From nobody Tue Dec 30 01:33:41 2025 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 9CCDEC61D9B for ; Wed, 22 Nov 2023 12:20:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344144AbjKVMUb (ORCPT ); Wed, 22 Nov 2023 07:20:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344092AbjKVMUI (ORCPT ); Wed, 22 Nov 2023 07:20:08 -0500 Received: from mail.xenproject.org (mail.xenproject.org [104.130.215.37]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6B6B10D1; Wed, 22 Nov 2023 04:19:43 -0800 (PST) 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:To:From; bh=ssC8214qwLLmaOC7L4ZSJG6MZ31jtc2Qgti6wMfz64I=; b=6rzCyy481F50iSn6+p+qq4UgKf OedfTijLjeWT8oFeqO3sz9keZIf7+I8UNkDRRbT8QbDT/UE1ROFaw8DP9QPYZyeyNM0q2DTgn1QrI aEAqKYxc6rRFnUGWJXkqT7onyxQIvjOT6ACdh/WhENu36s0hg5rpviVWZyjgDOEeid0M=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1r5mCc-0004yp-Ls; Wed, 22 Nov 2023 12:19:34 +0000 Received: from 54-240-197-231.amazon.com ([54.240.197.231] 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 1r5mCc-0004y9-D7; Wed, 22 Nov 2023 12:19:34 +0000 From: Paul Durrant To: David Woodhouse , Paul Durrant , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v9 08/15] KVM: pfncache: allow a cache to be activated with a fixed (userspace) HVA Date: Wed, 22 Nov 2023 12:18:15 +0000 Message-Id: <20231122121822.1042-9-paul@xen.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231122121822.1042-1-paul@xen.org> References: <20231122121822.1042-1-paul@xen.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Paul Durrant Some pfncache pages may actually be overlays on guest memory that have a fixed HVA within the VMM. It's pointless to invalidate such cached mappings if the overlay is moved so allow a cache to be activated directly with the HVA to cater for such cases. A subsequent patch will make use of this facility. Signed-off-by: Paul Durrant Reviewed-by: David Woodhouse --- Cc: Sean Christopherson Cc: Paolo Bonzini Cc: David Woodhouse v9: - Pass both GPA and HVA into __kvm_gpc_refresh() rather than overloading the address paraneter and using a bool flag to indicated what it is. v8: - Re-worked to avoid messing with struct gfn_to_pfn_cache. --- include/linux/kvm_host.h | 19 ++++++++++++++++++- virt/kvm/pfncache.c | 35 +++++++++++++++++++++++++++-------- 2 files changed, 45 insertions(+), 9 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index b1dc2e5a64f3..484c587e8290 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1312,6 +1312,22 @@ void kvm_gpc_init(struct gfn_to_pfn_cache *gpc, stru= ct kvm *kvm); */ int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned lon= g len); =20 +/** + * kvm_gpc_activate_hva - prepare a cached kernel mapping and HPA for a gi= ven HVA. + * + * @gpc: struct gfn_to_pfn_cache object. + * @hva: userspace virtual address to map. + * @len: sanity check; the range being access must fit a single p= age. + * + * @return: 0 for success. + * -EINVAL for a mapping which would cross a page boundary. + * -EFAULT for an untranslatable guest physical address. + * + * The semantics of this function are the same as those of kvm_gpc_activat= e(). It + * merely bypasses a layer of address translation. + */ +int kvm_gpc_activate_hva(struct gfn_to_pfn_cache *gpc, unsigned long hva, = unsigned long len); + /** * kvm_gpc_check - check validity of a gfn_to_pfn_cache. * @@ -1365,7 +1381,8 @@ void kvm_gpc_deactivate(struct gfn_to_pfn_cache *gpc); */ static inline void kvm_gpc_mark_dirty(struct gfn_to_pfn_cache *gpc) { - mark_page_dirty_in_slot(gpc->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT); + if (gpc->gpa !=3D KVM_XEN_INVALID_GPA) + mark_page_dirty_in_slot(gpc->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT); } =20 void kvm_sigset_activate(struct kvm_vcpu *vcpu); diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 97eec8ee3449..c2a2d1e145b6 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -209,11 +209,13 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_c= ache *gpc) return -EFAULT; } =20 -static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, +static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsi= gned long uhva, unsigned long len) { struct kvm_memslots *slots =3D kvm_memslots(gpc->kvm); - unsigned long page_offset =3D offset_in_page(gpa); + unsigned long page_offset =3D (gpa !=3D KVM_XEN_INVALID_GPA) ? + offset_in_page(gpa) : + offset_in_page(uhva); bool unmap_old =3D false; unsigned long old_uhva; kvm_pfn_t old_pfn; @@ -246,9 +248,15 @@ static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *= gpc, gpa_t gpa, old_khva =3D (void *)PAGE_ALIGN_DOWN((uintptr_t)gpc->khva); old_uhva =3D PAGE_ALIGN_DOWN(gpc->uhva); =20 - /* Refresh the userspace HVA if necessary */ - if (gpc->gpa !=3D gpa || gpc->generation !=3D slots->generation || - kvm_is_error_hva(gpc->uhva)) { + if (gpa =3D=3D KVM_XEN_INVALID_GPA) { + gpc->gpa =3D KVM_XEN_INVALID_GPA; + gpc->uhva =3D PAGE_ALIGN_DOWN(uhva); + + if (gpc->uhva !=3D old_uhva) + hva_change =3D true; + } else if (gpc->gpa !=3D gpa || + gpc->generation !=3D slots->generation || + kvm_is_error_hva(gpc->uhva)) { gfn_t gfn =3D gpa_to_gfn(gpa); =20 gpc->gpa =3D gpa; @@ -319,7 +327,7 @@ static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *g= pc, gpa_t gpa, =20 int kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, unsigned long len) { - return __kvm_gpc_refresh(gpc, gpc->gpa, len); + return __kvm_gpc_refresh(gpc, gpc->gpa, gpc->uhva, len); } =20 void kvm_gpc_init(struct gfn_to_pfn_cache *gpc, struct kvm *kvm) @@ -332,7 +340,8 @@ void kvm_gpc_init(struct gfn_to_pfn_cache *gpc, struct = kvm *kvm) gpc->uhva =3D KVM_HVA_ERR_BAD; } =20 -int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned lon= g len) +static int __kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, uns= igned long uhva, + unsigned long len) { struct kvm *kvm =3D gpc->kvm; =20 @@ -353,7 +362,17 @@ int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa= _t gpa, unsigned long len) gpc->active =3D true; write_unlock_irq(&gpc->lock); } - return __kvm_gpc_refresh(gpc, gpa, len); + return __kvm_gpc_refresh(gpc, gpa, uhva, len); +} + +int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned lon= g len) +{ + return __kvm_gpc_activate(gpc, gpa, KVM_HVA_ERR_BAD, len); +} + +int kvm_gpc_activate_hva(struct gfn_to_pfn_cache *gpc, unsigned long uhva,= unsigned long len) +{ + return __kvm_gpc_activate(gpc, KVM_XEN_INVALID_GPA, uhva, len); } =20 void kvm_gpc_deactivate(struct gfn_to_pfn_cache *gpc) --=20 2.39.2