Commit 9997cf7b authored Apr 15, 2016 by Eduardo Habkost

target-i386: Set AMD alias bits after filtering CPUID data



QEMU complains about -cpu host on an AMD machine:
  warning: host doesn't support requested feature: CPUID.80000001H:EDX [bit 0]
For bits 0,1,3,4,5,6,7,8,9,12,13,14,15,16,17,23,24.

KVM_GET_SUPPORTED_CPUID and and x86_cpu_get_migratable_flags()
don't handle the AMD CPUID aliases bits, making
x86_cpu_filter_features() print warnings and clear those CPUID
bits incorrectly.

To avoid hacking x86_cpu_get_migratable_flags() to handle
CPUID_EXT2_AMD_ALIASES (just like the existing hack inside
kvm_arch_get_supported_cpuid()), simply move the
CPUID_EXT2_AMD_ALIASES code in x86_cpu_realizefn() after the
x86_cpu_filter_features() call.

This will probably make the CPUID_EXT2_AMD_ALIASES hack in
kvm_arch_get_supported_cpuid() unnecessary, too. The hack will be
removed in a follow-up patch after v2.6.0.

Reported-by: Radim Krčmář <rkrcmar@redhat.com>
Tested-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

parent 92b674b6

target-i386/cpu.c

+8 −8

Original line number	Diff line number	Diff line
		@@ -2897,6 +2897,14 @@ static void x86_cpu_realizefn(DeviceState dev, Error *errp)
		env->cpuid_level = 7;
		}

		if (x86_cpu_filter_features(cpu) && cpu->enforce_cpuid) {
		error_setg(&local_err,
		kvm_enabled() ?
		"Host doesn't support requested features" :
		"TCG doesn't support requested features");
		goto out;
		}

		/* On AMD CPUs, some CPUID[8000_0001].EDX bits must match the bits on
		* CPUID[1].EDX.
		*/
		@@ -2907,14 +2915,6 @@ static void x86_cpu_realizefn(DeviceState dev, Error *errp)
		}


		if (x86_cpu_filter_features(cpu) && cpu->enforce_cpuid) {
		error_setg(&local_err,
		kvm_enabled() ?
		"Host doesn't support requested features" :
		"TCG doesn't support requested features");
		goto out;
		}

		#ifndef CONFIG_USER_ONLY
		qemu_register_reset(x86_cpu_machine_reset_cb, cpu);