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https://github.com/dynup/kpatch
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Merge pull request #453 from jpoimboe/rs-special-static
make _rs a "special" static local variable
This commit is contained in:
Seth Jennings
commit
664fb2a8a2
@ -515,76 +515,90 @@ struct kpatch_elf *kpatch_elf_open(const char *name)
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/*
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* This function detects whether the given symbol is a "special" static local
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* variable (for lack of a better term). If so, it returns the variable's
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* prefix string (with the trailing number removed).
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* variable (for lack of a better term).
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*
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* Special static local variables should never be correlated and should always
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* be included if they are referenced by an included function.
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*/
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char *special_static_prefix(struct symbol *sym)
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static int is_special_static(struct symbol *sym)
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{
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static char *prefixes[] = {
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"__key.",
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"__warned.",
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"descriptor.",
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"__func__.",
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"_rs.",
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NULL,
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};
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char **prefix;
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if (!sym)
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return NULL;
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if (sym->type == STT_OBJECT &&
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sym->bind == STB_LOCAL) {
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if (!strncmp(sym->name, "__key.", 6))
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return "__key.";
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if (!strncmp(sym->name, "__warned.", 9))
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return "__warned.";
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if (!strncmp(sym->name, "descriptor.", 11))
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return "descriptor.";
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if (!strncmp(sym->name, "__func__.", 9))
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return "__func__.";
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}
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return 0;
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if (sym->type == STT_SECTION) {
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if (!strncmp(sym->name, ".bss.__key.", 11))
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return ".bss.__key.";
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if (!strncmp(sym->name, ".rodata.__func__.", 17))
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return ".rodata.__func__.";
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/* __verbose section contains the descriptor variables */
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if (!strcmp(sym->name, "__verbose"))
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return sym->name;
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return 1;
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/* otherwise make sure section is bundled */
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if (!sym->sec->sym)
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return 0;
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/* use bundled object/function symbol for matching */
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sym = sym->sec->sym;
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}
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return NULL;
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if (sym->type != STT_OBJECT || sym->bind != STB_LOCAL)
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return 0;
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for (prefix = prefixes; *prefix; prefix++)
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if (!strncmp(sym->name, *prefix, strlen(*prefix)))
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return 1;
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return 0;
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}
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/*
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* This is like strcmp, but for gcc-mangled symbols. It skips the comparison
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* of any substring which consists of '.' followed by any number of digits.
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*/
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static int kpatch_mangled_strcmp(char *s1, char *s2)
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{
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while (*s1 == *s2) {
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if (!*s1)
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return 0;
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if (*s1 == '.' && isdigit(s1[1])) {
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if (!isdigit(s2[1]))
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return 1;
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while (isdigit(*++s1))
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;
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while (isdigit(*++s2))
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;
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} else {
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s1++;
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s2++;
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}
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}
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return 1;
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}
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int rela_equal(struct rela *rela1, struct rela *rela2)
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{
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char *prefix1, *prefix2;
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if (rela1->type != rela2->type ||
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rela1->offset != rela2->offset)
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return 0;
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if (rela1->string) {
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if (rela2->string &&
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!strcmp(rela1->string, rela2->string))
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return 1;
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} else {
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if (rela1->addend != rela2->addend)
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return 0;
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if (rela1->string)
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return rela2->string && !strcmp(rela1->string, rela2->string);
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prefix1 = special_static_prefix(rela1->sym);
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if (prefix1) {
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prefix2 = special_static_prefix(rela2->sym);
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if (!prefix2)
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return 0;
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return !strcmp(prefix1, prefix2);
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}
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if (rela1->addend != rela2->addend)
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return 0;
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if (!strcmp(rela1->sym->name, rela2->sym->name))
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return 1;
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}
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if (is_special_static(rela1->sym))
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return !kpatch_mangled_strcmp(rela1->sym->name,
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rela2->sym->name);
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return 0;
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return !strcmp(rela1->sym->name, rela2->sym->name);
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}
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void kpatch_compare_correlated_rela_section(struct section *sec)
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@ -831,7 +845,9 @@ void kpatch_correlate_sections(struct list_head *seclist1, struct list_head *sec
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if (strcmp(sec1->name, sec2->name))
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continue;
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if (special_static_prefix(sec1->secsym))
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if (is_special_static(is_rela_section(sec1) ?
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sec1->base->secsym :
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sec1->secsym))
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continue;
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/*
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@ -864,7 +880,7 @@ void kpatch_correlate_symbols(struct list_head *symlist1, struct list_head *syml
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sym1->type != sym2->type)
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continue;
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if (special_static_prefix(sym1))
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if (is_special_static(sym1))
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continue;
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/* group section symbols must have correlated sections */
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@ -940,30 +956,6 @@ void kpatch_mark_grouped_sections(struct kpatch_elf *kelf)
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}
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}
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/*
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* This is like strcmp, but for gcc-mangled symbols. It skips the comparison
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* of any substring which consists of '.' followed by any number of digits.
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*/
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static int kpatch_mangled_strcmp(char *s1, char *s2)
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{
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while (*s1 == *s2) {
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if (!*s1)
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return 0;
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if (*s1 == '.' && isdigit(s1[1])) {
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if (!isdigit(s2[1]))
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return 1;
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while (isdigit(*++s1))
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;
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while (isdigit(*++s2))
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;
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} else {
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s1++;
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s2++;
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}
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}
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return 1;
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}
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/*
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* When gcc makes compiler optimizations which affect a function's calling
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* interface, it mangles the function's name. For example, sysctl_print_dir is
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@ -1105,7 +1097,7 @@ void kpatch_correlate_static_local_variables(struct kpatch_elf *base,
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sym->twin)
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continue;
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if (special_static_prefix(sym))
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if (is_special_static(sym))
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continue;
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if (!strchr(sym->name, '.'))
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25
test/integration/special-static-2.patch
Normal file
25
test/integration/special-static-2.patch
Normal file
@ -0,0 +1,25 @@
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Index: src/arch/x86/kvm/x86.c
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===================================================================
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--- src.orig/arch/x86/kvm/x86.c
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+++ src/arch/x86/kvm/x86.c
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@@ -2011,12 +2011,20 @@ static void record_steal_time(struct kvm
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&vcpu->arch.st.steal, sizeof(struct kvm_steal_time));
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}
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+void kpatch_kvm_x86_foo(void)
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+{
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+ if (!jiffies)
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+ printk("kpatch kvm x86 foo\n");
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+}
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+
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int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
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{
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bool pr = false;
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u32 msr = msr_info->index;
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u64 data = msr_info->data;
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+ kpatch_kvm_x86_foo();
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+
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switch (msr) {
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case MSR_AMD64_NB_CFG:
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case MSR_IA32_UCODE_REV:
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