Commit 96e39ac0 authored Jul 25, 2013 by Jason Wang Committed by H. Peter Anvin Aug 05, 2013

x86: Introduce hypervisor_cpuid_base()

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: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: http://lkml.kernel.org/r/1374742475-2485-1-git-send-email-jasowang@redhat.com

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

parent c095ba72

arch/x86/include/asm/processor.h

+15 −0

Original line number	Diff line number	Diff line
		@@ -971,6 +971,21 @@ 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, signature[3];

		for (base = 0x40000000; base < 0x40010000; base += 0x100) {
		cpuid(base, &eax, &signature[0], &signature[1], &signature[2]);

		if (!memcmp(sig, signature, 12) &&
		(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);