KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS
authorVitaly Kuznetsov <vkuznets@redhat.com>
Wed, 22 Aug 2018 10:18:28 +0000 (12:18 +0200)
committerPaolo Bonzini <pbonzini@redhat.com>
Tue, 16 Oct 2018 22:29:43 +0000 (00:29 +0200)
commit9170200ec0ebad70e5b9902bc93e2b1b11456a3b
tree2a935ca68f0dea412ba37fa77380cd6306583804
parent0624fca9512d08cbd9b5d098d904c840d3432404
KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS

Hyper-V TLFS (5.0b) states:

> Virtual processors are identified by using an index (VP index). The
> maximum number of virtual processors per partition supported by the
> current implementation of the hypervisor can be obtained through CPUID
> leaf 0x40000005. A virtual processor index must be less than the
> maximum number of virtual processors per partition.

Forbid userspace to set VP_INDEX above KVM_MAX_VCPUS. get_vcpu_by_vpidx()
can now be optimized to bail early when supplied vpidx is >= KVM_MAX_VCPUS.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
arch/x86/kvm/hyperv.c