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authorGlauber Costa <glommer@redhat.com>2010-05-11 12:17:43 -0400
committerAvi Kivity <avi@redhat.com>2010-05-19 11:41:03 +0300
commit84478c829d0f474a1d6749207c53daacc305d4e1 (patch)
treeb901fdad494f058ee43ee7946f77ab6922dc8a1b /arch/x86
parent0e6ac58acbcddbc9d1687214f0d43d8657cc036c (diff)
downloadop-kernel-dev-84478c829d0f474a1d6749207c53daacc305d4e1.zip
op-kernel-dev-84478c829d0f474a1d6749207c53daacc305d4e1.tar.gz
KVM: x86: export paravirtual cpuid flags in KVM_GET_SUPPORTED_CPUID
Right now, we were using individual KVM_CAP entities to communicate userspace about which cpuids we support. This is suboptimal, since it generates a delay between the feature arriving in the host, and being available at the guest. A much better mechanism is to list para features in KVM_GET_SUPPORTED_CPUID. This makes userspace automatically aware of what we provide. And if we ever add a new cpuid bit in the future, we have to do that again, which create some complexity and delay in feature adoption. Signed-off-by: Glauber Costa <glommer@redhat.com> Acked-by: Zachary Amsden <zamsden@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/x86.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 73d342c..419c451 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1972,6 +1972,23 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
}
break;
}
+ case KVM_CPUID_SIGNATURE: {
+ char signature[12] = "KVMKVMKVM\0\0";
+ u32 *sigptr = (u32 *)signature;
+ entry->eax = 0;
+ entry->ebx = sigptr[0];
+ entry->ecx = sigptr[1];
+ entry->edx = sigptr[2];
+ break;
+ }
+ case KVM_CPUID_FEATURES:
+ entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
+ (1 << KVM_FEATURE_NOP_IO_DELAY) |
+ (1 << KVM_FEATURE_CLOCKSOURCE2);
+ entry->ebx = 0;
+ entry->ecx = 0;
+ entry->edx = 0;
+ break;
case 0x80000000:
entry->eax = min(entry->eax, 0x8000001a);
break;
@@ -2018,6 +2035,23 @@ static int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
for (func = 0x80000001; func <= limit && nent < cpuid->nent; ++func)
do_cpuid_ent(&cpuid_entries[nent], func, 0,
&nent, cpuid->nent);
+
+
+
+ r = -E2BIG;
+ if (nent >= cpuid->nent)
+ goto out_free;
+
+ do_cpuid_ent(&cpuid_entries[nent], KVM_CPUID_SIGNATURE, 0, &nent,
+ cpuid->nent);
+
+ r = -E2BIG;
+ if (nent >= cpuid->nent)
+ goto out_free;
+
+ do_cpuid_ent(&cpuid_entries[nent], KVM_CPUID_FEATURES, 0, &nent,
+ cpuid->nent);
+
r = -E2BIG;
if (nent >= cpuid->nent)
goto out_free;
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