From patchwork Thu Feb 10 00:27:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 12741124 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 D78D1C433EF for ; Thu, 10 Feb 2022 01:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232972AbiBJBcB (ORCPT ); Wed, 9 Feb 2022 20:32:01 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:39104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232735AbiBJBbv (ORCPT ); Wed, 9 Feb 2022 20:31:51 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32685F47 for ; Wed, 9 Feb 2022 17:31:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=JG1kCAvlUbp2aaGqscsx7yUF7CXhQvJDhw2H3fyYAAQ=; b=c/peA/xEgqpvnKbFzSCx3g/NNV C7mvSZCDUR7oxuyfNXzZ1e2hMM/3nBgVglmUxbTB3Wu4kj3b2BC3A6lmJeeNf/Bjnl28yW5qJcclf RBFr4v/gf3gJrLlBqtPLYP1qavlgvmm35X4zzrZtR7vawYM7EULLSTkHy4FRqT9MPPJ3z/L7FHUZl +LSuTOEc4Z1N5uTlNXENd+fc5K9oh+fgQuo9nqX0FcyP9qiQnt+bUQg1SdA4wHhPj7LshcfKROjqP BQq2DbulXplRI6HYU7YJjwBDFmmUGncPKSsxIiSCxUCDvI3EhkkAgE08CFKWeBmLNKFYTIAbDUqKm J/TffRfQ==; Received: from i7.infradead.org ([2001:8b0:10b:1:21e:67ff:fecb:7a92]) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nHxIy-008xlB-P3; Thu, 10 Feb 2022 00:27:24 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nHxIy-0019Dc-7Y; Thu, 10 Feb 2022 00:27:24 +0000 From: David Woodhouse To: kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Joao Martins , Boris Ostrovsky , Metin Kaya , Paul Durrant Subject: [PATCH v0 12/15] KVM: x86/xen: Kernel acceleration for XENVER_version Date: Thu, 10 Feb 2022 00:27:18 +0000 Message-Id: <20220210002721.273608-13-dwmw2@infradead.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20220210002721.273608-1-dwmw2@infradead.org> References: <20220210002721.273608-1-dwmw2@infradead.org> MIME-Version: 1.0 Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: David Woodhouse Turns out this is a fast path for PV guests because they use it to trigger the event channel upcall. So letting it bounce all the way up to userspace is not great. Signed-off-by: David Woodhouse --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/xen.c | 18 ++++++++++++++++++ include/uapi/linux/kvm.h | 3 ++- 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ddfdc8cc8e60..1c064c2ec937 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1021,6 +1021,7 @@ struct msr_bitmap_range { /* Xen emulation context */ struct kvm_xen { + u32 xen_version; bool long_mode; u8 upcall_vector; struct gfn_to_pfn_cache shinfo_cache; diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index c042c7d6ee02..735fccd44488 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -479,6 +480,12 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) r = kvm_xen_setattr_evtchn(kvm, data); break; + case KVM_XEN_ATTR_TYPE_XEN_VERSION: + mutex_lock(&kvm->lock); + kvm->arch.xen.xen_version = data->u.xen_version; + mutex_unlock(&kvm->lock); + break; + default: break; } @@ -511,6 +518,11 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) r = 0; break; + case KVM_XEN_ATTR_TYPE_XEN_VERSION: + data->u.xen_version = kvm->arch.xen.xen_version; + r = 0; + break; + default: break; } @@ -1049,6 +1061,12 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu) params[3], params[4], params[5]); switch (input) { + case __HYPERVISOR_xen_version: + if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) { + r = vcpu->kvm->arch.xen.xen_version; + handled = true; + } + break; case __HYPERVISOR_event_channel_op: if (params[0] == EVTCHNOP_send) handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r); diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index f485b536112f..243917851e0d 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1703,7 +1703,7 @@ struct kvm_xen_hvm_attr { __u32 padding[4]; } deliver; } evtchn; - + __u32 xen_version; __u64 pad[8]; } u; }; @@ -1714,6 +1714,7 @@ struct kvm_xen_hvm_attr { #define KVM_XEN_ATTR_TYPE_UPCALL_VECTOR 0x2 /* Available with KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND */ #define KVM_XEN_ATTR_TYPE_EVTCHN 0x3 +#define KVM_XEN_ATTR_TYPE_XEN_VERSION 0x4 /* Per-vCPU Xen attributes */ #define KVM_XEN_VCPU_GET_ATTR _IOWR(KVMIO, 0xca, struct kvm_xen_vcpu_attr)