From patchwork Thu Sep 14 08:49:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 13384884 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06675EDE99D for ; Thu, 14 Sep 2023 09:07:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237148AbjINJHs (ORCPT ); Thu, 14 Sep 2023 05:07:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237147AbjINJHb (ORCPT ); Thu, 14 Sep 2023 05:07:31 -0400 Received: from mail.xenproject.org (mail.xenproject.org [104.130.215.37]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48DB61FD8; Thu, 14 Sep 2023 02:07:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=oynQFx0otpLWpBva3wvVisOGWIw7kSbKH068QhWuZHg=; b=0SyaZmIYZEWLIMJhI4fFFRNZwP thgb8VZt7BuPHIFH+3CZSAd/SRB1oDDjz+lD1pYbFLhBUzm+MwXm7XtRa1QG9KvvFtLqJfzDkk02q Jrsi1U5rfTL+D5URpzu5ZxGQlt4eNYmzI0o0jeqnRwxR4Izz0gDQXZqNui0ieFf8qZPg=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qgi3L-0001kP-Ns; Thu, 14 Sep 2023 08:50:23 +0000 Received: from ec2-63-33-11-17.eu-west-1.compute.amazonaws.com ([63.33.11.17] helo=REM-PW02S00X.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qgi3L-0002T9-GN; Thu, 14 Sep 2023 08:50:23 +0000 From: Paul Durrant To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Paul Durrant , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , David Woodhouse , x86@kernel.org Subject: [PATCH 6/8] KVM: xen: allow shared_info to be mapped by fixed HVA Date: Thu, 14 Sep 2023 08:49:44 +0000 Message-Id: <20230914084946.200043-7-paul@xen.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230914084946.200043-1-paul@xen.org> References: <20230914084946.200043-1-paul@xen.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Paul Durrant The shared_info page is not guest memory as such. It is a dedicated page allocated by the VMM and overlaid onto guest memory in a GFN chosen by the guest. The guest may even request that shared_info be moved from one GFN to another, but the HVA is never going to change. Thus it makes much more sense to map the shared_info page in kernel once using this fixed HVA. Hence add a new KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA attribute type for this purpose and a KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag to advertize its availability. Signed-off-by: Paul Durrant Reviewed-by: David Woodhouse --- Cc: Sean Christopherson Cc: Paolo Bonzini Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: David Woodhouse Cc: x86@kernel.org --- arch/x86/kvm/x86.c | 3 ++- arch/x86/kvm/xen.c | 28 ++++++++++++++++++++++------ include/uapi/linux/kvm.h | 6 +++++- 3 files changed, 29 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d669a8801265..0df06f47801c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4531,7 +4531,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL | KVM_XEN_HVM_CONFIG_SHARED_INFO | KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL | - KVM_XEN_HVM_CONFIG_EVTCHN_SEND; + KVM_XEN_HVM_CONFIG_EVTCHN_SEND | + KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA; if (sched_info_on()) r |= KVM_XEN_HVM_CONFIG_RUNSTATE | KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG; diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 8e6fdcd7bb6e..1abb4547642a 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -34,24 +34,27 @@ static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r); DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ); -static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn) +static int kvm_xen_shared_info_init(struct kvm *kvm, u64 addr, bool addr_is_gfn) { struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache; struct pvclock_wall_clock *wc; - gpa_t gpa = gfn_to_gpa(gfn); u32 *wc_sec_hi; u32 wc_version; u64 wall_nsec; int ret = 0; int idx = srcu_read_lock(&kvm->srcu); - if (gfn == KVM_XEN_INVALID_GFN) { + if ((addr_is_gfn && addr == KVM_XEN_INVALID_GFN) || + (!addr_is_gfn && addr == 0)) { kvm_gpc_deactivate(gpc); goto out; } do { - ret = kvm_gpc_activate(gpc, gpa, PAGE_SIZE); + if (addr_is_gfn) + ret = kvm_gpc_activate(gpc, gfn_to_gpa(addr), PAGE_SIZE); + else + ret = kvm_gpc_activate_hva(gpc, addr, PAGE_SIZE); if (ret) goto out; @@ -604,7 +607,6 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) { int r = -ENOENT; - switch (data->type) { case KVM_XEN_ATTR_TYPE_LONG_MODE: if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) { @@ -619,7 +621,13 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) case KVM_XEN_ATTR_TYPE_SHARED_INFO: mutex_lock(&kvm->arch.xen.xen_lock); - r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn); + r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn, true); + mutex_unlock(&kvm->arch.xen.xen_lock); + break; + + case KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA: + mutex_lock(&kvm->arch.xen.xen_lock); + r = kvm_xen_shared_info_init(kvm, data->u.shared_info.hva, false); mutex_unlock(&kvm->arch.xen.xen_lock); break; @@ -684,6 +692,14 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) r = 0; break; + case KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA: + if (kvm->arch.xen.shinfo_cache.active) + data->u.shared_info.hva = kvm_gpc_hva(&kvm->arch.xen.shinfo_cache); + else + data->u.shared_info.hva = 0; + r = 0; + break; + case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR: data->u.vector = kvm->arch.xen.upcall_vector; r = 0; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index f089ab290978..d3f371bafad8 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1282,6 +1282,7 @@ struct kvm_x86_mce { #define KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL (1 << 4) #define KVM_XEN_HVM_CONFIG_EVTCHN_SEND (1 << 5) #define KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG (1 << 6) +#define KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA (1 << 7) struct kvm_xen_hvm_config { __u32 flags; @@ -1786,9 +1787,10 @@ struct kvm_xen_hvm_attr { __u8 long_mode; __u8 vector; __u8 runstate_update_flag; - struct { + union { __u64 gfn; #define KVM_XEN_INVALID_GFN ((__u64)-1) + __u64 hva; } shared_info; struct { __u32 send_port; @@ -1830,6 +1832,8 @@ struct kvm_xen_hvm_attr { #define KVM_XEN_ATTR_TYPE_XEN_VERSION 0x4 /* Available with KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG */ #define KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG 0x5 +/* Available with KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA */ +#define KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA 0x6 /* Per-vCPU Xen attributes */ #define KVM_XEN_VCPU_GET_ATTR _IOWR(KVMIO, 0xca, struct kvm_xen_vcpu_attr)