static ulong reg_read(struct x86_emulate_ctxt *ctxt, unsigned nr)
{
- if (WARN_ON_ONCE(nr >= 16))
- nr &= 16 - 1;
+ if (WARN_ON_ONCE(nr >= NR_EMULATOR_GPRS))
+ nr &= NR_EMULATOR_GPRS - 1;
if (!(ctxt->regs_valid & (1 << nr))) {
ctxt->regs_valid |= 1 << nr;
static ulong *reg_write(struct x86_emulate_ctxt *ctxt, unsigned nr)
{
- if (WARN_ON_ONCE(nr >= 16))
- nr &= 16 - 1;
+ if (WARN_ON_ONCE(nr >= NR_EMULATOR_GPRS))
+ nr &= NR_EMULATOR_GPRS - 1;
ctxt->regs_valid |= 1 << nr;
ctxt->regs_dirty |= 1 << nr;
unsigned long dirty = ctxt->regs_dirty;
unsigned reg;
- for_each_set_bit(reg, &dirty, 16)
+ for_each_set_bit(reg, &dirty, NR_EMULATOR_GPRS)
ctxt->ops->write_gpr(ctxt, reg, ctxt->_regs[reg]);
}
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.
+ *
+ * TODO: this is technically wrong for 32-bit KVM, which only supports 8 GPRs;
+ * R8-R15 don't exist.
+ */
+#define NR_EMULATOR_GPRS 16
+
struct x86_emulate_ctxt {
void *vcpu;
const struct x86_emulate_ops *ops;
struct operand src2;
struct operand dst;
struct operand memop;
- unsigned long _regs[NR_VCPU_REGS];
+ unsigned long _regs[NR_EMULATOR_GPRS];
struct operand *memopp;
struct fetch_cache fetch;
struct read_cache io_read;