This patch introduce hypervisor_cpuid_base() which loop test the hypervisor
existence function until the signature match and check the number of leaves if
required. This could be used by Xen/KVM guest to detect the existence of
hypervisor.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: "Paolo Bonzini" <pbonzini@xxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
arch/x86/include/asm/processor.h | 20 ++++++++++++++++++++
1 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 24cf5ae..a8136d0 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -971,6 +971,26 @@ unsigned long calc_aperfmperf_ratio(struct aperfmperf *old,
return ratio;
}
+static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
+{
+ uint32_t base, eax, ebx, ecx, edx;
+ char signature[13];
+
+ for (base = 0x40000000; base < 0x40010000; base += 0x100) {
+ cpuid(base, &eax, &ebx, &ecx, &edx);
+ *(uint32_t *)(signature + 0) = ebx;
+ *(uint32_t *)(signature + 4) = ecx;
+ *(uint32_t *)(signature + 8) = edx;
+ signature[12] = 0;
+
+ if (!strcmp(sig, signature) &&
+ (leaves == 0 || ((eax - base) >= leaves)))
+ return base;
+ }
+
+ return 0;
+}
+
extern unsigned long arch_align_stack(unsigned long sp);
extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
--
1.7.1
--
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