[PATCH] KVM: MMU: Ignore pcd, pwt, and pat bits on ptes
The pcd, pwt, and pat bits on page table entries affect the cpu cache. Since
the cache is a host resource, the guest should not be able to control it.
Moreover, the meaning of these bits changes depending on whether pat is
enabled or not.
So, force these bits to zero on shadow page table entries at all times.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 765c2e1..a9771b4 100644
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -32,7 +32,6 @@
#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
#define PT_LEVEL_MASK(level) PT64_LEVEL_MASK(level)
#define PT_PTE_COPY_MASK PT64_PTE_COPY_MASK
- #define PT_NON_PTE_COPY_MASK PT64_NON_PTE_COPY_MASK
#elif PTTYPE == 32
#define pt_element_t u32
#define guest_walker guest_walker32
@@ -43,7 +42,6 @@
#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
#define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level)
#define PT_PTE_COPY_MASK PT32_PTE_COPY_MASK
- #define PT_NON_PTE_COPY_MASK PT32_NON_PTE_COPY_MASK
#else
#error Invalid PTTYPE value
#endif
@@ -105,9 +103,7 @@
if (PTTYPE == 32 && is_cpuid_PSE36())
gaddr |= (guest_pde & PT32_DIR_PSE36_MASK) <<
(32 - PT32_DIR_PSE36_SHIFT);
- *shadow_pte = (guest_pde & (PT_NON_PTE_COPY_MASK | PT_GLOBAL_MASK)) |
- ((guest_pde & PT_DIR_PAT_MASK) >>
- (PT_DIR_PAT_SHIFT - PT_PAT_SHIFT));
+ *shadow_pte = guest_pde & PT_PTE_COPY_MASK;
set_pte_common(vcpu, shadow_pte, gaddr,
guest_pde & PT_DIRTY_MASK, access_bits);
}
@@ -162,6 +158,7 @@
u32 index = SHADOW_PT_INDEX(addr, level);
u64 *shadow_ent = ((u64 *)__va(shadow_addr)) + index;
pt_element_t *guest_ent;
+ u64 shadow_pte;
if (is_present_pte(*shadow_ent) || is_io_pte(*shadow_ent)) {
if (level == PT_PAGE_TABLE_LEVEL)
@@ -204,14 +201,11 @@
shadow_addr = kvm_mmu_alloc_page(vcpu, shadow_ent);
if (!VALID_PAGE(shadow_addr))
return ERR_PTR(-ENOMEM);
- if (!kvm_arch_ops->is_long_mode(vcpu) && level == 3)
- *shadow_ent = shadow_addr |
- (*guest_ent & (PT_PRESENT_MASK | PT_PWT_MASK | PT_PCD_MASK));
- else {
- *shadow_ent = shadow_addr |
- (*guest_ent & PT_NON_PTE_COPY_MASK);
- *shadow_ent |= (PT_WRITABLE_MASK | PT_USER_MASK);
- }
+ shadow_pte = shadow_addr | PT_PRESENT_MASK;
+ if (vcpu->mmu.root_level > 3 || level != 3)
+ shadow_pte |= PT_ACCESSED_MASK
+ | PT_WRITABLE_MASK | PT_USER_MASK;
+ *shadow_ent = shadow_pte;
prev_shadow_ent = shadow_ent;
}
}