KVM: x86/xen: Add KVM_XEN_INVALID_GPA and KVM_XEN_INVALID_GFN to uapi

These are (uint64_t)-1 magic values are a userspace ABI, allowing the shared info pages and other enlightenments to be disabled. This isn't a Xen ABI because Xen doesn't let the guest turn these off except with the full SHUTDOWN_soft_reset mechanism. Under KVM, the userspace VMM is expected to handle soft reset, and tear down the kernel parts of the enlightenments accordingly. Suggested-by: Sean Christopherson <[email protected]> Signed-off-by: David Woodhouse <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
torvalds · Dec 27, 2022 · b0305c1 · b0305c1
1 parent 1c14faa
commit b0305c1
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Showing 2 changed files with 10 additions and 7 deletions.
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
@@ -41,7 +41,7 @@ static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
  int ret = 0;
  int idx = srcu_read_lock(&kvm->srcu);
 
- if (gfn == GPA_INVALID) {
+ if (gfn == KVM_XEN_INVALID_GFN) {
  kvm_gpc_deactivate(gpc);
  goto out;
  }
@@ -659,7 +659,7 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
  if (kvm->arch.xen.shinfo_cache.active)
  data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa);
  else
- data->u.shared_info.gfn = GPA_INVALID;
+ data->u.shared_info.gfn = KVM_XEN_INVALID_GFN;
  r = 0;
  break;
 
@@ -705,7 +705,7 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
  BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
  offsetof(struct compat_vcpu_info, time));
 
- if (data->u.gpa == GPA_INVALID) {
+ if (data->u.gpa == KVM_XEN_INVALID_GPA) {
  kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
  r = 0;
  break;
@@ -719,7 +719,7 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
  break;
 
  case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
- if (data->u.gpa == GPA_INVALID) {
+ if (data->u.gpa == KVM_XEN_INVALID_GPA) {
  kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
  r = 0;
  break;
@@ -739,7 +739,7 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
  r = -EOPNOTSUPP;
  break;
  }
- if (data->u.gpa == GPA_INVALID) {
+ if (data->u.gpa == KVM_XEN_INVALID_GPA) {
  r = 0;
  deactivate_out:
  kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
@@ -937,15 +937,15 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
  if (vcpu->arch.xen.vcpu_info_cache.active)
  data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
  else
- data->u.gpa = GPA_INVALID;
+ data->u.gpa = KVM_XEN_INVALID_GPA;
  r = 0;
  break;
 
  case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
  if (vcpu->arch.xen.vcpu_time_info_cache.active)
  data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
  else
- data->u.gpa = GPA_INVALID;
+ data->u.gpa = KVM_XEN_INVALID_GPA;
  r = 0;
  break;
 

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
@@ -1767,6 +1767,7 @@ struct kvm_xen_hvm_attr {
  __u8 runstate_update_flag;
  struct {
  __u64 gfn;
+#define KVM_XEN_INVALID_GFN ((__u64)-1)
  } shared_info;
  struct {
  __u32 send_port;
@@ -1798,6 +1799,7 @@ struct kvm_xen_hvm_attr {
  } u;
 };
 
+
 /* Available with KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO */
 #define KVM_XEN_ATTR_TYPE_LONG_MODE 0x0
 #define KVM_XEN_ATTR_TYPE_SHARED_INFO 0x1
@@ -1823,6 +1825,7 @@ struct kvm_xen_vcpu_attr {
  __u16 pad[3];
  union {
  __u64 gpa;
+#define KVM_XEN_INVALID_GPA ((__u64)-1)
  __u64 pad[8];
  struct {
  __u64 state;