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Commit 7b914098 authored by Jes Sorensen's avatar Jes Sorensen Committed by Avi Kivity
Browse files

KVM: x86: Emulate MSR_EBC_FREQUENCY_ID 



Some operating systems store data about the host processor at the
time of installation, and when booted on a more uptodate cpu tries
to read MSR_EBC_FREQUENCY_ID. This has been found with XP.

Signed-off-by: default avatarJes Sorensen <Jes.Sorensen@redhat.com>
Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent b9a52c4b

arch/x86/kvm/x86.c

+14 −0
Original line number Diff line number Diff line
@@ -1651,6 +1651,20 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) 
	case 0xcd: /* fsb frequency */

		data = 3;

		break;

		/*

		 * MSR_EBC_FREQUENCY_ID

		 * Conservative value valid for even the basic CPU models.

		 * Models 0,1: 000 in bits 23:21 indicating a bus speed of

		 * 100MHz, model 2 000 in bits 18:16 indicating 100MHz,

		 * and 266MHz for model 3, or 4. Set Core Clock

		 * Frequency to System Bus Frequency Ratio to 1 (bits

		 * 31:24) even though these are only valid for CPU

		 * models > 2, however guests may end up dividing or

		 * multiplying by zero otherwise.

		 */

	case MSR_EBC_FREQUENCY_ID:

		data = 1 << 24;

		break;

	case MSR_IA32_APICBASE:

		data = kvm_get_apic_base(vcpu);

		break;