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[arch][x86][cpuid] clamp number of cpuid entries to read at boot

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Make sure we only read up to the max amount of cpuid values we have
preallocated in our static array.
This commit is contained in:
Travis Geiselbrecht
2022-10-18 23:56:52 -07:00
parent e02401e4bf
commit 5f9e6fdefc
1 changed files with 5 additions and 3 deletions
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8
arch/x86/feature.c
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@@ -107,7 +107,7 @@ static void x86_cpu_detect(void) {
// read the max basic cpuid leaf
cpuid(X86_CPUID_BASE, &a, &b, &c, &d);
max_cpuid_leaf = a;
max_cpuid_leaf = MIN(a, __X86_MAX_SUPPORTED_CPUID);;
// read the vendor string
union {
@@ -125,13 +125,15 @@ static void x86_cpu_detect(void) {
// read max extended cpuid leaf
cpuid(X86_CPUID_EXT_BASE, &a, &b, &c, &d);
if (a >= X86_CPUID_EXT_BASE) {
max_cpuid_leaf_ext = a;
max_cpuid_leaf_ext = MIN(a, __X86_MAX_SUPPORTED_CPUID_EXT);
}
// read max hypervisor leaf
cpuid(X86_CPUID_HYP_BASE, &a, &b, &c, &d);
// TODO: actually check that it's an understood hypervisor before setting this.
// It's possible on real hardware it's just returning the last valid regular cpuid.
if (a >= X86_CPUID_HYP_BASE) {
max_cpuid_leaf_hyp = a;
max_cpuid_leaf_hyp = MIN(a, __X86_MAX_SUPPORTED_CPUID_HYP);
}
} else {
__x86_cpu_vendor = X86_CPU_VENDOR_INTEL; // intrinsically Intel without cpuid