KVM: MMU: remove bypass_guest_pf
The idea is from Avi:
| Maybe it's time to kill off bypass_guest_pf=1. It's not as effective as
| it used to be, since unsync pages always use shadow_trap_nonpresent_pte,
| and since we convert between the two nonpresent_ptes during sync and unsync.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 2f8543c..5334b4e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -186,8 +186,6 @@
static struct kmem_cache *mmu_page_header_cache;
static struct percpu_counter kvm_total_used_mmu_pages;
-static u64 __read_mostly shadow_trap_nonpresent_pte;
-static u64 __read_mostly shadow_notrap_nonpresent_pte;
static u64 __read_mostly shadow_nx_mask;
static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
static u64 __read_mostly shadow_user_mask;
@@ -199,13 +197,6 @@
return ((1ULL << (e - s + 1)) - 1) << s;
}
-void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
-{
- shadow_trap_nonpresent_pte = trap_pte;
- shadow_notrap_nonpresent_pte = notrap_pte;
-}
-EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
-
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
u64 dirty_mask, u64 nx_mask, u64 x_mask)
{
@@ -229,8 +220,7 @@
static int is_shadow_present_pte(u64 pte)
{
- return pte != shadow_trap_nonpresent_pte
- && pte != shadow_notrap_nonpresent_pte;
+ return pte & PT_PRESENT_MASK;
}
static int is_large_pte(u64 pte)
@@ -777,9 +767,9 @@
return 1;
}
-static void drop_spte(struct kvm *kvm, u64 *sptep, u64 new_spte)
+static void drop_spte(struct kvm *kvm, u64 *sptep)
{
- if (set_spte_track_bits(sptep, new_spte))
+ if (set_spte_track_bits(sptep, 0ull))
rmap_remove(kvm, sptep);
}
@@ -814,8 +804,7 @@
BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
if (is_writable_pte(*spte)) {
- drop_spte(kvm, spte,
- shadow_trap_nonpresent_pte);
+ drop_spte(kvm, spte);
--kvm->stat.lpages;
spte = NULL;
write_protected = 1;
@@ -836,7 +825,7 @@
while ((spte = rmap_next(kvm, rmapp, NULL))) {
BUG_ON(!(*spte & PT_PRESENT_MASK));
rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
- drop_spte(kvm, spte, shadow_trap_nonpresent_pte);
+ drop_spte(kvm, spte);
need_tlb_flush = 1;
}
return need_tlb_flush;
@@ -858,7 +847,7 @@
rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte);
need_flush = 1;
if (pte_write(*ptep)) {
- drop_spte(kvm, spte, shadow_trap_nonpresent_pte);
+ drop_spte(kvm, spte);
spte = rmap_next(kvm, rmapp, NULL);
} else {
new_spte = *spte &~ (PT64_BASE_ADDR_MASK);
@@ -1088,7 +1077,7 @@
u64 *parent_pte)
{
mmu_page_remove_parent_pte(sp, parent_pte);
- __set_spte(parent_pte, shadow_trap_nonpresent_pte);
+ __set_spte(parent_pte, 0ull);
}
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
@@ -1130,15 +1119,6 @@
kvm_mmu_mark_parents_unsync(sp);
}
-static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
- struct kvm_mmu_page *sp)
-{
- int i;
-
- for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
- sp->spt[i] = shadow_trap_nonpresent_pte;
-}
-
static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp)
{
@@ -1420,6 +1400,14 @@
}
}
+static void init_shadow_page_table(struct kvm_mmu_page *sp)
+{
+ int i;
+
+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
+ sp->spt[i] = 0ull;
+}
+
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
gfn_t gfn,
gva_t gaddr,
@@ -1482,10 +1470,7 @@
account_shadowed(vcpu->kvm, gfn);
}
- if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
- vcpu->arch.mmu.prefetch_page(vcpu, sp);
- else
- nonpaging_prefetch_page(vcpu, sp);
+ init_shadow_page_table(sp);
trace_kvm_mmu_get_page(sp, true);
return sp;
}
@@ -1546,7 +1531,7 @@
static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
{
if (is_large_pte(*sptep)) {
- drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
+ drop_spte(vcpu->kvm, sptep);
kvm_flush_remote_tlbs(vcpu->kvm);
}
}
@@ -1582,13 +1567,13 @@
pte = *spte;
if (is_shadow_present_pte(pte)) {
if (is_last_spte(pte, sp->role.level))
- drop_spte(kvm, spte, shadow_trap_nonpresent_pte);
+ drop_spte(kvm, spte);
else {
child = page_header(pte & PT64_BASE_ADDR_MASK);
drop_parent_pte(child, spte);
}
}
- __set_spte(spte, shadow_trap_nonpresent_pte);
+
if (is_large_pte(pte))
--kvm->stat.lpages;
}
@@ -1769,20 +1754,6 @@
__set_bit(slot, sp->slot_bitmap);
}
-static void mmu_convert_notrap(struct kvm_mmu_page *sp)
-{
- int i;
- u64 *pt = sp->spt;
-
- if (shadow_trap_nonpresent_pte == shadow_notrap_nonpresent_pte)
- return;
-
- for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
- if (pt[i] == shadow_notrap_nonpresent_pte)
- __set_spte(&pt[i], shadow_trap_nonpresent_pte);
- }
-}
-
/*
* The function is based on mtrr_type_lookup() in
* arch/x86/kernel/cpu/mtrr/generic.c
@@ -1895,7 +1866,6 @@
sp->unsync = 1;
kvm_mmu_mark_parents_unsync(sp);
- mmu_convert_notrap(sp);
}
static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn)
@@ -1980,7 +1950,7 @@
if (level > PT_PAGE_TABLE_LEVEL &&
has_wrprotected_page(vcpu->kvm, gfn, level)) {
ret = 1;
- drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
+ drop_spte(vcpu->kvm, sptep);
goto done;
}
@@ -2066,7 +2036,7 @@
} else if (pfn != spte_to_pfn(*sptep)) {
pgprintk("hfn old %llx new %llx\n",
spte_to_pfn(*sptep), pfn);
- drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
+ drop_spte(vcpu->kvm, sptep);
kvm_flush_remote_tlbs(vcpu->kvm);
} else
was_rmapped = 1;
@@ -2162,7 +2132,7 @@
spte = sp->spt + i;
for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
- if (*spte != shadow_trap_nonpresent_pte || spte == sptep) {
+ if (is_shadow_present_pte(*spte) || spte == sptep) {
if (!start)
continue;
if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
@@ -2214,7 +2184,7 @@
break;
}
- if (*iterator.sptep == shadow_trap_nonpresent_pte) {
+ if (!is_shadow_present_pte(*iterator.sptep)) {
u64 base_addr = iterator.addr;
base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
@@ -2748,7 +2718,6 @@
context->page_fault = nonpaging_page_fault;
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->invlpg = nonpaging_invlpg;
context->update_pte = nonpaging_update_pte;
@@ -2878,7 +2847,6 @@
context->new_cr3 = paging_new_cr3;
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->invlpg = paging64_invlpg;
context->update_pte = paging64_update_pte;
@@ -2907,7 +2875,6 @@
context->page_fault = paging32_page_fault;
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->invlpg = paging32_invlpg;
context->update_pte = paging32_update_pte;
@@ -2932,7 +2899,6 @@
context->new_cr3 = nonpaging_new_cr3;
context->page_fault = tdp_page_fault;
context->free = nonpaging_free;
- context->prefetch_page = nonpaging_prefetch_page;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
context->update_pte = nonpaging_update_pte;
@@ -3443,8 +3409,7 @@
continue;
if (is_large_pte(pt[i])) {
- drop_spte(kvm, &pt[i],
- shadow_trap_nonpresent_pte);
+ drop_spte(kvm, &pt[i]);
--kvm->stat.lpages;
continue;
}