Patchwork [10/15] i386: kvm: x2apic is not supported without in-kernel irqchip

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Submitter Eduardo Habkost
Date Oct. 4, 2012, 8:49 p.m.
Message ID <1349383747-19383-11-git-send-email-ehabkost@redhat.com>
Download mbox | patch
Permalink /patch/189342/
State New
Headers show

Comments

Eduardo Habkost - Oct. 4, 2012, 8:49 p.m.
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>
---
 target-i386/kvm.c | 7 +++++++
 1 file changed, 7 insertions(+)

Patch

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 704ad33..590f4d5 100644
--- 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: