[PATCH 03/15] KVM: Add compat ioctl for KVM_SET_SIGNAL_MASK

Alexander Graf
2011-06-17T14:49:53Z

KVM has an ioctl to define which signal mask should be used while running
inside VCPU_RUN. At least for big endian systems, this mask is different
on 32-bit and 64-bit systems (though the size is identical).

Add a compat wrapper that converts the mask to whatever the kernel accepts,
allowing 32-bit kvm user space to set signal masks.

This patch fixes qemu with --enable-io-thread on ppc64 hosts when running
32-bit user land.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

- use compat_ptr
- only declare compat call with CONFIG_COMPAT
---
kernel/compat.c | 1 +
virt/kvm/kvm_main.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 52 insertions(+), 1 deletions(-)

diff --git a/kernel/compat.c b/kernel/compat.c
index fc9eb09..18197ae 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -890,6 +890,7 @@ sigset_from_compat (sigset_t *set, compat_sigset_t *compat)
case 1: set->sig[0] = compat->sig[0] | (((long)compat->sig[1]) << 32 );
}
}
+EXPORT_SYMBOL_GPL(sigset_from_compat);

asmlinkage long
compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fa2321a..11d2783 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -84,6 +84,10 @@ struct dentry *kvm_debugfs_dir;

static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
+#ifdef CONFIG_COMPAT
+static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
+ unsigned long arg);
+#endif
static int hardware_enable_all(void);
static void hardware_disable_all(void);

@@ -1586,7 +1590,9 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp)
static struct file_operations kvm_vcpu_fops = {
.release = kvm_vcpu_release,
.unlocked_ioctl = kvm_vcpu_ioctl,
- .compat_ioctl = kvm_vcpu_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = kvm_vcpu_compat_ioctl,
+#endif
.mmap = kvm_vcpu_mmap,
.llseek = noop_llseek,
};
@@ -1875,6 +1881,50 @@ out:
return r;
}

+#ifdef CONFIG_COMPAT
+static long kvm_vcpu_compat_ioctl(struct file *filp,
+ unsigned int ioctl, unsigned long arg)
+{
+ struct kvm_vcpu *vcpu = filp->private_data;
+ void __user *argp = compat_ptr(arg);
+ int r;
+
+ if (vcpu->kvm->mm != current->mm)
+ return -EIO;
+
+ switch (ioctl) {
+ case KVM_SET_SIGNAL_MASK: {
+ struct kvm_signal_mask __user *sigmask_arg = argp;
+ struct kvm_signal_mask kvm_sigmask;
+ compat_sigset_t csigset;
+ sigset_t sigset;
+
+ if (argp) {
+ r = -EFAULT;
+ if (copy_from_user(&kvm_sigmask, argp,
+ sizeof kvm_sigmask))
+ goto out;
+ r = -EINVAL;
+ if (kvm_sigmask.len != sizeof csigset)
+ goto out;
+ r = -EFAULT;
+ if (copy_from_user(&csigset, sigmask_arg->sigset,
+ sizeof csigset))
+ goto out;
+ }
+ sigset_from_compat(&sigset, &csigset);
+ r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
+ break;
+ }
+ default:
+ r = kvm_vcpu_ioctl(filp, ioctl, arg);
+ }
+
+out:
+ return r;
+}
+#endif
+
static long kvm_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
--
1.6.0.2