From patchwork Wed Dec 1 17:04:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Perret X-Patchwork-Id: 12694359 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3E0CEC433EF for ; Wed, 1 Dec 2021 17:11:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:References: Mime-Version:Message-Id:In-Reply-To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=qFyanYuuAFcAd/9K5QxnCl2MN1b9drC2xtT32vlkZ+s=; b=VTgwNh7Z/2juLuFeHrmTchasMI /aJlS3ASNpd5RbARqilIPEz4vMrayZbYOSw2y9fSaNP13N8/9iyHNt5JY79Kd1OLFXHEA8RWKJfhB HjSfGHpyyQvZc8UhC+aqDFb+fQWygRlA0fJ0+MHODMRuzqRheKArRYl/zJh8DPw4LusR3rmqzQLmJ Gw0PIrBvGadHR+b+8QCVjHq4GTiZlDtlNz/iU/dO7W1Il161l8YRgl42HmpM+6BwOx0SijQDDD/xj 0xzwZyyAZQzka9g1oic6Tb53TgEZnPum/walIeMOesz6eMwGVUTRakwiNOLa1KNJO2sL2Ao8B3m8w Ib0xC7pQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1msT6n-009UGq-Ka; Wed, 01 Dec 2021 17:09:30 +0000 Received: from mail-wr1-x44a.google.com ([2a00:1450:4864:20::44a]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1msT2V-009S4W-D9 for linux-arm-kernel@lists.infradead.org; Wed, 01 Dec 2021 17:05:04 +0000 Received: by mail-wr1-x44a.google.com with SMTP id p3-20020a056000018300b00186b195d4ddso4461493wrx.15 for ; Wed, 01 Dec 2021 09:05:02 -0800 (PST) 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=5wiVz7SPfRWryEm8NS78CviZAnf1vSptd9MDigwGN/4=; b=dCzRG28Wf9Hc1Tp8I8w9ve3Vw14cFJY4sy6ylndkDIvYcMBINBhYfEJQuT0z5jDNv1 tGtQIA4ScW62n9Y8NpIUEIAJPgcSiROzIIIoCmndHzXPxCyEyLTWbrESkPqQWrUF0K3p 9QOXgt39AuSkMUAbxmR0DvTI8l7eczc4wPKt+PgNh5XCms6IJXMamETMAzof/W4pXV0T wnKviJ2j0cYtPfs9cxEqyXVW4TErhwlx3FItlrJ0wzbTGP5qUqcJTqBUJ9hz1JfBV9P4 ym+hRGvYhdZTese4GXjjv7hVrbAqdUmjbu/PvO4zHWFnvI9MLZYIxoYlqL/MNIHhDMLB fBTQ== 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=5wiVz7SPfRWryEm8NS78CviZAnf1vSptd9MDigwGN/4=; b=bbmRhaBdoGoELQg4Id4zIHTe9wZk0DegtSsoXn4zGrP9TbLcfpbsC1eHAX9iF8ura5 lYwOK2ITQv20RoNDZ2OzwFj2P2scsoY+CDvi3gHUFxpi/hIvklkeq4AwbZKcducvaZQF CweI83hXPDUr8KoNH+Yk+Tl5x15c7gS/6dJE6toVyM0Urf/RiNxorf05Qc76cMYtfq9H MpJ1T6idlen1TbKRDZSy8hVTN55uy2m4NMMLF6sdXpAjUSw/A//zRZkvdnzNFadk1Sh5 MpPE3oWDq2o1eEXG3GKIwgDQliU1r91CZubP/PhotcIQht7Fv+d5JCa0f7Qs2hKx00uT A0JQ== X-Gm-Message-State: AOAM530tzU2W2tJoLbHlp1PwN5NhXF3HHs4Fka5hefeJ/yPzOtDv/i8X FMOJbJ4pUctyt4kubT8cgd2aKAnd91dp X-Google-Smtp-Source: ABdhPJwwAeEl/fBZkORhX4MxHC0CwsUHrjrNI+Tq88kiP5Hx0+90GQIUxvIJUedAX1Syxs87ImOEfCacsfMj X-Received: from luke.lon.corp.google.com ([2a00:79e0:d:210:1cab:1a20:2ef1:ddde]) (user=qperret job=sendgmr) by 2002:adf:ee04:: with SMTP id y4mr8657629wrn.0.1638378301567; Wed, 01 Dec 2021 09:05:01 -0800 (PST) Date: Wed, 1 Dec 2021 17:04:06 +0000 In-Reply-To: <20211201170411.1561936-1-qperret@google.com> Message-Id: <20211201170411.1561936-13-qperret@google.com> Mime-Version: 1.0 References: <20211201170411.1561936-1-qperret@google.com> X-Mailer: git-send-email 2.34.0.rc2.393.gf8c9666880-goog Subject: [PATCH v3 12/15] KVM: arm64: Implement __pkvm_host_share_hyp() using do_share() From: Quentin Perret To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kernel-team@android.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211201_090503_514849_EA6B745C X-CRM114-Status: GOOD ( 16.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Will Deacon __pkvm_host_share_hyp() shares memory between the host and the hypervisor so implement it as an invocation of the new do_share() mechanism. Note that double-sharing is no longer permitted (as this allows us to reduce the number of page-table walks significantly), but is thankfully no longer relied upon by the host. Signed-off-by: Will Deacon Signed-off-by: Quentin Perret --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 121 +++++++------------------- 1 file changed, 33 insertions(+), 88 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 74ca4043b08a..1282cbd6b9b3 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -370,94 +370,6 @@ static int host_stage2_idmap(u64 addr) return ret; } -static inline bool check_prot(enum kvm_pgtable_prot prot, - enum kvm_pgtable_prot required, - enum kvm_pgtable_prot denied) -{ - return (prot & (required | denied)) == required; -} - -int __pkvm_host_share_hyp(u64 pfn) -{ - phys_addr_t addr = hyp_pfn_to_phys(pfn); - enum kvm_pgtable_prot prot, cur; - void *virt = __hyp_va(addr); - enum pkvm_page_state state; - kvm_pte_t pte; - int ret; - - if (!addr_is_memory(addr)) - return -EINVAL; - - host_lock_component(); - hyp_lock_component(); - - ret = kvm_pgtable_get_leaf(&host_kvm.pgt, addr, &pte, NULL); - if (ret) - goto unlock; - if (!pte) - goto map_shared; - - /* - * Check attributes in the host stage-2 PTE. We need the page to be: - * - mapped RWX as we're sharing memory; - * - not borrowed, as that implies absence of ownership. - * Otherwise, we can't let it got through - */ - cur = kvm_pgtable_stage2_pte_prot(pte); - prot = pkvm_mkstate(0, PKVM_PAGE_SHARED_BORROWED); - if (!check_prot(cur, PKVM_HOST_MEM_PROT, prot)) { - ret = -EPERM; - goto unlock; - } - - state = pkvm_getstate(cur); - if (state == PKVM_PAGE_OWNED) - goto map_shared; - - /* - * Tolerate double-sharing the same page, but this requires - * cross-checking the hypervisor stage-1. - */ - if (state != PKVM_PAGE_SHARED_OWNED) { - ret = -EPERM; - goto unlock; - } - - ret = kvm_pgtable_get_leaf(&pkvm_pgtable, (u64)virt, &pte, NULL); - if (ret) - goto unlock; - - /* - * If the page has been shared with the hypervisor, it must be - * already mapped as SHARED_BORROWED in its stage-1. - */ - cur = kvm_pgtable_hyp_pte_prot(pte); - prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_SHARED_BORROWED); - if (!check_prot(cur, prot, ~prot)) - ret = -EPERM; - goto unlock; - -map_shared: - /* - * If the page is not yet shared, adjust mappings in both page-tables - * while both locks are held. - */ - prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_SHARED_BORROWED); - ret = pkvm_create_mappings_locked(virt, virt + PAGE_SIZE, prot); - BUG_ON(ret); - - prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED); - ret = host_stage2_idmap_locked(addr, PAGE_SIZE, prot); - BUG_ON(ret); - -unlock: - hyp_unlock_component(); - host_unlock_component(); - - return ret; -} - void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt) { struct kvm_vcpu_fault_info fault; @@ -708,3 +620,36 @@ static int do_share(struct pkvm_mem_share *share) return WARN_ON(__do_share(share)); } + +int __pkvm_host_share_hyp(u64 pfn) +{ + int ret; + u64 host_addr = hyp_pfn_to_phys(pfn); + u64 hyp_addr = (u64)__hyp_va(host_addr); + struct pkvm_mem_share share = { + .tx = { + .nr_pages = 1, + .initiator = { + .id = PKVM_ID_HOST, + .addr = host_addr, + .host = { + .completer_addr = hyp_addr, + }, + }, + .completer = { + .id = PKVM_ID_HYP, + }, + }, + .prot = PAGE_HYP, + }; + + host_lock_component(); + hyp_lock_component(); + + ret = do_share(&share); + + hyp_unlock_component(); + host_unlock_component(); + + return ret; +}