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 eabd0bf0035f5e61d4f3ea8a2464f49b840b330e..bd8c39d08c65ec97c3b1260edc6a4ac9f30c9f4e 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 228dd5ab9a813a4bb1e28ba4bd5822afb801a6a0..b81d8a0c2154599b210d2ce840c58bb2be69849d 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 6a5ff37874f4e7fcaee6980c97334bed1294b849..32ad196d18344100c3e3397d65bbc75a76f83714 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1605,6 +1605,7 @@ 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 {