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Commit 1961d276 authored by Avi Kivity's avatar Avi Kivity
Browse files

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: default avatarAvi Kivity <avi@qumranet.com>
parent 6722c51c

drivers/kvm/kvm.h

+3 −0
Original line number Diff line number Diff line
@@ -277,6 +277,9 @@ struct kvm_vcpu { 
	gpa_t mmio_phys_addr;

	int pio_pending;



	int sigset_active;

	sigset_t sigset;



	struct {

		int active;

		u8 save_iopl;

drivers/kvm/kvm_main.c

+41 −0
Original line number Diff line number Diff line
@@ -1591,9 +1591,13 @@ static void complete_pio(struct kvm_vcpu *vcpu) 
static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

{

	int r;

	sigset_t sigsaved;



	vcpu_load(vcpu);



	if (vcpu->sigset_active)

		sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);



	/* re-sync apic's tpr */

	vcpu->cr8 = kvm_run->cr8;
@@ -1616,6 +1620,9 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 


	r = kvm_arch_ops->run(vcpu, kvm_run);



	if (vcpu->sigset_active)

		sigprocmask(SIG_SETMASK, &sigsaved, NULL);



	vcpu_put(vcpu);

	return r;

}
@@ -2142,6 +2149,17 @@ static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, 
	return r;

}



static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)

{

	if (sigset) {

		sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP));

		vcpu->sigset_active = 1;

		vcpu->sigset = *sigset;

	} else

		vcpu->sigset_active = 0;

	return 0;

}



static long kvm_vcpu_ioctl(struct file *filp,

			   unsigned int ioctl, unsigned long arg)

{
@@ -2260,6 +2278,29 @@ static long kvm_vcpu_ioctl(struct file *filp, 
			goto out;

		break;

	}

	case KVM_SET_SIGNAL_MASK: {

		struct kvm_signal_mask __user *sigmask_arg = argp;

		struct kvm_signal_mask kvm_sigmask;

		sigset_t sigset, *p;



		p = NULL;

		if (argp) {

			r = -EFAULT;

			if (copy_from_user(&kvm_sigmask, argp,

					   sizeof kvm_sigmask))

				goto out;

			r = -EINVAL;

			if (kvm_sigmask.len != sizeof sigset)

				goto out;

			r = -EFAULT;

			if (copy_from_user(&sigset, sigmask_arg->sigset,

					   sizeof sigset))

				goto out;

			p = &sigset;

		}

		r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);

		break;

	}

	default:

		;

	}

include/linux/kvm.h

+7 −0
Original line number Diff line number Diff line
@@ -234,6 +234,12 @@ struct kvm_cpuid { 
	struct kvm_cpuid_entry entries[0];

};



/* for KVM_SET_SIGNAL_MASK */

struct kvm_signal_mask {

	__u32 len;

	__u8  sigset[0];

};



#define KVMIO 0xAE



/*
@@ -273,5 +279,6 @@ struct kvm_cpuid { 
#define KVM_GET_MSRS              _IOWR(KVMIO, 0x88, struct kvm_msrs)

#define KVM_SET_MSRS              _IOW(KVMIO,  0x89, struct kvm_msrs)

#define KVM_SET_CPUID             _IOW(KVMIO,  0x8a, struct kvm_cpuid)

#define KVM_SET_SIGNAL_MASK       _IOW(KVMIO,  0x8b, struct kvm_signal_mask)



#endif