KVM: x86: implement KVM_CAP_SET_GUEST_DEBUG2

Store the supported bits into KVM_GUESTDBG_VALID_MASK
macro, similar to how arm does this.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210401135451.1004564-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -221,6 +221,15 @@ enum x86_intercept_stage;
 #define DR7_FIXED_1	0x00000400
 #define DR7_VOLATILE	0xffff2bff
 
+#define KVM_GUESTDBG_VALID_MASK \
+	(KVM_GUESTDBG_ENABLE | \
+	KVM_GUESTDBG_SINGLESTEP | \
+	KVM_GUESTDBG_USE_HW_BP | \
+	KVM_GUESTDBG_USE_SW_BP | \
+	KVM_GUESTDBG_INJECT_BP | \
+	KVM_GUESTDBG_INJECT_DB)
+
+
 #define PFERR_PRESENT_BIT 0
 #define PFERR_WRITE_BIT 1
 #define PFERR_USER_BIT 2

arch/x86/kvm/x86.c

@@ -3804,6 +3804,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ENFORCE_PV_FEATURE_CPUID:
 		r = 1;
 		break;
+	case KVM_CAP_SET_GUEST_DEBUG2:
+		return KVM_GUESTDBG_VALID_MASK;
 #ifdef CONFIG_KVM_XEN
 	case KVM_CAP_XEN_HVM:
 		r = KVM_XEN_HVM_CONFIG_HYPERCALL_MSR |