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-rw-r--r--arch/x86/include/asm/kvm_host.h6
-rw-r--r--arch/x86/kvm/mmu.c62
-rw-r--r--arch/x86/kvm/paging_tmpl.h12
3 files changed, 32 insertions, 48 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3c9ea26c7aea..c1f19de8b51c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -239,6 +239,8 @@ struct kvm_mmu_page {
int clear_spte_count;
#endif
+ int write_flooding_count;
+
struct rcu_head rcu;
};
@@ -353,10 +355,6 @@ struct kvm_vcpu_arch {
struct kvm_mmu_memory_cache mmu_page_cache;
struct kvm_mmu_memory_cache mmu_page_header_cache;
- gfn_t last_pt_write_gfn;
- int last_pt_write_count;
- u64 *last_pte_updated;
-
struct fpu guest_fpu;
u64 xcr0;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ca6f72ab4c3b..e9534cec003f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1653,6 +1653,18 @@ static void init_shadow_page_table(struct kvm_mmu_page *sp)
sp->spt[i] = 0ull;
}
+static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp)
+{
+ sp->write_flooding_count = 0;
+}
+
+static void clear_sp_write_flooding_count(u64 *spte)
+{
+ struct kvm_mmu_page *sp = page_header(__pa(spte));
+
+ __clear_sp_write_flooding_count(sp);
+}
+
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
gfn_t gfn,
gva_t gaddr,
@@ -1696,6 +1708,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
} else if (sp->unsync)
kvm_mmu_mark_parents_unsync(sp);
+ __clear_sp_write_flooding_count(sp);
trace_kvm_mmu_get_page(sp, false);
return sp;
}
@@ -1848,15 +1861,6 @@ static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
mmu_page_remove_parent_pte(sp, parent_pte);
}
-static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
-{
- int i;
- struct kvm_vcpu *vcpu;
-
- kvm_for_each_vcpu(i, vcpu, kvm)
- vcpu->arch.last_pte_updated = NULL;
-}
-
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
{
u64 *parent_pte;
@@ -1916,7 +1920,6 @@ static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
}
sp->role.invalid = 1;
- kvm_mmu_reset_last_pte_updated(kvm);
return ret;
}
@@ -2361,8 +2364,6 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
}
}
kvm_release_pfn_clean(pfn);
- if (speculative)
- vcpu->arch.last_pte_updated = sptep;
}
static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
@@ -3523,13 +3524,6 @@ static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, bool zap_page,
kvm_mmu_flush_tlb(vcpu);
}
-static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
-{
- u64 *spte = vcpu->arch.last_pte_updated;
-
- return !!(spte && (*spte & shadow_accessed_mask));
-}
-
static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
const u8 *new, int *bytes)
{
@@ -3570,22 +3564,16 @@ static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
* If we're seeing too many writes to a page, it may no longer be a page table,
* or we may be forking, in which case it is better to unmap the page.
*/
-static bool detect_write_flooding(struct kvm_vcpu *vcpu, gfn_t gfn)
+static bool detect_write_flooding(struct kvm_mmu_page *sp, u64 *spte)
{
- bool flooded = false;
-
- if (gfn == vcpu->arch.last_pt_write_gfn
- && !last_updated_pte_accessed(vcpu)) {
- ++vcpu->arch.last_pt_write_count;
- if (vcpu->arch.last_pt_write_count >= 3)
- flooded = true;
- } else {
- vcpu->arch.last_pt_write_gfn = gfn;
- vcpu->arch.last_pt_write_count = 1;
- vcpu->arch.last_pte_updated = NULL;
- }
+ /*
+ * Skip write-flooding detected for the sp whose level is 1, because
+ * it can become unsync, then the guest page is not write-protected.
+ */
+ if (sp->role.level == 1)
+ return false;
- return flooded;
+ return ++sp->write_flooding_count >= 3;
}
/*
@@ -3657,7 +3645,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
LIST_HEAD(invalid_list);
u64 entry, gentry, *spte;
int npte;
- bool remote_flush, local_flush, zap_page, flooded, misaligned;
+ bool remote_flush, local_flush, zap_page;
/*
* If we don't have indirect shadow pages, it means no page is
@@ -3683,12 +3671,12 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
++vcpu->kvm->stat.mmu_pte_write;
trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
- flooded = detect_write_flooding(vcpu, gfn);
mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) {
- misaligned = detect_write_misaligned(sp, gpa, bytes);
+ spte = get_written_sptes(sp, gpa, &npte);
- if (misaligned || flooded) {
+ if (detect_write_misaligned(sp, gpa, bytes) ||
+ detect_write_flooding(sp, spte)) {
zap_page |= !!kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
&invalid_list);
++vcpu->kvm->stat.mmu_flooded;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 9efb86035774..52e9d58cec2b 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -497,6 +497,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
shadow_walk_next(&it)) {
gfn_t table_gfn;
+ clear_sp_write_flooding_count(it.sptep);
drop_large_spte(vcpu, it.sptep);
sp = NULL;
@@ -522,6 +523,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
shadow_walk_next(&it)) {
gfn_t direct_gfn;
+ clear_sp_write_flooding_count(it.sptep);
validate_direct_spte(vcpu, it.sptep, direct_access);
drop_large_spte(vcpu, it.sptep);
@@ -536,6 +538,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
link_shadow_page(it.sptep, sp);
}
+ clear_sp_write_flooding_count(it.sptep);
mmu_set_spte(vcpu, it.sptep, access, gw->pte_access,
user_fault, write_fault, emulate, it.level,
gw->gfn, pfn, prefault, map_writable);
@@ -599,11 +602,9 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
*/
if (!r) {
pgprintk("%s: guest page fault\n", __func__);
- if (!prefault) {
+ if (!prefault)
inject_page_fault(vcpu, &walker.fault);
- /* reset fork detector */
- vcpu->arch.last_pt_write_count = 0;
- }
+
return 0;
}
@@ -641,9 +642,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
pgprintk("%s: shadow pte %p %llx emulate %d\n", __func__,
sptep, *sptep, emulate);
- if (!emulate)
- vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
-
++vcpu->stat.pf_fixed;
trace_kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
spin_unlock(&vcpu->kvm->mmu_lock);
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-08 19:50:44 +0000