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

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
......@@ -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;
......
......@@ -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:
;
}
......
......@@ -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
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