LoongArch: KVM: Add dirty bitmap initially all set support

Add KVM_DIRTY_LOG_INITIALLY_SET support on LoongArch system, this
feature comes from other architectures like x86 and arm64.

Signed-off-by: Bibo Mao <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>

Author: bibo-mao

arch/loongarch/include/asm/kvm_host.h

@@ -37,6 +37,9 @@
 #define KVM_GUESTDBG_VALID_MASK		\
 	(KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP | KVM_GUESTDBG_SINGLESTEP)
 
+#define KVM_DIRTY_LOG_MANUAL_CAPS	\
+	(KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | KVM_DIRTY_LOG_INITIALLY_SET)
+
 struct kvm_vm_stat {
 	struct kvm_vm_stat_generic generic;
 	u64 pages;

arch/loongarch/kvm/mmu.c

@@ -467,6 +467,13 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 	 *		kvm_arch_flush_shadow_memslot()
 	 */
 	if (!(old_flags & KVM_MEM_LOG_DIRTY_PAGES) && log_dirty_pages) {
+		/*
+		 * Initially-all-set does not require write protecting any page
+		 * because they're all assumed to be dirty.
+		 */
+		if (kvm_dirty_log_manual_protect_and_init_set(kvm))
+			return;
+
 		spin_lock(&kvm->mmu_lock);
 		/* Write protect GPA page table entries */
 		needs_flush = kvm_mkclean_gpa_pt(kvm, new->base_gfn,