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author | Arnd Bergmann <arnd@arndb.de> | 2009-10-22 14:19:27 +0200 |
---|---|---|
committer | Avi Kivity <avi@redhat.com> | 2009-12-03 09:32:20 +0200 |
commit | 6ff5894cdfe7103083bd15b31002434ccd351039 (patch) | |
tree | 0e958c3b85712e2d1d320f4841e88ef8bdac8ea7 /virt | |
parent | afbcf7ab8d1bc8c2d04792f6d9e786e0adeb328d (diff) | |
download | linux-stable-6ff5894cdfe7103083bd15b31002434ccd351039.tar.gz linux-stable-6ff5894cdfe7103083bd15b31002434ccd351039.tar.bz2 linux-stable-6ff5894cdfe7103083bd15b31002434ccd351039.zip |
KVM: Enable 32bit dirty log pointers on 64bit host
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.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r-- | virt/kvm/kvm_main.c | 51 |
1 files changed, 50 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index cac69c4415df..bd44fb48ac43 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -43,6 +43,7 @@ #include <linux/swap.h> #include <linux/bitops.h> #include <linux/spinlock.h> +#include <linux/compat.h> #include <asm/processor.h> #include <asm/io.h> @@ -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 +1623,9 @@ 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, +#ifdef CONFIG_COMPAT + .compat_ioctl = kvm_vm_compat_ioctl, +#endif .mmap = kvm_vm_mmap, }; |