KVM: x86/xen: register vcpu time info region

Allow the Xen emulated guest the ability to register secondary
vcpu time information. On Xen guests this is used in order to be
mapped to userspace and hence allow vdso gettimeofday to work.

In doing so, move kvm_xen_set_pvclock_page() logic to
kvm_xen_update_vcpu_time() and have the former a top-level
function which updates primary vcpu time info (in struct vcpu_info)
and secondary one.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 421d082d772d01462d54e02fc8c09e4fceec025b..cd65bd43fc5fed8d4065f85c70edf9ff9bf07ddf 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -524,7 +524,9 @@ struct kvm_vcpu_hv {
 struct kvm_vcpu_xen {
        u64 hypercall_rip;
        bool vcpu_info_set;
+       bool vcpu_time_info_set;
        struct gfn_to_hva_cache vcpu_info_cache;
+       struct gfn_to_hva_cache vcpu_time_info_cache;
 };
 
 struct kvm_vcpu_arch {

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index af4490c20d6340d3df0ea90aeeacf06bef9fe7a9..1cf503d559ebfb3974443eed0ade4bae388429d7 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2735,6 +2735,8 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
        if (vcpu->xen.vcpu_info_set)
                kvm_setup_pvclock_page(v, &vcpu->xen.vcpu_info_cache,
                                       offsetof(struct compat_vcpu_info, time));
+       if (vcpu->xen.vcpu_time_info_set)
+               kvm_setup_pvclock_page(v, &vcpu->xen.vcpu_time_info_cache, 0);
        if (v == kvm_get_vcpu(v->kvm, 0))
                kvm_hv_setup_tsc_page(v->kvm, &vcpu->hv_clock);
        return 0;

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index d2055b60fdc1414f267a66571c45189d552eaec6..1cca46effec850d72993a4d709db338b9f51702f 100644 (file)
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -95,6 +95,21 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
                break;
 
+       case KVM_XEN_ATTR_TYPE_VCPU_TIME_INFO:
+               v = kvm_get_vcpu_by_id(kvm, data->u.vcpu_attr.vcpu_id);
+               if (!v)
+                       return -EINVAL;
+
+               r = kvm_gfn_to_hva_cache_init(kvm, &v->arch.xen.vcpu_time_info_cache,
+                                             data->u.vcpu_attr.gpa,
+                                             sizeof(struct pvclock_vcpu_time_info));
+               if (r)
+                       return r;
+
+               v->arch.xen.vcpu_time_info_set = true;
+               kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
+               break;
+
        default:
                break;
        }
@@ -131,6 +146,17 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
                }
                break;
 
+       case KVM_XEN_ATTR_TYPE_VCPU_TIME_INFO:
+               v = kvm_get_vcpu_by_id(kvm, data->u.vcpu_attr.vcpu_id);
+               if (!v)
+                       return -EINVAL;
+
+               if (v->arch.xen.vcpu_time_info_set) {
+                       data->u.vcpu_attr.gpa = v->arch.xen.vcpu_time_info_cache.gpa;
+                       r = 0;
+               }
+               break;
+
        default:
                break;
        }

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 5ab0063d109a442456df30087c10c7ebfdbe0050..6e91c004ae68614f0055a5e7332244a4d942c025 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1607,6 +1607,7 @@ struct kvm_xen_hvm_attr {
 #define KVM_XEN_ATTR_TYPE_LONG_MODE            0x0
 #define KVM_XEN_ATTR_TYPE_SHARED_INFO          0x1
 #define KVM_XEN_ATTR_TYPE_VCPU_INFO            0x2
+#define KVM_XEN_ATTR_TYPE_VCPU_TIME_INFO       0x3
 
 /* Secure Encrypted Virtualization command */
 enum sev_cmd_id {