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authorArnd Bergmann <arnd@arndb.de>2009-10-22 08:19:27 -0400
committerAvi Kivity <avi@redhat.com>2009-12-03 02:32:20 -0500
commit6ff5894cdfe7103083bd15b31002434ccd351039 (patch)
tree0e958c3b85712e2d1d320f4841e88ef8bdac8ea7 /virt/kvm/kvm_main.c
parentafbcf7ab8d1bc8c2d04792f6d9e786e0adeb328d (diff)
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/kvm/kvm_main.c')
-rw-r--r--virt/kvm/kvm_main.c51
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 @@
43#include <linux/swap.h> 43#include <linux/swap.h>
44#include <linux/bitops.h> 44#include <linux/bitops.h>
45#include <linux/spinlock.h> 45#include <linux/spinlock.h>
46#include <linux/compat.h>
46 47
47#include <asm/processor.h> 48#include <asm/processor.h>
48#include <asm/io.h> 49#include <asm/io.h>
@@ -1542,6 +1543,52 @@ out:
1542 return r; 1543 return r;
1543} 1544}
1544 1545
1546#ifdef CONFIG_COMPAT
1547struct compat_kvm_dirty_log {
1548 __u32 slot;
1549 __u32 padding1;
1550 union {
1551 compat_uptr_t dirty_bitmap; /* one bit per page */
1552 __u64 padding2;
1553 };
1554};
1555
1556static long kvm_vm_compat_ioctl(struct file *filp,
1557 unsigned int ioctl, unsigned long arg)
1558{
1559 struct kvm *kvm = filp->private_data;
1560 int r;
1561
1562 if (kvm->mm != current->mm)
1563 return -EIO;
1564 switch (ioctl) {
1565 case KVM_GET_DIRTY_LOG: {
1566 struct compat_kvm_dirty_log compat_log;
1567 struct kvm_dirty_log log;
1568
1569 r = -EFAULT;
1570 if (copy_from_user(&compat_log, (void __user *)arg,
1571 sizeof(compat_log)))
1572 goto out;
1573 log.slot = compat_log.slot;
1574 log.padding1 = compat_log.padding1;
1575 log.padding2 = compat_log.padding2;
1576 log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
1577
1578 r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
1579 if (r)
1580 goto out;
1581 break;
1582 }
1583 default:
1584 r = kvm_vm_ioctl(filp, ioctl, arg);
1585 }
1586
1587out:
1588 return r;
1589}
1590#endif
1591
1545static int kvm_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 1592static int kvm_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1546{ 1593{
1547 struct page *page[1]; 1594 struct page *page[1];
@@ -1576,7 +1623,9 @@ static int kvm_vm_mmap(struct file *file, struct vm_area_struct *vma)
1576static struct file_operations kvm_vm_fops = { 1623static struct file_operations kvm_vm_fops = {
1577 .release = kvm_vm_release, 1624 .release = kvm_vm_release,
1578 .unlocked_ioctl = kvm_vm_ioctl, 1625 .unlocked_ioctl = kvm_vm_ioctl,
1579 .compat_ioctl = kvm_vm_ioctl, 1626#ifdef CONFIG_COMPAT
1627 .compat_ioctl = kvm_vm_compat_ioctl,
1628#endif
1580 .mmap = kvm_vm_mmap, 1629 .mmap = kvm_vm_mmap,
1581}; 1630};
1582 1631