On Tue, 26 Apr 2011 17:54:24 +0300
Avi Kivity <avi@xxxxxxxxxx> wrote:
> Please post a simple patch that uses two get_user()s for that case
> (64-bit pte on 32-bit host). Then work with the x86 tree to see if
> they'll accept 64-bit get_user(), and once they do, we can go back to a
> simple get_user() again.
>
I made a patch which seems to reflect what you said!
If this kind of fix is OK with you, I'll test on both x86_32 and x86_64,
and send the patch with some changelog tomorrow.
Thanks,
Takuya
---
arch/x86/kvm/paging_tmpl.h | 16 +++++++++++++++-
1 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index a32a1c8..1e44969 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -115,6 +115,20 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
return access;
}
+static int FNAME(read_gpte)(pt_element_t *pte, pt_element_t __user *ptep_user)
+{
+#if defined(CONFIG_X86_32) && (PTTYPE == 64)
+ u32 *p = (u32 *)pte;
+ u32 __user *p_user = (u32 __user *)ptep_user;
+
+ if (get_user(*p, p_user))
+ return -EFAULT;
+ return get_user(*(p + 1), p_user + 1);
+#else
+ return get_user(*pte, ptep_user);
+#endif
+}
+
/*
* Fetch a guest pte for a guest virtual address
*/
@@ -185,7 +199,7 @@ walk:
}
ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
- if (get_user(pte, ptep_user)) {
+ if (FNAME(read_gpte)(&pte, ptep_user)) {
present = false;
break;
}
--
1.7.1
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