On 12/14/20 8:39 AM, David Woodhouse wrote:
> From: Joao Martins <joao.m.martins@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
> ---
> arch/x86/include/asm/kvm_host.h | 2 ++
> arch/x86/kvm/x86.c | 2 ++
> arch/x86/kvm/xen.c | 26 ++++++++++++++++++++++++++
> include/uapi/linux/kvm.h | 1 +
> 4 files changed, 31 insertions(+)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 56c00a9441a3..b7dfcb4de92a 100644
> --- 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 cbdc05bb53bd..2234fdf49d82 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2729,6 +2729,8 @@ 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 d2055b60fdc1..1cca46effec8 100644
> --- 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;
Same comment as shared_info: we probably don't need vcpu_time_info_set if we piggyback
on the gfn_to_hva cache setting its @gpa field.
> + 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 87d150992f48..f60c5c61761c 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1599,6 +1599,7 @@ 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 {
>
