From 20b7035c66bacc909ae3ffe92c1a1ea7db99fe4f Mon Sep 17 00:00:00 2001 From: "Jan H. Schönherr" Date: Fri, 24 Nov 2017 22:39:01 +0100 Subject: KVM: Let KVM_SET_SIGNAL_MASK work as advertised MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit KVM API says for the signal mask you set via KVM_SET_SIGNAL_MASK, that "any unblocked signal received [...] will cause KVM_RUN to return with -EINTR" and that "the signal will only be delivered if not blocked by the original signal mask". This, however, is only true, when the calling task has a signal handler registered for a signal. If not, signal evaluation is short-circuited for SIG_IGN and SIG_DFL, and the signal is either ignored without KVM_RUN returning or the whole process is terminated. Make KVM_SET_SIGNAL_MASK behave as advertised by utilizing logic similar to that in do_sigtimedwait() to avoid short-circuiting of signals. Signed-off-by: Jan H. Schönherr Signed-off-by: Paolo Bonzini --- virt/kvm/arm/arm.c | 8 +++----- virt/kvm/kvm_main.c | 23 +++++++++++++++++++++++ 2 files changed, 26 insertions(+), 5 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index a6524ff27de4..a67c106d73f5 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -615,7 +615,6 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu) int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) { int ret; - sigset_t sigsaved; if (unlikely(!kvm_vcpu_initialized(vcpu))) return -ENOEXEC; @@ -633,8 +632,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) if (run->immediate_exit) return -EINTR; - if (vcpu->sigset_active) - sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved); + kvm_sigset_activate(vcpu); ret = 1; run->exit_reason = KVM_EXIT_UNKNOWN; @@ -769,8 +767,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) kvm_pmu_update_run(vcpu); } - if (vcpu->sigset_active) - sigprocmask(SIG_SETMASK, &sigsaved, NULL); + kvm_sigset_deactivate(vcpu); + return ret; } diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2dd1a9ca4599..c01cff064ec5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2065,6 +2065,29 @@ void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn) } EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty); +void kvm_sigset_activate(struct kvm_vcpu *vcpu) +{ + if (!vcpu->sigset_active) + return; + + /* + * This does a lockless modification of ->real_blocked, which is fine + * because, only current can change ->real_blocked and all readers of + * ->real_blocked don't care as long ->real_blocked is always a subset + * of ->blocked. + */ + sigprocmask(SIG_SETMASK, &vcpu->sigset, ¤t->real_blocked); +} + +void kvm_sigset_deactivate(struct kvm_vcpu *vcpu) +{ + if (!vcpu->sigset_active) + return; + + sigprocmask(SIG_SETMASK, ¤t->real_blocked, NULL); + sigemptyset(¤t->real_blocked); +} + static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) { unsigned int old, val, grow; -- cgit v1.2.3-59-g8ed1b