diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-12-12 10:12:53 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-12-16 17:53:38 +0100 |
| commit | 3f5ad8be3713572f3946b69eb376206153d0ea2d (patch) | |
| tree | 90ca8a72bf9fd7fc79652a8c772f00ae32574606 /arch/x86/kvm/hyperv.c | |
| parent | 83781d180b219bd079ae72b341ee3f21fb236e97 (diff) | |
KVM: hyperv: fix locking of struct kvm_hv fields
Introduce a new mutex to avoid an AB-BA deadlock between kvm->lock and
vcpu->mutex. Protect accesses in kvm_hv_setup_tsc_page too, as suggested
by Roman.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/hyperv.c')
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 99cde5220e07..1572c35b4f1a 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -852,6 +852,10 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE)) return; + mutex_lock(&kvm->arch.hyperv.hv_lock); + if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE)) + goto out_unlock; + gfn = hv->hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT; /* * Because the TSC parameters only vary when there is a @@ -859,7 +863,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, */ if (unlikely(kvm_read_guest(kvm, gfn_to_gpa(gfn), &tsc_seq, sizeof(tsc_seq)))) - return; + goto out_unlock; /* * While we're computing and writing the parameters, force the @@ -868,15 +872,15 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, hv->tsc_ref.tsc_sequence = 0; if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence))) - return; + goto out_unlock; if (!compute_tsc_page_parameters(hv_clock, &hv->tsc_ref)) - return; + goto out_unlock; /* Ensure sequence is zero before writing the rest of the struct. */ smp_wmb(); if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref))) - return; + goto out_unlock; /* * Now switch to the TSC page mechanism by writing the sequence. @@ -891,6 +895,8 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, hv->tsc_ref.tsc_sequence = tsc_seq; kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence)); +out_unlock: + mutex_unlock(&kvm->arch.hyperv.hv_lock); } static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data, @@ -1142,9 +1148,9 @@ int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) if (kvm_hv_msr_partition_wide(msr)) { int r; - mutex_lock(&vcpu->kvm->lock); + mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock); r = kvm_hv_set_msr_pw(vcpu, msr, data, host); - mutex_unlock(&vcpu->kvm->lock); + mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock); return r; } else return kvm_hv_set_msr(vcpu, msr, data, host); @@ -1155,9 +1161,9 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) if (kvm_hv_msr_partition_wide(msr)) { int r; - mutex_lock(&vcpu->kvm->lock); + mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock); r = kvm_hv_get_msr_pw(vcpu, msr, pdata); - mutex_unlock(&vcpu->kvm->lock); + mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock); return r; } else return kvm_hv_get_msr(vcpu, msr, pdata); @@ -1165,7 +1171,7 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) bool kvm_hv_hypercall_enabled(struct kvm *kvm) { - return kvm->arch.hyperv.hv_hypercall & HV_X64_MSR_HYPERCALL_ENABLE; + return READ_ONCE(kvm->arch.hyperv.hv_hypercall) & HV_X64_MSR_HYPERCALL_ENABLE; } static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result) |