From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Date: Thu, 22 Oct 2009 12:19:27 +0000 Subject: [PATCH] Enable 32bit dirty log pointers on 64bit host Message-Id: <1256213967-701-1-git-send-email-agraf@suse.de> List-Id: References: <1256134109-14292-1-git-send-email-agraf@suse.de> In-Reply-To: <1256134109-14292-1-git-send-email-agraf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Avi Kivity , kvm-ppc , Arnd Bergmann From: Arnd Bergmann With big endian userspace, we can't quite figure out if a pointer is 32 bit (shifted >> 32) or 64 bit when we read a 64 bit pointer. This is what happens with dirty logging. To get the pointer interpreted correctly, we thus need Arnd's patch to implement a compat layer for the ioctl: A better way to do this is to add a separate compat_ioctl() method that converts this for you. Based on initial patch from Arnd Bergmann. From: Arnd Bergmann Signed-off-by: Arnd Bergmann Signed-off-by: Alexander Graf --- Changes from Arnd's example version: - s/log.log/log/ (Avi) - use sizeof(compat_log) (Avi) - compile fixes --- virt/kvm/kvm_main.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 48 insertions(+), 1 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index cac69c4..54a272f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -1542,6 +1543,52 @@ out: return r; } +#ifdef CONFIG_COMPAT +struct compat_kvm_dirty_log { + __u32 slot; + __u32 padding1; + union { + compat_uptr_t dirty_bitmap; /* one bit per page */ + __u64 padding2; + }; +}; + +static long kvm_vm_compat_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm *kvm = filp->private_data; + int r; + + if (kvm->mm != current->mm) + return -EIO; + switch (ioctl) { + case KVM_GET_DIRTY_LOG: { + struct compat_kvm_dirty_log compat_log; + struct kvm_dirty_log log; + + r = -EFAULT; + if (copy_from_user(&compat_log, (void __user *)arg, + sizeof(compat_log))) + goto out; + log.slot = compat_log.slot; + log.padding1 = compat_log.padding1; + log.padding2 = compat_log.padding2; + log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap); + + r = kvm_vm_ioctl_get_dirty_log(kvm, &log); + if (r) + goto out; + break; + } + default: + r = kvm_vm_ioctl(filp, ioctl, arg); + } + +out: + return r; +} +#endif + static int kvm_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { struct page *page[1]; @@ -1576,7 +1623,7 @@ static int kvm_vm_mmap(struct file *file, struct vm_area_struct *vma) static struct file_operations kvm_vm_fops = { .release = kvm_vm_release, .unlocked_ioctl = kvm_vm_ioctl, - .compat_ioctl = kvm_vm_ioctl, + .compat_ioctl = kvm_vm_compat_ioctl, .mmap = kvm_vm_mmap, }; -- 1.6.0.2