From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0390CC433EF for ; Wed, 13 Oct 2021 15:59:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8E3F60EE9 for ; Wed, 13 Oct 2021 15:59:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237211AbhJMQB0 (ORCPT ); Wed, 13 Oct 2021 12:01:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236277AbhJMQBI (ORCPT ); Wed, 13 Oct 2021 12:01:08 -0400 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9F24C061749 for ; Wed, 13 Oct 2021 08:59:04 -0700 (PDT) Received: by mail-qv1-xf49.google.com with SMTP id kk3-20020a056214508300b00382d8d1bd71so2979269qvb.7 for ; Wed, 13 Oct 2021 08:59:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=DEoxdh+qQqNfn4kriXOPtuGm5/KezrtRJAuAEOvIIEc=; b=TpLWDDRB66gNFtTO9H4DRYs+65J/g5K+vn3S4IswImh0cKDwKxr4tBSjZcRccVl/Gl PA7nAXYwmNvaJhrKw46Ts3VNmjOrJZAny7BGVWCNErEuHLrCRinaJt33ySp3tdu1rhlU ObF8iMNmln/oDydOezVDr5M8tvVtysJpT8v+dFboU9XBwY12v9a9YJdoISKQDzlPyc89 gwxqYq45K+oRmNXwFvSb/RgfedaC9VADqHJA3tsa8lwe9+sahvN4PIU9zbtzmjuqi1TS TY2B5+x2nY3sIMBjjwqLbn3F5AEhqAsehabz6sua9uKu7eipWBEh68yQaYKn6biu+OzM jw3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=DEoxdh+qQqNfn4kriXOPtuGm5/KezrtRJAuAEOvIIEc=; b=rv6wfSB47FchnkElzmDOGIg/6PMnPuVJ1Z//gsZzbIHplFGAo1wxFvarIh6pbbE+89 FZlmoh8ChThvNghHTuDrFA+D9NZ3cnCUz9ZC1kpbp78pO8rU4kzyP4lD+l05HhDDaVFJ KPDYO9i4/K4csqlCMS5R64HGRnG+hq7kGwTNtL9jO8TrvRl6jJ7DRLn5KHE/NBrFwic2 ZkXGCvqJODLJQ5oVLVekNTPqh5n5X39sGezh0/mAmbbbPS4SDnm1kTRmoHo9+5I/oeNX BVXHbmJkNgniue383SazuWBq4x/UYkDdGapgataUKPNoILDj+p82iGW8hts5b2PEt3BA UfEg== X-Gm-Message-State: AOAM532RcL2MlJuXtUg6ifXpU1D+aD+lKNLsDwxFXbZCVv/ZdFnFqhsS OfmOmM+ZBhZtOlBIF5ICeHIST8eZe5Vp X-Google-Smtp-Source: ABdhPJxxY5hYqLzNoNmIsVUGeAsrdYoGroAg6GyRP+fKCKJAdv6jBH4kuWvly/Nv7EL03M4qWkxiLE/AW3NG X-Received: from luke.lon.corp.google.com ([2a00:79e0:d:210:65b5:73d3:1558:b9ae]) (user=qperret job=sendgmr) by 2002:ac8:5385:: with SMTP id x5mr73629qtp.105.1634140744121; Wed, 13 Oct 2021 08:59:04 -0700 (PDT) Date: Wed, 13 Oct 2021 16:58:28 +0100 In-Reply-To: <20211013155831.943476-1-qperret@google.com> Message-Id: <20211013155831.943476-14-qperret@google.com> Mime-Version: 1.0 References: <20211013155831.943476-1-qperret@google.com> X-Mailer: git-send-email 2.33.0.882.g93a45727a2-goog Subject: [PATCH 13/16] KVM: arm64: Move double-sharing logic into hyp-specific function From: Quentin Perret To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , Fuad Tabba , David Brazdil Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Will Deacon Strictly speaking, double-sharing a page is an invalid transition and should be rejected, however we allow this in order to simplify the book-keeping when KVM metadata (such as vcpu structures) co-exists in the same page. Given that double-sharing is only required for pages shared with the hypervisor by the host, move the handling into a hyp-specific function to check incoming shares, therefore preventing double-sharing outside of this particular transition. Signed-off-by: Will Deacon Signed-off-by: Quentin Perret --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 57 +++++++++++++++++++-------- 1 file changed, 41 insertions(+), 16 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 909e60f71b06..3378117d010c 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -536,6 +536,33 @@ static int ack_share(struct pkvm_page_share_ack *ack, } } +static int hyp_check_incoming_share(struct pkvm_page_req *req, + struct pkvm_page_share_ack *ack, + enum pkvm_component_id initiator, + enum kvm_pgtable_prot prot) +{ + /* + * We allow the host to share the same page twice, but that means we + * have to check that the states really do match exactly. + */ + if (initiator != PKVM_ID_HOST) + return -EPERM; + + if (req->initiator.state != PKVM_PAGE_SHARED_OWNED) + return -EPERM; + + if (ack->completer.state != PKVM_PAGE_SHARED_BORROWED) + return -EPERM; + + if (ack->completer.phys != req->phys) + return -EPERM; + + if (ack->completer.prot != prot) + return -EPERM; + + return 0; +} + /* * Check that the page states in the initiator and the completer are compatible * for the requested page-sharing operation to go ahead. @@ -544,6 +571,8 @@ static int check_share(struct pkvm_page_req *req, struct pkvm_page_share_ack *ack, struct pkvm_mem_share *share) { + struct pkvm_mem_transition *tx = &share->tx; + if (!addr_is_memory(req->phys)) return -EINVAL; @@ -552,25 +581,22 @@ static int check_share(struct pkvm_page_req *req, return 0; } - if (req->initiator.state != PKVM_PAGE_SHARED_OWNED) - return -EPERM; - - if (ack->completer.state != PKVM_PAGE_SHARED_BORROWED) - return -EPERM; - - if (ack->completer.phys != req->phys) - return -EPERM; - - if (ack->completer.prot != share->prot) + switch (tx->completer.id) { + case PKVM_ID_HYP: + return hyp_check_incoming_share(req, ack, tx->initiator.id, + share->prot); + default: return -EPERM; - - return 0; + } } static int host_initiate_share(struct pkvm_page_req *req) { enum kvm_pgtable_prot prot; + if (req->initiator.state == PKVM_PAGE_SHARED_OWNED) + return 0; + prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED); return host_stage2_idmap_locked(req->initiator.addr, PAGE_SIZE, prot); } @@ -595,6 +621,9 @@ static int hyp_complete_share(struct pkvm_page_req *req, void *start = (void *)req->completer.addr, *end = start + PAGE_SIZE; enum kvm_pgtable_prot prot; + if (req->initiator.state == PKVM_PAGE_SHARED_OWNED) + return 0; + prot = pkvm_mkstate(perms, PKVM_PAGE_SHARED_BORROWED); return pkvm_create_mappings_locked(start, end, prot); } @@ -653,10 +682,6 @@ static int do_share(struct pkvm_mem_share *share) if (ret) break; - /* Allow double-sharing by skipping over the page */ - if (req.initiator.state == PKVM_PAGE_SHARED_OWNED) - continue; - ret = initiate_share(&req, share); if (ret) break; -- 2.33.0.882.g93a45727a2-goog