DEEPIN: LoongArch: KVM: enable ptw for kvm

Upstream: no

Add the ptw feature bit to cpucfg

Signed-off-by: Xianglai Li <[email protected]>
Link: deepin-community/kernel@bc32c6c9c36d
Link: https://git.kernel.org/torvalds/c/f3b65bbaed7c # conflict
Signed-off-by: Xi Ruoyao <[email protected]>

Author: lixianglai

arch/loongarch/include/asm/kvm_mmu.h

@@ -18,6 +18,15 @@
 
 #define _KVM_FLUSH_PGTABLE	0x1
 #define _KVM_HAS_PGMASK		0x2
+
+/* If the page entry has a write attribute,
+ * we use the page entry 50bit(KVM_RECORD_PAGE_WRITE_ABLE)
+ * to record it to restore the write attribute of the page entry,
+ * in the fast path kvm_map_page_fast for page table processing
+ */
+#define	KVM_RECORD_PAGE_WRITE_ABLE_SHIFT	50
+#define KVM_RECORD_PAGE_WRITE_ABLE		(_ULCAST_(1) << KVM_RECORD_PAGE_WRITE_ABLE_SHIFT)
+
 #define kvm_pfn_pte(pfn, prot)	(((pfn) << PFN_PTE_SHIFT) | pgprot_val(prot))
 #define kvm_pte_pfn(x)		((phys_addr_t)((x & _PFN_MASK) >> PFN_PTE_SHIFT))
 
@@ -53,6 +62,7 @@ static inline void kvm_set_pte(kvm_pte_t *ptep, kvm_pte_t 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_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; }
@@ -74,7 +84,7 @@ static inline kvm_pte_t kvm_pte_mkdirty(kvm_pte_t pte)
 
 static inline kvm_pte_t kvm_pte_mkclean(kvm_pte_t pte)
 {
-	return pte & ~_PAGE_DIRTY;
+	return pte & (~(_PAGE_DIRTY | _PAGE_WRITE));
 }
 
 static inline kvm_pte_t kvm_pte_mkhuge(kvm_pte_t pte)

arch/loongarch/kvm/exit.c

@@ -44,6 +44,8 @@ static int kvm_emu_cpucfg(struct kvm_vcpu *vcpu, larch_inst inst)
 	switch (index) {
 	case 0 ... (KVM_MAX_CPUCFG_REGS - 1):
 		vcpu->arch.gprs[rd] = vcpu->arch.cpucfg[index];
+		if (cpu_has_ptw && (index == LOONGARCH_CPUCFG2))
+			vcpu->arch.gprs[rd] |= CPUCFG2_PTW;
 		break;
 	case CPUCFG_KVM_SIG:
 		/* CPUCFG emulation between 0x40000000 -- 0x400000ff */

arch/loongarch/kvm/mmu.c

@@ -568,6 +568,14 @@ 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;
+
 	if (write && !kvm_pte_dirty(new)) {
 		if (!kvm_pte_write(new)) {
 			ret = -EFAULT;
@@ -856,7 +864,12 @@ static int kvm_map_page(struct kvm_vcpu *vcpu, unsigned long gpa, bool write)
 		prot_bits |= _CACHE_SUC;
 
 	if (writeable) {
-		prot_bits |= _PAGE_WRITE;
+		/* If the page entry has a write attribute,
+		 * we use the page entry 50bit(KVM_RECORD_PAGE_WRITE_ABLE)
+		 * 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;
 		if (write)
 			prot_bits |= __WRITEABLE;
 	}