KVM: Add guest mode signal mask
Allow a special signal mask to be used while executing in guest mode. This allows signals to be used to interrupt a vcpu without requiring signal delivery to a userspace handler, which is quite expensive. Userspace still receives -EINTR and can get the signal via sigwait(). Signed-off-by: Avi Kivity <avi@qumranet.com>
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@@ -1591,9 +1591,13 @@ static void complete_pio(struct kvm_vcpu *vcpu)
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static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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{
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int r;
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sigset_t sigsaved;
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vcpu_load(vcpu);
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if (vcpu->sigset_active)
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sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
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/* re-sync apic's tpr */
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vcpu->cr8 = kvm_run->cr8;
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@@ -1616,6 +1620,9 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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r = kvm_arch_ops->run(vcpu, kvm_run);
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if (vcpu->sigset_active)
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sigprocmask(SIG_SETMASK, &sigsaved, NULL);
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vcpu_put(vcpu);
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return r;
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}
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@@ -2142,6 +2149,17 @@ out:
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return r;
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}
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static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)
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{
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if (sigset) {
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sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP));
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vcpu->sigset_active = 1;
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vcpu->sigset = *sigset;
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} else
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vcpu->sigset_active = 0;
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return 0;
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}
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static long kvm_vcpu_ioctl(struct file *filp,
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unsigned int ioctl, unsigned long arg)
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{
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@@ -2260,6 +2278,29 @@ static long kvm_vcpu_ioctl(struct file *filp,
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goto out;
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break;
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}
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case KVM_SET_SIGNAL_MASK: {
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struct kvm_signal_mask __user *sigmask_arg = argp;
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struct kvm_signal_mask kvm_sigmask;
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sigset_t sigset, *p;
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p = NULL;
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if (argp) {
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r = -EFAULT;
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if (copy_from_user(&kvm_sigmask, argp,
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sizeof kvm_sigmask))
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goto out;
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r = -EINVAL;
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if (kvm_sigmask.len != sizeof sigset)
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goto out;
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r = -EFAULT;
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if (copy_from_user(&sigset, sigmask_arg->sigset,
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sizeof sigset))
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goto out;
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p = &sigset;
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}
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r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
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break;
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}
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default:
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;
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}
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