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authorMarcelo Tosatti <mtosatti@redhat.com>2008-09-23 13:18:33 -0300
committerAvi Kivity <avi@redhat.com>2008-10-15 14:25:19 +0200
commite8bc217aef67d41d767ede6e7a7eb10f1d47c86c (patch)
treef58c99dbf212d25d2fa8145ce46bc7ed5904cb07 /arch
parent38187c830cab84daecb41169948467f1f19317e3 (diff)
KVM: MMU: mode specific sync_page
Examine guest pagetable and bring the shadow back in sync. Caller is responsible for local TLB flush before re-entering guest mode. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/mmu.c10
-rw-r--r--arch/x86/kvm/paging_tmpl.h54
2 files changed, 64 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 731e6fe9cb0..90f01169c8f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -871,6 +871,12 @@ static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
sp->spt[i] = shadow_trap_nonpresent_pte;
}
+static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
+ struct kvm_mmu_page *sp)
+{
+ return 1;
+}
+
static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
{
unsigned index;
@@ -1547,6 +1553,7 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu)
context->gva_to_gpa = nonpaging_gva_to_gpa;
context->free = nonpaging_free;
context->prefetch_page = nonpaging_prefetch_page;
+ context->sync_page = nonpaging_sync_page;
context->root_level = 0;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
@@ -1594,6 +1601,7 @@ static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
context->page_fault = paging64_page_fault;
context->gva_to_gpa = paging64_gva_to_gpa;
context->prefetch_page = paging64_prefetch_page;
+ context->sync_page = paging64_sync_page;
context->free = paging_free;
context->root_level = level;
context->shadow_root_level = level;
@@ -1615,6 +1623,7 @@ static int paging32_init_context(struct kvm_vcpu *vcpu)
context->gva_to_gpa = paging32_gva_to_gpa;
context->free = paging_free;
context->prefetch_page = paging32_prefetch_page;
+ context->sync_page = paging32_sync_page;
context->root_level = PT32_ROOT_LEVEL;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
@@ -1634,6 +1643,7 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
context->page_fault = tdp_page_fault;
context->free = nonpaging_free;
context->prefetch_page = nonpaging_prefetch_page;
+ context->sync_page = nonpaging_sync_page;
context->shadow_root_level = kvm_x86_ops->get_tdp_level();
context->root_hpa = INVALID_PAGE;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index e9fbaa44d44..776fb6d2fd8 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -507,6 +507,60 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,
}
}
+/*
+ * 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)
+{
+ int i, offset, nr_present;
+
+ offset = nr_present = 0;
+
+ if (PTTYPE == 32)
+ offset = sp->role.quadrant << PT64_LEVEL_BITS;
+
+ for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
+ unsigned pte_access;
+ pt_element_t gpte;
+ gpa_t pte_gpa;
+ gfn_t gfn = sp->gfns[i];
+
+ if (!is_shadow_present_pte(sp->spt[i]))
+ continue;
+
+ pte_gpa = gfn_to_gpa(sp->gfn);
+ pte_gpa += (i+offset) * sizeof(pt_element_t);
+
+ if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
+ sizeof(pt_element_t)))
+ return -EINVAL;
+
+ if (gpte_to_gfn(gpte) != gfn || !is_present_pte(gpte) ||
+ !(gpte & PT_ACCESSED_MASK)) {
+ u64 nonpresent;
+
+ rmap_remove(vcpu->kvm, &sp->spt[i]);
+ if (is_present_pte(gpte))
+ nonpresent = shadow_trap_nonpresent_pte;
+ else
+ nonpresent = shadow_notrap_nonpresent_pte;
+ set_shadow_pte(&sp->spt[i], nonpresent);
+ continue;
+ }
+
+ nr_present++;
+ pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
+ set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,
+ is_dirty_pte(gpte), 0, gfn,
+ spte_to_pfn(sp->spt[i]), true);
+ }
+
+ return !nr_present;
+}
+
#undef pt_element_t
#undef guest_walker
#undef shadow_walker