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| author | Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> | 2011-04-28 07:08:36 +0900 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-05-22 08:39:58 -0400 |
| commit | 8f74d8e16812d63639871b4e56409b08bdcb66fc (patch) | |
| tree | 5004b63ab74194b615fc51c10528332e38a95348 | |
| parent | b74323dc2b7b5690d18bc7934b98e4665e778a7b (diff) | |
| download | linux-stable-8f74d8e16812d63639871b4e56409b08bdcb66fc.tar.gz linux-stable-8f74d8e16812d63639871b4e56409b08bdcb66fc.tar.bz2 linux-stable-8f74d8e16812d63639871b4e56409b08bdcb66fc.zip | |
KVM: MMU: Fix 64-bit paging breakage on x86_32
Fix regression introduced by
commit e30d2a170506830d5eef5e9d7990c5aedf1b0a51
KVM: MMU: Optimize guest page table walk
On x86_32, get_user() does not support 64-bit values and we fail to
build KVM at the point of 64-bit paging.
This patch fixes this by using get_user() twice for that condition.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Reported-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
| -rw-r--r-- | 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 652d56c081f7..52450a6b784f 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 (unlikely(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 (unlikely(get_user(pte, ptep_user))) { + if (unlikely(FNAME(read_gpte)(&pte, ptep_user))) { present = false; break; } |