From b0305c1e0e27ad91187bc6d5ac3d502799faf239 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Mon, 26 Dec 2022 12:03:19 +0000 Subject: [PATCH] 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 Signed-off-by: David Woodhouse Message-Id: <20221226120320.1125390-5-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/xen.c | 14 +++++++------- include/uapi/linux/kvm.h | 3 +++ 2 files changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index bddbe5ac5cfa..b178f40bd863 100644 --- 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); @@ -937,7 +937,7 @@ 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; @@ -945,7 +945,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) 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 index 20522d4ba1e0..55155e262646 100644 --- 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; -- 2.39.5