[PATCH v5 08/14] nEPT: Redefine EPT-specific link_shadow_page()

Gleb Natapov
2013-07-31T14:49:07Z

From: Yang Zhang <yang.z.zhang@Intel.com>

Since nEPT doesn't support A/D bit, so we should not set those bit
when build shadow page table.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
arch/x86/kvm/mmu.c | 12 +++++++++---
arch/x86/kvm/paging_tmpl.h | 4 ++--
2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b5273c3..9e0f467 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2047,12 +2047,18 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
return __shadow_walk_next(iterator, *iterator->sptep);
}

-static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
+static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp, bool accessed)
{
u64 spte;

+ BUILD_BUG_ON(VMX_EPT_READABLE_MASK != PT_PRESENT_MASK ||
+ VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);
+
spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK |
- shadow_user_mask | shadow_x_mask | shadow_accessed_mask;
+ shadow_user_mask | shadow_x_mask;
+
+ if (accessed)
+ spte |= shadow_accessed_mask;

mmu_spte_set(sptep, spte);
}
@@ -2677,7 +2683,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
iterator.level - 1,
1, ACC_ALL, iterator.sptep);

- link_shadow_page(iterator.sptep, sp);
+ link_shadow_page(iterator.sptep, sp, true);
}
}
return emulate;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 762c904..0d25351 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -555,7 +555,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
goto out_gpte_changed;

if (sp)
- link_shadow_page(it.sptep, sp);
+ link_shadow_page(it.sptep, sp, PTTYPE != PTTYPE_EPT);
}

for (;
@@ -575,7 +575,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,

sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
true, direct_access, it.sptep);
- link_shadow_page(it.sptep, sp);
+ link_shadow_page(it.sptep, sp, PTTYPE != PTTYPE_EPT);
}

clear_sp_write_flooding_count(it.sptep);
--
1.7.10.4