From fa3795a7308df099f0f2c9e5ca2c20a5ff65bdc4 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Mon, 11 Aug 2008 10:01:46 -0700 Subject: [PATCH] KVM: Reduce stack usage in kvm_vcpu_ioctl() Signed-off-by: Dave Hansen Signed-off-by: Avi Kivity --- virt/kvm/kvm_main.c | 50 +++++++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 20 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5eb96c7c8d7a..0309571fcb20 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1126,6 +1126,8 @@ static long kvm_vcpu_ioctl(struct file *filp, struct kvm_vcpu *vcpu = filp->private_data; void __user *argp = (void __user *)arg; int r; + struct kvm_fpu *fpu = NULL; + struct kvm_sregs *kvm_sregs = NULL; if (vcpu->kvm->mm != current->mm) return -EIO; @@ -1173,25 +1175,28 @@ out_free2: break; } case KVM_GET_SREGS: { - struct kvm_sregs kvm_sregs; - - memset(&kvm_sregs, 0, sizeof kvm_sregs); - r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, &kvm_sregs); + kvm_sregs = kzalloc(sizeof(struct kvm_sregs), GFP_KERNEL); + r = -ENOMEM; + if (!kvm_sregs) + goto out; + r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs); if (r) goto out; r = -EFAULT; - if (copy_to_user(argp, &kvm_sregs, sizeof kvm_sregs)) + if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs))) goto out; r = 0; break; } case KVM_SET_SREGS: { - struct kvm_sregs kvm_sregs; - - r = -EFAULT; - if (copy_from_user(&kvm_sregs, argp, sizeof kvm_sregs)) + kvm_sregs = kmalloc(sizeof(struct kvm_sregs), GFP_KERNEL); + r = -ENOMEM; + if (!kvm_sregs) goto out; - r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, &kvm_sregs); + r = -EFAULT; + if (copy_from_user(kvm_sregs, argp, sizeof(struct kvm_sregs))) + goto out; + r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs); if (r) goto out; r = 0; @@ -1272,25 +1277,28 @@ out_free2: break; } case KVM_GET_FPU: { - struct kvm_fpu fpu; - - memset(&fpu, 0, sizeof fpu); - r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, &fpu); + fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL); + r = -ENOMEM; + if (!fpu) + goto out; + r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu); if (r) goto out; r = -EFAULT; - if (copy_to_user(argp, &fpu, sizeof fpu)) + if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu))) goto out; r = 0; break; } case KVM_SET_FPU: { - struct kvm_fpu fpu; - - r = -EFAULT; - if (copy_from_user(&fpu, argp, sizeof fpu)) + fpu = kmalloc(sizeof(struct kvm_fpu), GFP_KERNEL); + r = -ENOMEM; + if (!fpu) goto out; - r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, &fpu); + r = -EFAULT; + if (copy_from_user(fpu, argp, sizeof(struct kvm_fpu))) + goto out; + r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu); if (r) goto out; r = 0; @@ -1300,6 +1308,8 @@ out_free2: r = kvm_arch_vcpu_ioctl(filp, ioctl, arg); } out: + kfree(fpu); + kfree(kvm_sregs); return r; }