CRm = ((esr) >> 1) & 0xf,                   \
                  .Op2 = ((esr) >> 17) & 0x7,                  \
                  .is_write = !((esr) & 1) })
 
#define esr_cp1x_32_to_params(esr)                      \
    ((struct sys_reg_params){ .Op1 = ((esr) >> 14) & 0x7,           \
                  .CRn = ((esr) >> 10) & 0xf,           \
                  .CRm = ((esr) >> 1) & 0xf,            \
                  .Op2 = ((esr) >> 17) & 0x7,           \
                  .is_write = !((esr) & 1) })
 
struct sys_reg_desc {
    /* Sysreg string for debug */
    const char *name;
 
    enum {
        AA32_DIRECT,
        AA32_LO,
        AA32_HI,
    } aarch32_map;
 
    /* MRS/MSR instruction which accesses it. */
    u8  Op0;
    u8  Op1;
    u8  CRn;
    u8  CRm;
    u8  Op2;
 
    /* Trapped access from guest, if non-NULL. */
    bool (*access)(struct kvm_vcpu *,
               struct sys_reg_params *,
               const struct sys_reg_desc *);
 
    /*
     * Initialization for vcpu. Return initialized value, or KVM
     * sanitized value for ID registers.
     */
    u64 (*reset)(struct kvm_vcpu *, const struct sys_reg_desc *);
 
    /* Index into sys_reg[], or 0 if we don't need to save it. */
    int reg;
 
    /* Value (usually reset value), or write mask for idregs */
    u64 val;
 
    /* Custom get/set_user functions, fallback to generic if NULL */
    int (*get_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
            u64 *val);
    int (*set_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
            u64 val);
 
    /* Return mask of REG_* runtime visibility overrides */
    unsigned int (*visibility)(const struct kvm_vcpu *vcpu,
                   const struct sys_reg_desc *rd);
};
 
#define REG_HIDDEN      (1 << 0) /* hidden from userspace and guest */
#define REG_HIDDEN_USER     (1 << 1) /* hidden from userspace only */
#define REG_RAZ         (1 << 2) /* RAZ from userspace and guest */
#define REG_USER_WI     (1 << 3) /* WI from userspace only */
 
static __printf(2, 3)
inline void print_sys_reg_msg(const struct sys_reg_params *p,
                       char *fmt, ...)
{
    va_list va;
 
    va_start(va, fmt);
    /* Look, we even formatted it for you to paste into the table! */
    kvm_pr_unimpl("%pV { Op0(%2u), Op1(%2u), CRn(%2u), CRm(%2u), Op2(%2u), func_%s },\n",
              &(struct va_format){ fmt, &va },
              p->Op0, p->Op1, p->CRn, p->CRm, p->Op2, p->is_write ? "write" : "read");
    va_end(va);
}
 
static inline void print_sys_reg_instr(const struct sys_reg_params *p)
{
    /* GCC warns on an empty format string */
    print_sys_reg_msg(p, "%s", "");
}
 
static inline bool ignore_write(struct kvm_vcpu *vcpu,
                const struct sys_reg_params *p)
{
    return true;
}
 
static inline bool read_zero(struct kvm_vcpu *vcpu,
                 struct sys_reg_params *p)
{
    p->regval = 0;
    return true;
}
 
/* Reset functions */
static inline u64 reset_unknown(struct kvm_vcpu *vcpu,
                 const struct sys_reg_desc *r)
{
    BUG_ON(!r->reg);
    BUG_ON(r->reg >= NR_SYS_REGS);
    __vcpu_sys_reg(vcpu, r->reg) = 0x1de7ec7edbadc0deULL;
    return __vcpu_sys_reg(vcpu, r->reg);
}
 
static inline u64 reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
    BUG_ON(!r->reg);
    BUG_ON(r->reg >= NR_SYS_REGS);
    __vcpu_sys_reg(vcpu, r->reg) = r->val;
    return __vcpu_sys_reg(vcpu, r->reg);
}
 
static inline unsigned int sysreg_visibility(const struct kvm_vcpu *vcpu,
                         const struct sys_reg_desc *r)
{
    if (likely(!r->visibility))
        return 0;
 
    return r->visibility(vcpu, r);
}
 
static inline bool sysreg_hidden(const struct kvm_vcpu *vcpu,
                 const struct sys_reg_desc *r)
{
    return sysreg_visibility(vcpu, r) & REG_HIDDEN;
}
 
static inline bool sysreg_hidden_user(const struct kvm_vcpu *vcpu,
                      const struct sys_reg_desc *r)
{
    if (likely(!r->visibility))
        return false;
 
    return r->visibility(vcpu, r) & (REG_HIDDEN | REG_HIDDEN_USER);
}
 
static inline bool sysreg_visible_as_raz(const struct kvm_vcpu *vcpu,
                     const struct sys_reg_desc *r)
{
    return sysreg_visibility(vcpu, r) & REG_RAZ;
}
 
static inline bool sysreg_user_write_ignore(const struct kvm_vcpu *vcpu,
                        const struct sys_reg_desc *r)
{
    return sysreg_visibility(vcpu, r) & REG_USER_WI;
}
 
static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
                  const struct sys_reg_desc *i2)
{
    BUG_ON(i1 == i2);
    if (!i1)
        return 1;
    else if (!i2)
        return -1;
    if (i1->Op0 != i2->Op0)
        return i1->Op0 - i2->Op0;
    if (i1->Op1 != i2->Op1)
        return i1->Op1 - i2->Op1;
    if (i1->CRn != i2->CRn)
        return i1->CRn - i2->CRn;
    if (i1->CRm != i2->CRm)
        return i1->CRm - i2->CRm;
    return i1->Op2 - i2->Op2;
}
 
static inline int match_sys_reg(const void *key, const void *elt)
{
    const unsigned long pval = (unsigned long)key;
    const struct sys_reg_desc *r = elt;
 
    return pval - reg_to_encoding(r);
}
 
static inline const struct sys_reg_desc *
find_reg(const struct sys_reg_params *params, const struct sys_reg_desc table[],
     unsigned int num)
{
    unsigned long pval = reg_to_encoding(params);
 
    return __inline_bsearch((void *)pval, table, num, sizeof(table[0]), match_sys_reg);
}
 
const struct sys_reg_desc *get_reg_by_id(u64 id,
                     const struct sys_reg_desc table[],
                     unsigned int num);
 
int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
             const struct sys_reg_desc table[], unsigned int num);
int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
             const struct sys_reg_desc table[], unsigned int num);
 
#define AA32(_x)    .aarch32_map = AA32_##_x
#define Op0(_x)     .Op0 = _x
#define Op1(_x)     .Op1 = _x
#define CRn(_x)     .CRn = _x
#define CRm(_x)     .CRm = _x
#define Op2(_x)     .Op2 = _x
 
#define SYS_DESC(reg)                   \
    .name = #reg,                   \
    Op0(sys_reg_Op0(reg)), Op1(sys_reg_Op1(reg)),   \
    CRn(sys_reg_CRn(reg)), CRm(sys_reg_CRm(reg)),   \
    Op2(sys_reg_Op2(reg))
 
#endif /* __ARM64_KVM_SYS_REGS_LOCAL_H__ */