Omit RIP from the emulator's _regs array, which is used only for GPRs,
i.e. registers that can be referenced via ModRM and/or SIB bytes. The
emulator uses the dedicated _eip field for RIP, and manually reads from
_eip to handle RIP-relative addressing.
Replace all open coded instances of '16' with the new NR_EMULATOR_GPRS.
See also the comments above the read_gpr() and write_gpr() declarations,
and obviously the handling in writeback_registers().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 12 ++++++------
arch/x86/kvm/kvm_emulate.h | 10 +++++++++-
2 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c58366ae4da2..dd1bf116a9ed 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -247,8 +247,8 @@ enum x86_transfer_type {
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;
@@ -259,8 +259,8 @@ static ulong reg_read(struct x86_emulate_ctxt *ctxt, unsigned 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;
@@ -278,7 +278,7 @@ static void writeback_registers(struct x86_emulate_ctxt *ctxt)
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]);
}
@@ -2495,7 +2495,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt,
u16 selector;
int i, r;
- for (i = 0; i < 16; i++)
+ for (i = 0; i < NR_EMULATOR_GPRS; i++)
*reg_write(ctxt, i) = GET_SMSTATE(u64, smstate, 0x7ff8 - i * 8);
ctxt->_eip = GET_SMSTATE(u64, smstate, 0x7f78);
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index 8dff25d267b7..bdd4e9865ca9 100644
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -301,6 +301,14 @@ 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.
+ */
+#define NR_EMULATOR_GPRS (VCPU_REGS_R15 + 1)
+
struct x86_emulate_ctxt {
void *vcpu;
const struct x86_emulate_ops *ops;
@@ -363,7 +371,7 @@ struct x86_emulate_ctxt {
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;
--
2.36.1.124.g0e6072fb45-goog
