[PATCH v2 4/7] KVM: MMU: enable KVM_WRITE_PROTECT_ALL_MEM

[guangrong . xiao]

From: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxx>

The functionality of write protection for all guest memory is ready,
it is the time to make its usable for userspace which is indicated
by KVM_CAP_X86_WRITE_PROTECT_ALL_MEM

Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxx>
---
 arch/x86/kvm/x86.c       | 21 +++++++++++++++++++++
 include/uapi/linux/kvm.h |  2 ++
 2 files changed, 23 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a2cd099..ad62c44 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2723,6 +2723,17 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_X2APIC_API:
 		r = KVM_X2APIC_API_VALID_FLAGS;
 		break;
+	case KVM_CAP_X86_WRITE_PROTECT_ALL_MEM:
+		/*
+		 * do not enable it if PML is supported, this is also the
+		 * hint to tell userspace write-protect is not needed for
+		 * dirty log.
+		 */
+		if (kvm_x86_ops->slot_enable_log_dirty)
+			r = 0;
+		else
+			r = 1;
+		break;
 	default:
 		r = 0;
 		break;
@@ -4208,6 +4219,16 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = 0;
 		break;
 	}
+	case KVM_WRITE_PROTECT_ALL_MEM: {
+		if (kvm_x86_ops->slot_enable_log_dirty) {
+			r = -EINVAL;
+			break;
+		}
+
+		kvm_mmu_write_protect_all_pages(kvm, !!arg);
+		r = 0;
+		break;
+	}
 	case KVM_ENABLE_CAP: {
 		struct kvm_enable_cap cap;
 
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 577429a..7d4a395 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -895,6 +895,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_SPAPR_TCE_VFIO 142
 #define KVM_CAP_X86_GUEST_MWAIT 143
 #define KVM_CAP_ARM_USER_IRQ 144
+#define KVM_CAP_X86_WRITE_PROTECT_ALL_MEM 145
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1144,6 +1145,7 @@ struct kvm_vfio_spapr_tce {
 					struct kvm_userspace_memory_region)
 #define KVM_SET_TSS_ADDR          _IO(KVMIO,   0x47)
 #define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO,  0x48, __u64)
+#define KVM_WRITE_PROTECT_ALL_MEM _IO(KVMIO,  0x49)
 
 /* enable ucontrol for s390 */
 struct kvm_s390_ucas_mapping {
-- 
2.9.4