On 04/26/2010 06:10 AM, Xiao Guangrong wrote:
Avi Kivity wrote:
On 04/25/2010 10:00 AM, Xiao Guangrong wrote:
If the guest is 32-bit, we should use 'quadrant' to adjust gpa
offset
Changlog v2:
- when level is PT_DIRECTORY_LEVEL, the 'offset' should be
'role.quadrant<< 8', thanks Avi for point it out
Signed-off-by: Xiao Guangrong<xiaoguangrong@xxxxxxxxxxxxxx>
---
arch/x86/kvm/paging_tmpl.h | 13 +++++++++++--
1 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index d0cc07e..83cc72f 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -478,9 +478,18 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu,
gva_t gva)
((level == PT_DIRECTORY_LEVEL&& is_large_pte(*sptep))) ||
((level == PT_PDPE_LEVEL&& is_large_pte(*sptep)))) {
struct kvm_mmu_page *sp = page_header(__pa(sptep));
-
+ int offset = 0;
+
+ if (PTTYPE == 32) {
+ if (level == PT_DIRECTORY_LEVEL)
+ offset = PAGE_SHIFT - 4;
+ else
+ offset = PT64_LEVEL_BITS;
+ offset = sp->role.quadrant<< offset;
+ }
The calculation is really
shift = (PT32_LEVEL_BITS - PT64_LEVEL_BITS) * level;
So, the offset is q<< (PAGE_SHIFT - (PT32_LEVEL_BITS - PT64_LEVEL_BITS) * level - 2)?
Ugh, what I meant was
shift = PAGE_SHIFT - (PT_LEVEL_BITS - PT64_LEVEL_BITS) * level;
offset = q << shift
so,
pte_gpa = (sp->gfn << PAGE_SHIFT) + offset + (spte - sp->spt) *
sizeof(pt_element_t)
No magic numbers please. Note it could work without the 'if (PTTYPE ==
32)'.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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