i386: kvm: x2apic is not supported without in-kernel irqchip

This is necessary so that x2apic is not improperly enabled when the
in-kernel irqchip is disabled.

This won't generate a warning with "-cpu ...,check" because the current
check/enforce code is broken (it checks the host CPU data directly,
instead of using kvm_arch_get_supported_cpuid()), but it will be
eventually fixed to properly report the missing x2apic flag.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index aae8af22dd5b565a369fe1ff8a3fea9acd278d92..4e96b046da7d15c6cc9f65a4b394ea7c4cc7f11c 100644 (file)
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -209,6 +209,13 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
                 kvm_check_extension(s, KVM_CAP_TSC_DEADLINE_TIMER)) {
             ret |= CPUID_EXT_TSC_DEADLINE_TIMER;
         }
+
+        /* x2apic is reported by GET_SUPPORTED_CPUID, but it can't be enabled
+         * without the in-kernel irqchip
+         */
+        if (!kvm_irqchip_in_kernel()) {
+            ret &= ~CPUID_EXT_X2APIC;
+        }
     } else if (function == 0x80000001 && reg == R_EDX) {
         /* On Intel, kvm returns cpuid according to the Intel spec,
          * so add missing bits according to the AMD spec: