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 0E5EFC433F5 for ; Tue, 19 Oct 2021 12:13:44 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id B27C96135E for ; Tue, 19 Oct 2021 12:13:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B27C96135E Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 662CD4B1A3; Tue, 19 Oct 2021 08:13:43 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@google.com Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id uVrWbBaPwCRl; Tue, 19 Oct 2021 08:13:42 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 3E8ED4B0F7; Tue, 19 Oct 2021 08:13:42 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2710F4B093 for ; Tue, 19 Oct 2021 08:13:40 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id FKB4uOmIvNyH for ; Tue, 19 Oct 2021 08:13:39 -0400 (EDT) Received: from mail-lj1-f202.google.com (mail-lj1-f202.google.com [209.85.208.202]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 78DC74B0EF for ; Tue, 19 Oct 2021 08:13:38 -0400 (EDT) Received: by mail-lj1-f202.google.com with SMTP id n11-20020a2ebd0b000000b001f9ebdc2b7aso821945ljq.6 for ; Tue, 19 Oct 2021 05:13:38 -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=ISeivE4VJePhwCDFvsBtzOVIerKBvyMpPq/U4suJ8Dg=; b=pMTyZ0Vbl+u7Dlf64iUAHAL8iII5oExKlGMnTMHZaH1N3KOh6pszIEURsP71VOA8zm YmAfLbs73BpmIWiQFsAwuQdZch7d1aBX0VE1dqPVlo4MR+Iv3SEIvK1dzqA44YUBqokQ 3BWhGEojgqF2KRv1G62YRc39Vn8Nnjta2ATq8LApIpEt7DGix0abtEW9pGr56bx76kdj 22z6U+fFymB5GMOz4WZX6L7B8vnwJ+yGDZM1gxOHNZEdOyXICg/04hJWqSYDUUhm5VGZ 8XPgn1dhN12ntFAgc27i+8EKZxW4j4Rv26/Vjwmr2QvI0pNoKwfj6Pef3gBLMRK7blQh duHQ== 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=ISeivE4VJePhwCDFvsBtzOVIerKBvyMpPq/U4suJ8Dg=; b=bl8ztmkjLlxMeDljdLVxx4a62wiHv/jh5hVLdq/jS6MOjeaqkbsOOu44a/V3TS+nst FQRpZ6peFN6BzM5ZH+yesTuyOmnEXzWbWZyuHcvZm/e7Z3t2Pmk8prkjgaTaPRsiIuWD iriMGCdVYWrUUOZQquJjavEFZzJL8G1GF0xDf5n0gR1nhLTe0sQndxEj4BTc2RDlNE3/ wYuzjmlqplnJZRuB2yKqprbDOPD8pSy4muEsZyOQWYSLqWtQ5pi/rvic5gsNkLF8Fb8l IXsdo0ckwBWYmm40QRkK1BBvymmVHhGgYwv95i6Y/Y3Q3kCz00S8EMdQcLIs45zKa6Rj pPCA== X-Gm-Message-State: AOAM533uAw4kFTT+IT6dHMy+STpFN6ZIgelGSltlFjoWLR5/iBNtkF39 QEvOd9lFlxofkuVZmgmwCDNdIgHQWgVv X-Google-Smtp-Source: ABdhPJwgKkmhxiB5XvxU66pG49kdREnEBCBJUkS8jWIoTxJjPaFPdF/auvzHlo/liyhgODAIlIOug/KJN2Yd X-Received: from luke.lon.corp.google.com ([2a00:79e0:d:210:59ca:401f:83a8:de6d]) (user=qperret job=sendgmr) by 2002:a2e:7816:: with SMTP id t22mr6884979ljc.133.1634645617143; Tue, 19 Oct 2021 05:13:37 -0700 (PDT) Date: Tue, 19 Oct 2021 13:13:02 +0100 In-Reply-To: <20211019121304.2732332-1-qperret@google.com> Message-Id: <20211019121304.2732332-14-qperret@google.com> Mime-Version: 1.0 References: <20211019121304.2732332-1-qperret@google.com> X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog Subject: [PATCH v2 13/15] KVM: arm64: Implement do_unshare() helper for unsharing memory From: Quentin Perret To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , Fuad Tabba , David Brazdil , Andrew Walbran Cc: kernel-team@android.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu From: Will Deacon Tearing down a previously shared memory region results in the borrower losing access to the underlying pages and returning them to the "owned" state in the owner. Implement a do_unshare() helper, along the same lines as do_share(), to provide this functionality for the host-to-hyp case. Signed-off-by: Will Deacon Signed-off-by: Quentin Perret --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 115 ++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index ab1732c38b3b..205616c9f107 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -474,6 +474,16 @@ static int host_request_owned_transition(u64 *completer_addr, return __host_check_page_state_range(addr, size, PKVM_PAGE_OWNED); } +static int host_request_unshare(u64 *completer_addr, + const struct pkvm_mem_transition *tx) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + u64 addr = tx->initiator.addr; + + *completer_addr = tx->initiator.host.completer_addr; + return __host_check_page_state_range(addr, size, PKVM_PAGE_SHARED_OWNED); +} + static int host_initiate_share(u64 *completer_addr, const struct pkvm_mem_transition *tx) { @@ -484,6 +494,16 @@ static int host_initiate_share(u64 *completer_addr, return __host_set_page_state_range(addr, size, PKVM_PAGE_SHARED_OWNED); } +static int host_initiate_unshare(u64 *completer_addr, + const struct pkvm_mem_transition *tx) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + u64 addr = tx->initiator.addr; + + *completer_addr = tx->initiator.host.completer_addr; + return __host_set_page_state_range(addr, size, PKVM_PAGE_OWNED); +} + static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte) { if (!kvm_pte_valid(pte)) @@ -524,6 +544,17 @@ static int hyp_ack_share(u64 addr, const struct pkvm_mem_transition *tx, return __hyp_check_page_state_range(addr, size, PKVM_NOPAGE); } +static int hyp_ack_unshare(u64 addr, const struct pkvm_mem_transition *tx) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + + if (__hyp_ack_skip_pgtable_check(tx)) + return 0; + + return __hyp_check_page_state_range(addr, size, + PKVM_PAGE_SHARED_BORROWED); +} + static int hyp_complete_share(u64 addr, const struct pkvm_mem_transition *tx, enum kvm_pgtable_prot perms) { @@ -534,6 +565,14 @@ static int hyp_complete_share(u64 addr, const struct pkvm_mem_transition *tx, return pkvm_create_mappings_locked(start, end, prot); } +static int hyp_complete_unshare(u64 addr, const struct pkvm_mem_transition *tx) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + int ret = kvm_pgtable_hyp_unmap(&pkvm_pgtable, addr, size); + + return (ret != size) ? -EFAULT : 0; +} + static int check_share(struct pkvm_mem_share *share) { const struct pkvm_mem_transition *tx = &share->tx; @@ -610,6 +649,82 @@ static int do_share(struct pkvm_mem_share *share) return WARN_ON(__do_share(share)); } +static int check_unshare(struct pkvm_mem_share *share) +{ + const struct pkvm_mem_transition *tx = &share->tx; + u64 completer_addr; + int ret; + + switch (tx->initiator.id) { + case PKVM_ID_HOST: + ret = host_request_unshare(&completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + if (ret) + return ret; + + switch (tx->completer.id) { + case PKVM_ID_HYP: + ret = hyp_ack_unshare(completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + return ret; +} + +static int __do_unshare(struct pkvm_mem_share *share) +{ + const struct pkvm_mem_transition *tx = &share->tx; + u64 completer_addr; + int ret; + + switch (tx->initiator.id) { + case PKVM_ID_HOST: + ret = host_initiate_unshare(&completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + if (ret) + return ret; + + switch (tx->completer.id) { + case PKVM_ID_HYP: + ret = hyp_complete_unshare(completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + return ret; +} + +/* + * do_unshare(): + * + * The page owner revokes access from another component for a range of + * pages which were previously shared using do_share(). + * + * Initiator: SHARED_OWNED => OWNED + * Completer: SHARED_BORROWED => NOPAGE + */ +static int do_unshare(struct pkvm_mem_share *share) +{ + int ret; + + ret = check_unshare(share); + if (ret) + return ret; + + return WARN_ON(__do_unshare(share)); +} + int __pkvm_host_share_hyp(u64 pfn) { int ret; -- 2.33.0.1079.g6e70778dc9-goog _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm