From c9d61dcb0bc26a761dc84a87bd8a0d3b3c432f10 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 22 Nov 2021 19:50:36 -0500 Subject: [PATCH] KVM: SEV: accept signals in sev_lock_two_vms Generally, kvm->lock is not taken for a long time, but sev_lock_two_vms is different: it takes vCPU locks inside, so userspace can hold it back just by calling a vCPU ioctl. Play it safe and use mutex_lock_killable. Message-Id: <20211123005036.2954379-13-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/sev.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index bbbf980..59727a96 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1547,6 +1547,7 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) { struct kvm_sev_info *dst_sev = &to_kvm_svm(dst_kvm)->sev_info; struct kvm_sev_info *src_sev = &to_kvm_svm(src_kvm)->sev_info; + int r = -EBUSY; if (dst_kvm == src_kvm) return -EINVAL; @@ -1558,14 +1559,23 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) if (atomic_cmpxchg_acquire(&dst_sev->migration_in_progress, 0, 1)) return -EBUSY; - if (atomic_cmpxchg_acquire(&src_sev->migration_in_progress, 0, 1)) { - atomic_set_release(&dst_sev->migration_in_progress, 0); - return -EBUSY; - } + if (atomic_cmpxchg_acquire(&src_sev->migration_in_progress, 0, 1)) + goto release_dst; - mutex_lock(&dst_kvm->lock); - mutex_lock(&src_kvm->lock); + r = -EINTR; + if (mutex_lock_killable(&dst_kvm->lock)) + goto release_src; + if (mutex_lock_killable(&src_kvm->lock)) + goto unlock_dst; return 0; + +unlock_dst: + mutex_unlock(&dst_kvm->lock); +release_src: + atomic_set_release(&src_sev->migration_in_progress, 0); +release_dst: + atomic_set_release(&dst_sev->migration_in_progress, 0); + return r; } static void sev_unlock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) -- 2.7.4