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-rw-r--r--arch/x86/lib/cache-smp.c9
-rw-r--r--arch/x86/lib/insn-eval.c151
-rw-r--r--arch/x86/lib/kaslr.c2
-rw-r--r--arch/x86/lib/msr.c5
4 files changed, 156 insertions, 11 deletions
diff --git a/arch/x86/lib/cache-smp.c b/arch/x86/lib/cache-smp.c
index c5c60d07308c..824664c0ecbd 100644
--- a/arch/x86/lib/cache-smp.c
+++ b/arch/x86/lib/cache-smp.c
@@ -2,6 +2,7 @@
#include <asm/paravirt.h>
#include <linux/smp.h>
#include <linux/export.h>
+#include <linux/kvm_types.h>
static void __wbinvd(void *dummy)
{
@@ -12,7 +13,7 @@ void wbinvd_on_cpu(int cpu)
{
smp_call_function_single(cpu, __wbinvd, NULL, 1);
}
-EXPORT_SYMBOL(wbinvd_on_cpu);
+EXPORT_SYMBOL_FOR_KVM(wbinvd_on_cpu);
void wbinvd_on_all_cpus(void)
{
@@ -24,7 +25,7 @@ void wbinvd_on_cpus_mask(struct cpumask *cpus)
{
on_each_cpu_mask(cpus, __wbinvd, NULL, 1);
}
-EXPORT_SYMBOL_GPL(wbinvd_on_cpus_mask);
+EXPORT_SYMBOL_FOR_KVM(wbinvd_on_cpus_mask);
static void __wbnoinvd(void *dummy)
{
@@ -35,10 +36,10 @@ void wbnoinvd_on_all_cpus(void)
{
on_each_cpu(__wbnoinvd, NULL, 1);
}
-EXPORT_SYMBOL_GPL(wbnoinvd_on_all_cpus);
+EXPORT_SYMBOL_FOR_KVM(wbnoinvd_on_all_cpus);
void wbnoinvd_on_cpus_mask(struct cpumask *cpus)
{
on_each_cpu_mask(cpus, __wbnoinvd, NULL, 1);
}
-EXPORT_SYMBOL_GPL(wbnoinvd_on_cpus_mask);
+EXPORT_SYMBOL_FOR_KVM(wbnoinvd_on_cpus_mask);
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 4e385cbfd444..e03eeec55cfe 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -63,11 +63,10 @@ static bool is_string_insn(struct insn *insn)
bool insn_has_rep_prefix(struct insn *insn)
{
insn_byte_t p;
- int i;
insn_get_prefixes(insn);
- for_each_insn_prefix(insn, i, p) {
+ for_each_insn_prefix(insn, p) {
if (p == 0xf2 || p == 0xf3)
return true;
}
@@ -92,13 +91,13 @@ bool insn_has_rep_prefix(struct insn *insn)
static int get_seg_reg_override_idx(struct insn *insn)
{
int idx = INAT_SEG_REG_DEFAULT;
- int num_overrides = 0, i;
+ int num_overrides = 0;
insn_byte_t p;
insn_get_prefixes(insn);
/* Look for any segment override prefixes. */
- for_each_insn_prefix(insn, i, p) {
+ for_each_insn_prefix(insn, p) {
insn_attr_t attr;
attr = inat_get_opcode_attribute(p);
@@ -1676,3 +1675,147 @@ enum insn_mmio_type insn_decode_mmio(struct insn *insn, int *bytes)
return type;
}
+
+/*
+ * Recognise typical NOP patterns for both 32bit and 64bit.
+ *
+ * Notably:
+ * - NOP, but not: REP NOP aka PAUSE
+ * - NOPL
+ * - MOV %reg, %reg
+ * - LEA 0(%reg),%reg
+ * - JMP +0
+ *
+ * Must not have false-positives; instructions identified as a NOP might be
+ * emulated as a NOP (uprobe) or Run Length Encoded in a larger NOP
+ * (alternatives).
+ *
+ * False-negatives are fine; need not be exhaustive.
+ */
+bool insn_is_nop(struct insn *insn)
+{
+ u8 b3 = 0, x3 = 0, r3 = 0;
+ u8 b4 = 0, x4 = 0, r4 = 0, m = 0;
+ u8 modrm, modrm_mod, modrm_reg, modrm_rm;
+ u8 sib = 0, sib_scale, sib_index, sib_base;
+ u8 nrex, rex;
+ u8 p, rep = 0;
+
+ if ((nrex = insn->rex_prefix.nbytes)) {
+ rex = insn->rex_prefix.bytes[nrex-1];
+
+ r3 = !!X86_REX_R(rex);
+ x3 = !!X86_REX_X(rex);
+ b3 = !!X86_REX_B(rex);
+ if (nrex > 1) {
+ r4 = !!X86_REX2_R(rex);
+ x4 = !!X86_REX2_X(rex);
+ b4 = !!X86_REX2_B(rex);
+ m = !!X86_REX2_M(rex);
+ }
+
+ } else if (insn->vex_prefix.nbytes) {
+ /*
+ * Ignore VEX encoded NOPs
+ */
+ return false;
+ }
+
+ if (insn->modrm.nbytes) {
+ modrm = insn->modrm.bytes[0];
+ modrm_mod = X86_MODRM_MOD(modrm);
+ modrm_reg = X86_MODRM_REG(modrm) + 8*r3 + 16*r4;
+ modrm_rm = X86_MODRM_RM(modrm) + 8*b3 + 16*b4;
+ modrm = 1;
+ }
+
+ if (insn->sib.nbytes) {
+ sib = insn->sib.bytes[0];
+ sib_scale = X86_SIB_SCALE(sib);
+ sib_index = X86_SIB_INDEX(sib) + 8*x3 + 16*x4;
+ sib_base = X86_SIB_BASE(sib) + 8*b3 + 16*b4;
+ sib = 1;
+
+ modrm_rm = sib_base;
+ }
+
+ for_each_insn_prefix(insn, p) {
+ if (p == 0xf3) /* REPE */
+ rep = 1;
+ }
+
+ /*
+ * Opcode map munging:
+ *
+ * REX2: 0 - single byte opcode
+ * 1 - 0f second byte opcode
+ */
+ switch (m) {
+ case 0: break;
+ case 1: insn->opcode.value <<= 8;
+ insn->opcode.value |= 0x0f;
+ break;
+ default:
+ return false;
+ }
+
+ switch (insn->opcode.bytes[0]) {
+ case 0x0f: /* 2nd byte */
+ break;
+
+ case 0x89: /* MOV */
+ if (modrm_mod != 3) /* register-direct */
+ return false;
+
+ /* native size */
+ if (insn->opnd_bytes != 4 * (1 + insn->x86_64))
+ return false;
+
+ return modrm_reg == modrm_rm; /* MOV %reg, %reg */
+
+ case 0x8d: /* LEA */
+ if (modrm_mod == 0 || modrm_mod == 3) /* register-indirect with disp */
+ return false;
+
+ /* native size */
+ if (insn->opnd_bytes != 4 * (1 + insn->x86_64))
+ return false;
+
+ if (insn->displacement.value != 0)
+ return false;
+
+ if (sib && (sib_scale != 0 || sib_index != 4)) /* (%reg, %eiz, 1) */
+ return false;
+
+ for_each_insn_prefix(insn, p) {
+ if (p != 0x3e) /* DS */
+ return false;
+ }
+
+ return modrm_reg == modrm_rm; /* LEA 0(%reg), %reg */
+
+ case 0x90: /* NOP */
+ if (b3 || b4) /* XCHG %r{8,16,24},%rax */
+ return false;
+
+ if (rep) /* REP NOP := PAUSE */
+ return false;
+
+ return true;
+
+ case 0xe9: /* JMP.d32 */
+ case 0xeb: /* JMP.d8 */
+ return insn->immediate.value == 0; /* JMP +0 */
+
+ default:
+ return false;
+ }
+
+ switch (insn->opcode.bytes[1]) {
+ case 0x1f:
+ return modrm_reg == 0; /* 0f 1f /0 -- NOPL */
+
+ default:
+ return false;
+ }
+}
diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c
index b5893928d55c..8c7cd115b484 100644
--- a/arch/x86/lib/kaslr.c
+++ b/arch/x86/lib/kaslr.c
@@ -22,7 +22,7 @@
#include <asm/setup.h>
#define debug_putstr(v) early_printk("%s", v)
-#define has_cpuflag(f) boot_cpu_has(f)
+#define has_cpuflag(f) cpu_feature_enabled(f)
#define get_boot_seed() kaslr_offset()
#endif
diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c
index 4ef7c6dcbea6..dfdd1da89f36 100644
--- a/arch/x86/lib/msr.c
+++ b/arch/x86/lib/msr.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
+#include <linux/kvm_types.h>
#include <linux/percpu.h>
#include <linux/preempt.h>
#include <asm/msr.h>
@@ -103,7 +104,7 @@ int msr_set_bit(u32 msr, u8 bit)
{
return __flip_bit(msr, bit, true);
}
-EXPORT_SYMBOL_GPL(msr_set_bit);
+EXPORT_SYMBOL_FOR_KVM(msr_set_bit);
/**
* msr_clear_bit - Clear @bit in a MSR @msr.
@@ -119,7 +120,7 @@ int msr_clear_bit(u32 msr, u8 bit)
{
return __flip_bit(msr, bit, false);
}
-EXPORT_SYMBOL_GPL(msr_clear_bit);
+EXPORT_SYMBOL_FOR_KVM(msr_clear_bit);
#ifdef CONFIG_TRACEPOINTS
void do_trace_write_msr(u32 msr, u64 val, int failed)
generated by cgit v1.2.3 (git 2.46.0) at 2025-12-03 20:08:40 +0000