diff options
| author | Roman Kagan <rkagan@virtuozzo.com> | 2017-07-14 17:13:20 +0300 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2017-07-14 16:28:18 +0200 |
| commit | d3457c877b14aaee8c52923eedf05a3b78af0476 (patch) | |
| tree | 619e33c612f455e8b15d22ce0eee536d657e50f3 /arch/x86/kvm/x86.c | |
| parent | 52a5c155cf79f1f059bffebf4d06d0249573e659 (diff) | |
| download | linux-d3457c877b14aaee8c52923eedf05a3b78af0476.tar.bz2 | |
kvm: x86: hyperv: make VP_INDEX managed by userspace
Hyper-V identifies vCPUs by Virtual Processor Index, which can be
queried via HV_X64_MSR_VP_INDEX msr. It is defined by the spec as a
sequential number which can't exceed the maximum number of vCPUs per VM.
APIC ids can be sparse and thus aren't a valid replacement for VP
indices.
Current KVM uses its internal vcpu index as VP_INDEX. However, to make
it predictable and persistent across VM migrations, the userspace has to
control the value of VP_INDEX.
This patch achieves that, by storing vp_index explicitly on vcpu, and
allowing HV_X64_MSR_VP_INDEX to be set from the host side. For
compatibility it's initialized to KVM vcpu index. Also a few variables
are renamed to make clear distinction betweed this Hyper-V vp_index and
KVM vcpu_id (== APIC id). Besides, a new capability,
KVM_CAP_HYPERV_VP_INDEX, is added to allow the userspace to skip
attempting msr writes where unsupported, to avoid spamming error logs.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6753f0982791..5b8f07889f6a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2666,6 +2666,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_HYPERV_SPIN: case KVM_CAP_HYPERV_SYNIC: case KVM_CAP_HYPERV_SYNIC2: + case KVM_CAP_HYPERV_VP_INDEX: case KVM_CAP_PCI_SEGMENT: case KVM_CAP_DEBUGREGS: case KVM_CAP_X86_ROBUST_SINGLESTEP: @@ -7688,6 +7689,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) struct msr_data msr; struct kvm *kvm = vcpu->kvm; + kvm_hv_vcpu_postcreate(vcpu); + if (vcpu_load(vcpu)) return; msr.data = 0x0; |