* MMU support
*
* Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affilates.
*
* Authors:
* Yaniv Kamay <yaniv@qumranet.com>
{
pt_element_t pte;
gfn_t table_gfn;
- unsigned index, pt_access, pte_access;
+ unsigned index, pt_access, uninitialized_var(pte_access);
gpa_t pte_gpa;
- int rsvd_fault = 0;
+ bool eperm, present, rsvd_fault;
trace_kvm_mmu_pagetable_walk(addr, write_fault, user_fault,
fetch_fault);
walk:
+ present = true;
+ eperm = rsvd_fault = false;
walker->level = vcpu->arch.mmu.root_level;
pte = vcpu->arch.cr3;
#if PTTYPE == 64
if (!is_long_mode(vcpu)) {
pte = kvm_pdptr_read(vcpu, (addr >> 30) & 3);
trace_kvm_mmu_paging_element(pte, walker->level);
- if (!is_present_gpte(pte))
- goto not_present;
+ if (!is_present_gpte(pte)) {
+ present = false;
+ goto error;
+ }
--walker->level;
}
#endif
walker->table_gfn[walker->level - 1] = table_gfn;
walker->pte_gpa[walker->level - 1] = pte_gpa;
- if (kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte)))
- goto not_present;
+ if (kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte))) {
+ present = false;
+ break;
+ }
trace_kvm_mmu_paging_element(pte, walker->level);
- if (!is_present_gpte(pte))
- goto not_present;
+ if (!is_present_gpte(pte)) {
+ present = false;
+ break;
+ }
- rsvd_fault = is_rsvd_bits_set(vcpu, pte, walker->level);
- if (rsvd_fault)
- goto access_error;
+ if (is_rsvd_bits_set(vcpu, pte, walker->level)) {
+ rsvd_fault = true;
+ break;
+ }
if (write_fault && !is_writable_pte(pte))
if (user_fault || is_write_protection(vcpu))
- goto access_error;
+ eperm = true;
if (user_fault && !(pte & PT_USER_MASK))
- goto access_error;
+ eperm = true;
#if PTTYPE == 64
if (fetch_fault && (pte & PT64_NX_MASK))
- goto access_error;
+ eperm = true;
#endif
- if (!(pte & PT_ACCESSED_MASK)) {
+ if (!eperm && !rsvd_fault && !(pte & PT_ACCESSED_MASK)) {
trace_kvm_mmu_set_accessed_bit(table_gfn, index,
sizeof(pte));
- mark_page_dirty(vcpu->kvm, table_gfn);
if (FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn,
index, pte, pte|PT_ACCESSED_MASK))
goto walk;
+ mark_page_dirty(vcpu->kvm, table_gfn);
pte |= PT_ACCESSED_MASK;
}
--walker->level;
}
+ if (!present || eperm || rsvd_fault)
+ goto error;
+
if (write_fault && !is_dirty_gpte(pte)) {
bool ret;
trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
- mark_page_dirty(vcpu->kvm, table_gfn);
ret = FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, index, pte,
pte|PT_DIRTY_MASK);
if (ret)
goto walk;
+ mark_page_dirty(vcpu->kvm, table_gfn);
pte |= PT_DIRTY_MASK;
walker->ptes[walker->level - 1] = pte;
}
walker->pt_access = pt_access;
walker->pte_access = pte_access;
pgprintk("%s: pte %llx pte_access %x pt_access %x\n",
- __func__, (u64)pte, pt_access, pte_access);
+ __func__, (u64)pte, pte_access, pt_access);
return 1;
-not_present:
+error:
walker->error_code = 0;
- goto err;
-
-access_error:
- walker->error_code = PFERR_PRESENT_MASK;
-
-err:
+ if (present)
+ walker->error_code |= PFERR_PRESENT_MASK;
if (write_fault)
walker->error_code |= PFERR_WRITE_MASK;
if (user_fault)
walker->error_code |= PFERR_USER_MASK;
- if (fetch_fault)
+ if (fetch_fault && is_nx(vcpu))
walker->error_code |= PFERR_FETCH_MASK;
if (rsvd_fault)
walker->error_code |= PFERR_RSVD_MASK;
return 0;
}
-static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
+static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
u64 *spte, const void *pte)
{
pt_element_t gpte;
gpte = *(const pt_element_t *)pte;
if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) {
if (!is_present_gpte(gpte)) {
- if (page->unsync)
+ if (sp->unsync)
new_spte = shadow_trap_nonpresent_pte;
else
new_spte = shadow_notrap_nonpresent_pte;
return;
}
pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
- pte_access = page->role.access & FNAME(gpte_access)(vcpu, gpte);
+ pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
if (gpte_to_gfn(gpte) != vcpu->arch.update_pte.gfn)
return;
pfn = vcpu->arch.update_pte.pfn;
* we call mmu_set_spte() with reset_host_protection = true beacuse that
* vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1).
*/
- mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,
- gpte & PT_DIRTY_MASK, NULL, PT_PAGE_TABLE_LEVEL,
+ mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
+ is_dirty_gpte(gpte), NULL, PT_PAGE_TABLE_LEVEL,
gpte_to_gfn(gpte), pfn, true, true);
}
+static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
+ struct guest_walker *gw, int level)
+{
+ int r;
+ pt_element_t curr_pte;
+
+ r = kvm_read_guest_atomic(vcpu->kvm, gw->pte_gpa[level - 1],
+ &curr_pte, sizeof(curr_pte));
+ return r || curr_pte != gw->ptes[level - 1];
+}
+
/*
* Fetch a shadow pte for a specific level in the paging hierarchy.
*/
int *ptwrite, pfn_t pfn)
{
unsigned access = gw->pt_access;
- struct kvm_mmu_page *shadow_page;
- u64 spte, *sptep = NULL;
- int direct;
- gfn_t table_gfn;
- int r;
- int level;
- pt_element_t curr_pte;
- struct kvm_shadow_walk_iterator iterator;
+ struct kvm_mmu_page *sp = NULL;
+ bool dirty = is_dirty_gpte(gw->ptes[gw->level - 1]);
+ int top_level;
+ unsigned direct_access;
+ struct kvm_shadow_walk_iterator it;
if (!is_present_gpte(gw->ptes[gw->level - 1]))
return NULL;
- for_each_shadow_entry(vcpu, addr, iterator) {
- level = iterator.level;
- sptep = iterator.sptep;
- if (iterator.level == hlevel) {
- mmu_set_spte(vcpu, sptep, access,
- gw->pte_access & access,
- user_fault, write_fault,
- gw->ptes[gw->level-1] & PT_DIRTY_MASK,
- ptwrite, level,
- gw->gfn, pfn, false, true);
- break;
- }
+ direct_access = gw->pt_access & gw->pte_access;
+ if (!dirty)
+ direct_access &= ~ACC_WRITE_MASK;
- if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
- continue;
+ top_level = vcpu->arch.mmu.root_level;
+ if (top_level == PT32E_ROOT_LEVEL)
+ top_level = PT32_ROOT_LEVEL;
+ /*
+ * Verify that the top-level gpte is still there. Since the page
+ * is a root page, it is either write protected (and cannot be
+ * changed from now on) or it is invalid (in which case, we don't
+ * really care if it changes underneath us after this point).
+ */
+ if (FNAME(gpte_changed)(vcpu, gw, top_level))
+ goto out_gpte_changed;
- if (is_large_pte(*sptep)) {
- rmap_remove(vcpu->kvm, sptep);
- __set_spte(sptep, shadow_trap_nonpresent_pte);
- kvm_flush_remote_tlbs(vcpu->kvm);
- }
+ for (shadow_walk_init(&it, vcpu, addr);
+ shadow_walk_okay(&it) && it.level > gw->level;
+ shadow_walk_next(&it)) {
+ gfn_t table_gfn;
- if (level <= gw->level) {
- int delta = level - gw->level + 1;
- direct = 1;
- if (!is_dirty_gpte(gw->ptes[level - delta]))
- access &= ~ACC_WRITE_MASK;
- table_gfn = gpte_to_gfn(gw->ptes[level - delta]);
- /* advance table_gfn when emulating 1gb pages with 4k */
- if (delta == 0)
- table_gfn += PT_INDEX(addr, level);
- access &= gw->pte_access;
- } else {
- direct = 0;
- table_gfn = gw->table_gfn[level - 2];
- }
- shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,
- direct, access, sptep);
- if (!direct) {
- r = kvm_read_guest_atomic(vcpu->kvm,
- gw->pte_gpa[level - 2],
- &curr_pte, sizeof(curr_pte));
- if (r || curr_pte != gw->ptes[level - 2]) {
- kvm_mmu_put_page(shadow_page, sptep);
- kvm_release_pfn_clean(pfn);
- sptep = NULL;
- break;
- }
+ drop_large_spte(vcpu, it.sptep);
+
+ sp = NULL;
+ if (!is_shadow_present_pte(*it.sptep)) {
+ table_gfn = gw->table_gfn[it.level - 2];
+ sp = kvm_mmu_get_page(vcpu, table_gfn, addr, it.level-1,
+ false, access, it.sptep);
}
- spte = __pa(shadow_page->spt)
- | PT_PRESENT_MASK | PT_ACCESSED_MASK
- | PT_WRITABLE_MASK | PT_USER_MASK;
- *sptep = spte;
+ /*
+ * Verify that the gpte in the page we've just write
+ * protected is still there.
+ */
+ if (FNAME(gpte_changed)(vcpu, gw, it.level - 1))
+ goto out_gpte_changed;
+
+ if (sp)
+ link_shadow_page(it.sptep, sp);
}
- return sptep;
+ for (;
+ shadow_walk_okay(&it) && it.level > hlevel;
+ shadow_walk_next(&it)) {
+ gfn_t direct_gfn;
+
+ validate_direct_spte(vcpu, it.sptep, direct_access);
+
+ drop_large_spte(vcpu, it.sptep);
+
+ if (is_shadow_present_pte(*it.sptep))
+ continue;
+
+ direct_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+
+ sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
+ true, direct_access, it.sptep);
+ link_shadow_page(it.sptep, sp);
+ }
+
+ mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access,
+ user_fault, write_fault, dirty, ptwrite, it.level,
+ gw->gfn, pfn, false, true);
+
+ return it.sptep;
+
+out_gpte_changed:
+ if (sp)
+ kvm_mmu_put_page(sp, it.sptep);
+ kvm_release_pfn_clean(pfn);
+ return NULL;
}
/*
pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
/* mmio */
- if (is_error_pfn(pfn)) {
- pgprintk("gfn %lx is mmio\n", walker.gfn);
- kvm_release_pfn_clean(pfn);
- return 1;
- }
+ if (is_error_pfn(pfn))
+ return kvm_handle_bad_page(vcpu->kvm, walker.gfn, pfn);
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
kvm_mmu_free_some_pages(vcpu);
sptep = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
level, &write_pt, pfn);
+ (void)sptep;
pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __func__,
sptep, *sptep, write_pt);
static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
{
struct kvm_shadow_walk_iterator iterator;
+ struct kvm_mmu_page *sp;
gpa_t pte_gpa = -1;
int level;
u64 *sptep;
level = iterator.level;
sptep = iterator.sptep;
+ sp = page_header(__pa(sptep));
if (is_last_spte(*sptep, level)) {
- struct kvm_mmu_page *sp = page_header(__pa(sptep));
int offset, shift;
+ if (!sp->unsync)
+ break;
+
shift = PAGE_SHIFT -
(PT_LEVEL_BITS - PT64_LEVEL_BITS) * level;
offset = sp->role.quadrant << shift;
pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
if (is_shadow_present_pte(*sptep)) {
- rmap_remove(vcpu->kvm, sptep);
if (is_large_pte(*sptep))
--vcpu->kvm->stat.lpages;
+ drop_spte(vcpu->kvm, sptep,
+ shadow_trap_nonpresent_pte);
need_flush = 1;
- }
- __set_spte(sptep, shadow_trap_nonpresent_pte);
+ } else
+ __set_spte(sptep, shadow_trap_nonpresent_pte);
break;
}
- if (!is_shadow_present_pte(*sptep))
+ if (!is_shadow_present_pte(*sptep) || !sp->unsync_children)
break;
}
* Using the cached information from sp->gfns is safe because:
* - The spte has a reference to the struct page, so the pfn for a given gfn
* can't change unless all sptes pointing to it are nuked first.
- * - Alias changes zap the entire shadow cache.
*/
-static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+ bool clear_unsync)
{
int i, offset, nr_present;
bool reset_host_protection;
offset = nr_present = 0;
+ /* direct kvm_mmu_page can not be unsync. */
+ BUG_ON(sp->role.direct);
+
if (PTTYPE == 32)
offset = sp->role.quadrant << PT64_LEVEL_BITS;
unsigned pte_access;
pt_element_t gpte;
gpa_t pte_gpa;
- gfn_t gfn = sp->gfns[i];
+ gfn_t gfn;
if (!is_shadow_present_pte(sp->spt[i]))
continue;
sizeof(pt_element_t)))
return -EINVAL;
- if (gpte_to_gfn(gpte) != gfn || !is_present_gpte(gpte) ||
- !(gpte & PT_ACCESSED_MASK)) {
+ gfn = gpte_to_gfn(gpte);
+ if (is_rsvd_bits_set(vcpu, gpte, PT_PAGE_TABLE_LEVEL)
+ || gfn != sp->gfns[i] || !is_present_gpte(gpte)
+ || !(gpte & PT_ACCESSED_MASK)) {
u64 nonpresent;
- rmap_remove(vcpu->kvm, &sp->spt[i]);
- if (is_present_gpte(gpte))
+ if (is_present_gpte(gpte) || !clear_unsync)
nonpresent = shadow_trap_nonpresent_pte;
else
nonpresent = shadow_notrap_nonpresent_pte;
- __set_spte(&sp->spt[i], nonpresent);
+ drop_spte(vcpu->kvm, &sp->spt[i], nonpresent);
continue;
}
projects / mirror_ubuntu-zesty-kernel.git / blobdiff