Userspace requests a free @domid to be assigned to itself, or
explicitly selects one by setting @any to 0. The @domid is then
used for various interdomain/unbound event purposes.
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/x86.c | 2 ++
arch/x86/kvm/xen.c | 70 +++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/xen.h | 2 ++
include/uapi/linux/kvm.h | 4 +++
5 files changed, 80 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c629fedb2e21..384247fc433d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -27,6 +27,7 @@
#include <linux/clocksource.h>
#include <linux/irqbypass.h>
#include <linux/hyperv.h>
+#include <xen/interface/xen.h>
#include <asm/apic.h>
#include <asm/pvclock-abi.h>
@@ -862,6 +863,7 @@ struct kvm_hv {
/* Xen emulation context */
struct kvm_xen {
u64 xen_hypercall;
+ domid_t domid;
gfn_t shinfo_addr;
struct shared_info *shinfo;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b1d9045d7989..cb95f7f8bed9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6986,6 +6986,7 @@ int kvm_arch_init(void *opaque)
if (hypervisor_is_type(X86_HYPER_MS_HYPERV))
set_hv_tscchange_cb(kvm_hyperv_tsc_notifier);
#endif
+ kvm_xen_init();
return 0;
@@ -6999,6 +7000,7 @@ int kvm_arch_init(void *opaque)
void kvm_arch_exit(void)
{
+ kvm_xen_exit();
#ifdef CONFIG_X86_64
if (hypervisor_is_type(X86_HYPER_MS_HYPERV))
clear_hv_tscchange_cb();
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 07066402737d..e570c9b26563 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -36,6 +36,48 @@ struct evtchnfd {
static int kvm_xen_evtchn_send(struct kvm_vcpu *vcpu, int port);
static void *xen_vcpu_info(struct kvm_vcpu *v);
+#define XEN_DOMID_MIN 1
+#define XEN_DOMID_MAX (DOMID_FIRST_RESERVED - 1)
+
+static rwlock_t domid_lock;
+static struct idr domid_to_kvm;
+
+static int kvm_xen_domid_init(struct kvm *kvm, bool any, domid_t domid)
+{
+ u16 min = XEN_DOMID_MIN, max = XEN_DOMID_MAX;
+ struct kvm_xen *xen = &kvm->arch.xen;
+ int ret;
+
+ if (!any) {
+ min = domid;
+ max = domid + 1;
+ }
+
+ write_lock_bh(&domid_lock);
+ ret = idr_alloc(&domid_to_kvm, kvm, min, max, GFP_ATOMIC);
+ write_unlock_bh(&domid_lock);
+
+ if (ret < 0)
+ return ret;
+
+ xen->domid = ret;
+ return 0;
+}
+
+int kvm_xen_free_domid(struct kvm *kvm)
+{
+ struct kvm_xen *xen = &kvm->arch.xen;
+ struct kvm *vm;
+
+ write_lock_bh(&domid_lock);
+ vm = idr_remove(&domid_to_kvm, xen->domid);
+ write_unlock_bh(&domid_lock);
+
+ synchronize_srcu(&kvm->srcu);
+
+ return vm == kvm;
+}
+
int kvm_xen_has_interrupt(struct kvm_vcpu *vcpu)
{
struct kvm_vcpu_xen *vcpu_xen = vcpu_to_xen_vcpu(vcpu);
@@ -460,6 +502,17 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
r = kvm_vm_ioctl_xen_eventfd(kvm, &xevfd);
break;
}
+ case KVM_XEN_ATTR_TYPE_DOMID: {
+ domid_t domid = (u16) data->u.dom.domid;
+ bool any = (data->u.dom.domid < 0);
+
+ /* Domain ID 0 or >= 0x7ff0 are reserved */
+ if (!any && (!domid || (domid >= XEN_DOMID_MAX)))
+ return -EINVAL;
+
+ r = kvm_xen_domid_init(kvm, any, domid);
+ break;
+ }
default:
break;
}
@@ -489,6 +542,11 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
r = 0;
break;
}
+ case KVM_XEN_ATTR_TYPE_DOMID: {
+ data->u.dom.domid = kvm->arch.xen.domid;
+ r = 0;
+ break;
+ }
default:
break;
}
@@ -909,6 +967,18 @@ void kvm_xen_destroy_vm(struct kvm *kvm)
if (xen->shinfo)
put_page(virt_to_page(xen->shinfo));
+
+ kvm_xen_free_domid(kvm);
+}
+
+void kvm_xen_init(void)
+{
+ idr_init(&domid_to_kvm);
+ rwlock_init(&domid_lock);
+}
+
+void kvm_xen_exit(void)
+{
}
static int kvm_xen_eventfd_update(struct kvm *kvm, struct idr *port_to_evt,
diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h
index f82b8b5b3345..76ef2150c650 100644
--- a/arch/x86/kvm/xen.h
+++ b/arch/x86/kvm/xen.h
@@ -39,6 +39,8 @@ void kvm_xen_destroy_vm(struct kvm *kvm);
int kvm_vm_ioctl_xen_eventfd(struct kvm *kvm, struct kvm_xen_eventfd *args);
void kvm_xen_vcpu_init(struct kvm_vcpu *vcpu);
void kvm_xen_vcpu_uninit(struct kvm_vcpu *vcpu);
+void kvm_xen_init(void);
+void kvm_xen_exit(void);
void __kvm_migrate_xen_timer(struct kvm_vcpu *vcpu);
int kvm_xen_has_pending_timer(struct kvm_vcpu *vcpu);
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 1b3ecce5f92e..3212cad732dd 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1500,6 +1500,9 @@ struct kvm_xen_hvm_attr {
__u32 padding[2];
};
} evtchn;
+ struct {
+ __s32 domid;
+ } dom;
} u;
};
@@ -1510,6 +1513,7 @@ struct kvm_xen_hvm_attr {
#define KVM_XEN_ATTR_TYPE_VCPU_RUNSTATE 0x3
/* Available with KVM_CAP_XEN_HVM_EVTCHN */
#define KVM_XEN_ATTR_TYPE_EVTCHN 0x4
+#define KVM_XEN_ATTR_TYPE_DOMID 0x5
/* Secure Encrypted Virtualization command */
enum sev_cmd_id {
--
2.11.0
