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Commit 20b7035c authored by Jan H. Schönherr's avatar Jan H. Schönherr Committed by Paolo Bonzini
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KVM: Let KVM_SET_SIGNAL_MASK work as advertised 



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: default avatarJan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b7455825

arch/mips/kvm/mips.c

+2 −5
Original line number Diff line number Diff line
@@ -445,10 +445,8 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, 
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)

{

	int r = -EINTR;

	sigset_t sigsaved;



	if (vcpu->sigset_active)

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

	kvm_sigset_activate(vcpu);



	if (vcpu->mmio_needed) {

		if (!vcpu->mmio_is_write)
@@ -480,8 +478,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) 
	local_irq_enable();



out:

	if (vcpu->sigset_active)

		sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	kvm_sigset_deactivate(vcpu);



	return r;

}

arch/powerpc/kvm/powerpc.c

+2 −5
Original line number Diff line number Diff line
@@ -1407,7 +1407,6 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg) 
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)

{

	int r;

	sigset_t sigsaved;



	if (vcpu->mmio_needed) {

		vcpu->mmio_needed = 0;
@@ -1448,16 +1447,14 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) 
#endif

	}



	if (vcpu->sigset_active)

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

	kvm_sigset_activate(vcpu);



	if (run->immediate_exit)

		r = -EINTR;

	else

		r = kvmppc_vcpu_run(run, vcpu);



	if (vcpu->sigset_active)

		sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	kvm_sigset_deactivate(vcpu);



	return r;

}

arch/s390/kvm/kvm-s390.c

+2 −5
Original line number Diff line number Diff line
@@ -3372,7 +3372,6 @@ static void store_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

{

	int rc;

	sigset_t sigsaved;



	if (kvm_run->immediate_exit)

		return -EINTR;
@@ -3382,8 +3381,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
		return 0;

	}



	if (vcpu->sigset_active)

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

	kvm_sigset_activate(vcpu);



	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) {

		kvm_s390_vcpu_start(vcpu);
@@ -3417,8 +3415,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	disable_cpu_timer_accounting(vcpu);

	store_regs(vcpu, kvm_run);



	if (vcpu->sigset_active)

		sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	kvm_sigset_deactivate(vcpu);



	vcpu->stat.exit_userspace++;

	return rc;

arch/x86/kvm/x86.c

+2 −5
Original line number Diff line number Diff line
@@ -7267,12 +7267,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
{

	struct fpu *fpu = &current->thread.fpu;

	int r;

	sigset_t sigsaved;



	fpu__initialize(fpu);



	if (vcpu->sigset_active)

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

	kvm_sigset_activate(vcpu);



	if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) {

		if (kvm_run->immediate_exit) {
@@ -7315,8 +7313,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 


out:

	post_kvm_run_save(vcpu);

	if (vcpu->sigset_active)

		sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	kvm_sigset_deactivate(vcpu);



	return r;

}

include/linux/kvm_host.h

+3 −0
Original line number Diff line number Diff line
@@ -715,6 +715,9 @@ int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data, 
			 unsigned long len);

void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);



void kvm_sigset_activate(struct kvm_vcpu *vcpu);

void kvm_sigset_deactivate(struct kvm_vcpu *vcpu);



void kvm_vcpu_block(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu);