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| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2018-09-26 19:02:56 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-10-17 00:29:45 +0200 |
| commit | 87ee613d076351950b74383215437f841ebbeb75 (patch) | |
| tree | ec82161513eceed1cd7291331c703b443bb6f2be /arch | |
| parent | 1779a39f786397760ae7a7cc03cf37697d8ae58d (diff) | |
| download | linux-stable-87ee613d076351950b74383215437f841ebbeb75.tar.gz linux-stable-87ee613d076351950b74383215437f841ebbeb75.tar.bz2 linux-stable-87ee613d076351950b74383215437f841ebbeb75.zip | |
KVM: x86: hyperv: keep track of mismatched VP indexes
In most common cases VP index of a vcpu matches its vcpu index. Userspace
is, however, free to set any mapping it wishes and we need to account for
that when we need to find a vCPU with a particular VP index. To keep search
algorithms optimal in both cases introduce 'num_mismatched_vp_indexes'
counter showing how many vCPUs with mismatching VP index we have. In case
the counter is zero we can assume vp_index == vcpu_idx.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 3 | ||||
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 26 |
2 files changed, 26 insertions, 3 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ed4d7848ebf2..d81f536d024a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -790,6 +790,9 @@ struct kvm_hv { u64 hv_reenlightenment_control; u64 hv_tsc_emulation_control; u64 hv_tsc_emulation_status; + + /* How many vCPUs have VP index != vCPU index */ + atomic_t num_mismatched_vp_indexes; }; enum kvm_irqchip_mode { diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index c8764faf783b..f94dedd7ae6d 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1045,11 +1045,31 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv; switch (msr) { - case HV_X64_MSR_VP_INDEX: - if (!host || (u32)data >= KVM_MAX_VCPUS) + case HV_X64_MSR_VP_INDEX: { + struct kvm_hv *hv = &vcpu->kvm->arch.hyperv; + int vcpu_idx = kvm_vcpu_get_idx(vcpu); + u32 new_vp_index = (u32)data; + + if (!host || new_vp_index >= KVM_MAX_VCPUS) return 1; - hv_vcpu->vp_index = (u32)data; + + if (new_vp_index == hv_vcpu->vp_index) + return 0; + + /* + * The VP index is initialized to vcpu_index by + * kvm_hv_vcpu_postcreate so they initially match. Now the + * VP index is changing, adjust num_mismatched_vp_indexes if + * it now matches or no longer matches vcpu_idx. + */ + if (hv_vcpu->vp_index == vcpu_idx) + atomic_inc(&hv->num_mismatched_vp_indexes); + else if (new_vp_index == vcpu_idx) + atomic_dec(&hv->num_mismatched_vp_indexes); + + hv_vcpu->vp_index = new_vp_index; break; + } case HV_X64_MSR_VP_ASSIST_PAGE: { u64 gfn; unsigned long addr; |