LoongArch: fix migrate issue

Upstream: no

when read_fault, we shoul't set the page _PAGE_WRITE.
this may case nest write fault issue.

Signed-off-by: Song Gao <gaosong@loongson.cn>
Change-Id: I443ac32d152c43635c0bafbe3da9b9479f4e546d
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>

Author: gaosong-loongson

arch/loongarch/include/asm/kvm_mmu.h

@@ -61,8 +61,7 @@ static inline void kvm_set_pte(kvm_pte_t *ptep, kvm_pte_t val)
 	WRITE_ONCE(*ptep, val);
 }
 
-static inline int kvm_pte_write(kvm_pte_t pte) { return pte & _PAGE_WRITE; }
-static inline int kvm_record_pte_write_able(kvm_pte_t pte) { return pte & KVM_RECORD_PAGE_WRITE_ABLE; }
+static inline int kvm_pte_write(kvm_pte_t pte) { return pte & KVM_RECORD_PAGE_WRITE_ABLE; }
 static inline int kvm_pte_dirty(kvm_pte_t pte) { return pte & _PAGE_DIRTY; }
 static inline int kvm_pte_young(kvm_pte_t pte) { return pte & _PAGE_ACCESSED; }
 static inline int kvm_pte_huge(kvm_pte_t pte) { return pte & _PAGE_HUGE; }
@@ -79,7 +78,12 @@ static inline kvm_pte_t kvm_pte_mkold(kvm_pte_t pte)
 
 static inline kvm_pte_t kvm_pte_mkdirty(kvm_pte_t pte)
 {
-	return pte | _PAGE_DIRTY;
+	return pte | _PAGE_DIRTY | _PAGE_WRITE;
+}
+
+static inline kvm_pte_t kvm_pte_mkwrite(kvm_pte_t pte)
+{
+	return pte | KVM_RECORD_PAGE_WRITE_ABLE;
 }
 
 static inline kvm_pte_t kvm_pte_mkclean(kvm_pte_t pte)

arch/loongarch/kvm/mmu.c

@@ -538,8 +538,10 @@ bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 	 * _PAGE_DIRTY since gpa has already recorded as dirty page
 	 */
 	prot_bits |= __WRITEABLE & *ptep & pte_val(range->arg.pte);
-	if (prot_bits & _PAGE_WRITE)
-		prot_bits |= KVM_RECORD_PAGE_WRITE_ABLE;
+	if (kvm_pte_dirty(prot_bits)) {
+		prot_bits = kvm_pte_mkclean(prot_bits);
+		prot_bits = kvm_pte_mkwrite(prot_bits);
+	}
 	kvm_set_pte(ptep, kvm_pfn_pte(pfn, __pgprot(prot_bits)));
 
 	return true;
@@ -605,15 +607,7 @@ static int kvm_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa, bool writ
 	/* Track access to pages marked old */
 	new = kvm_pte_mkyoung(*ptep);
 
-	/* We restore the write property of
-	 * the page table entry according to
-	 * KVM_RECORD_PAGE_WRITE_ABLE
-	 */
-	if (kvm_record_pte_write_able(new))
-		new |= _PAGE_WRITE;
-
 	/* call kvm_set_pfn_accessed() after unlock */
-
 	if (write && !kvm_pte_dirty(new)) {
 		if (!kvm_pte_write(new)) {
 			ret = -EFAULT;
@@ -918,9 +912,9 @@ static int kvm_map_page(struct kvm_vcpu *vcpu, unsigned long gpa, bool write)
 		 * to record it to restore the write attribute of the page entry,
 		 * in the fast path kvm_map_page_fast for page table processing
 		 */
-		prot_bits |= _PAGE_WRITE | KVM_RECORD_PAGE_WRITE_ABLE;
+		prot_bits = kvm_pte_mkwrite(prot_bits);
 		if (write)
-			prot_bits |= __WRITEABLE;
+			prot_bits = kvm_pte_mkdirty(prot_bits);
 	}
 
 	/* Disable dirty logging on HugePages */