KVM: Add compat ioctl for KVM_SET_SIGNAL_MASK

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>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/kernel/compat.c b/kernel/compat.c
index fc9eb093acd5fc006e9f296b1a6c92b7a39d53ff..18197ae2d46544d09df56204e25fb50a142b150e 100644 (file)
--- 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 fa2321ac77ccf719e8a19fa5a8273145f24edd80..11d2783eb9dfbe887d31f755c884ce00eeb89436 100644 (file)
--- 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)
 {