diff options
| author | Glauber Costa <glommer@redhat.com> | 2010-05-11 18:17:43 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-05-19 10:41:03 +0200 |
| commit | 84478c829d0f474a1d6749207c53daacc305d4e1 (patch) | |
| tree | b901fdad494f058ee43ee7946f77ab6922dc8a1b | |
| parent | KVM: x86: add new KVMCLOCK cpuid feature (diff) | |
| download | linux-84478c829d0f474a1d6749207c53daacc305d4e1.tar.xz linux-84478c829d0f474a1d6749207c53daacc305d4e1.zip | |
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>
| -rw-r--r-- | arch/x86/kvm/x86.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 73d342c69ed4..419c4512e270 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; |