From patchwork Thu May 19 13:40:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12854997 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 73908C433EF for ; Thu, 19 May 2022 13:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231309AbiESNoz (ORCPT ); Thu, 19 May 2022 09:44:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238927AbiESNnH (ORCPT ); Thu, 19 May 2022 09:43:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC58B3ED25 for ; Thu, 19 May 2022 06:43:05 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5D2056179E for ; Thu, 19 May 2022 13:43:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D396C36AE5; Thu, 19 May 2022 13:43:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652967784; bh=pr8cqSQ8LvDyMaXSEUTsEP4ASMbp/gW/nK760YXNIiY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E1ymsAlqWNYi4MaLBoT7GrxsUccaUMDmwKl4xv0+QaTqkv6BNMmmhOEAuscujcOn2 BuAgQSkWx0WQQFf7HlU5mA+F/75KfDuiAjH2rhSG7kS6I9e1A6/Evdd4/a7b8zD8Ns FgopfyyoMPQdR689n/Gy99tgOEZUEyFro3NIe29XtHkS5DpNrVp2Dp/5DI1iF4jBnc HSJaJCrp9DRebNcGq+DDrv/BRbY3JEcIN0yDexAeptt9G6doRvfEkKwqv/bMthhEld IEQOUak1DFZW4Q7DoJCtTYBjVXSYqx0z0XU3m4GuyuDEWOdq1HPq01YzU6HWJ1u98K l7lcgt2aNgRhg== From: Will Deacon To: kvmarm@lists.cs.columbia.edu Cc: Will Deacon , Ard Biesheuvel , Sean Christopherson , Alexandru Elisei , Andy Lutomirski , Catalin Marinas , James Morse , Chao Peng , Quentin Perret , Suzuki K Poulose , Michael Roth , Mark Rutland , Fuad Tabba , Oliver Upton , Marc Zyngier , kernel-team@android.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 10/89] KVM: arm64: Implement do_donate() helper for donating memory Date: Thu, 19 May 2022 14:40:45 +0100 Message-Id: <20220519134204.5379-11-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220519134204.5379-1-will@kernel.org> References: <20220519134204.5379-1-will@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Quentin Perret Transferring ownership information of a memory region from one component to another can be achieved using a "donate" operation, which results in the previous owner losing access to the underlying pages entirely. Implement a do_donate() helper, along the same lines as do_{un,}share, and provide this functionality for the host-{to,from}-hyp cases as this will later be used to donate/reclaim memory pages to store VM metadata at EL2. Signed-off-by: Quentin Perret --- arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 2 + arch/arm64/kvm/hyp/nvhe/mem_protect.c | 239 ++++++++++++++++++ 2 files changed, 241 insertions(+) diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index f5705a1e972f..c87b19b2d468 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -60,6 +60,8 @@ enum pkvm_component_id { int __pkvm_prot_finalize(void); int __pkvm_host_share_hyp(u64 pfn); int __pkvm_host_unshare_hyp(u64 pfn); +int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages); +int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages); bool addr_is_memory(phys_addr_t phys); int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot); diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index ff86f5bd230f..c30402737548 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -391,6 +391,9 @@ struct pkvm_mem_transition { /* Address in the completer's address space */ u64 completer_addr; } host; + struct { + u64 completer_addr; + } hyp; }; } initiator; @@ -404,6 +407,10 @@ struct pkvm_mem_share { const enum kvm_pgtable_prot completer_prot; }; +struct pkvm_mem_donation { + const struct pkvm_mem_transition tx; +}; + struct check_walk_data { enum pkvm_page_state desired; enum pkvm_page_state (*get_page_state)(kvm_pte_t pte); @@ -503,6 +510,46 @@ static int host_initiate_unshare(u64 *completer_addr, return __host_set_page_state_range(addr, size, PKVM_PAGE_OWNED); } +static int host_initiate_donation(u64 *completer_addr, + const struct pkvm_mem_transition *tx) +{ + u8 owner_id = tx->completer.id; + u64 size = tx->nr_pages * PAGE_SIZE; + + *completer_addr = tx->initiator.host.completer_addr; + return host_stage2_set_owner_locked(tx->initiator.addr, size, owner_id); +} + +static bool __host_ack_skip_pgtable_check(const struct pkvm_mem_transition *tx) +{ + return !(IS_ENABLED(CONFIG_NVHE_EL2_DEBUG) || + tx->initiator.id != PKVM_ID_HYP); +} + +static int __host_ack_transition(u64 addr, const struct pkvm_mem_transition *tx, + enum pkvm_page_state state) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + + if (__host_ack_skip_pgtable_check(tx)) + return 0; + + return __host_check_page_state_range(addr, size, state); +} + +static int host_ack_donation(u64 addr, const struct pkvm_mem_transition *tx) +{ + return __host_ack_transition(addr, tx, PKVM_NOPAGE); +} + +static int host_complete_donation(u64 addr, const struct pkvm_mem_transition *tx) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + u8 host_id = tx->completer.id; + + return host_stage2_set_owner_locked(addr, size, host_id); +} + static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte) { if (!kvm_pte_valid(pte)) @@ -523,6 +570,27 @@ static int __hyp_check_page_state_range(u64 addr, u64 size, return check_page_state_range(&pkvm_pgtable, addr, size, &d); } +static int hyp_request_donation(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.hyp.completer_addr; + return __hyp_check_page_state_range(addr, size, PKVM_PAGE_OWNED); +} + +static int hyp_initiate_donation(u64 *completer_addr, + const struct pkvm_mem_transition *tx) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + int ret; + + *completer_addr = tx->initiator.hyp.completer_addr; + ret = kvm_pgtable_hyp_unmap(&pkvm_pgtable, tx->initiator.addr, size); + return (ret != size) ? -EFAULT : 0; +} + static bool __hyp_ack_skip_pgtable_check(const struct pkvm_mem_transition *tx) { return !(IS_ENABLED(CONFIG_NVHE_EL2_DEBUG) || @@ -554,6 +622,16 @@ static int hyp_ack_unshare(u64 addr, const struct pkvm_mem_transition *tx) PKVM_PAGE_SHARED_BORROWED); } +static int hyp_ack_donation(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_NOPAGE); +} + static int hyp_complete_share(u64 addr, const struct pkvm_mem_transition *tx, enum kvm_pgtable_prot perms) { @@ -572,6 +650,15 @@ static int hyp_complete_unshare(u64 addr, const struct pkvm_mem_transition *tx) return (ret != size) ? -EFAULT : 0; } +static int hyp_complete_donation(u64 addr, + const struct pkvm_mem_transition *tx) +{ + void *start = (void *)addr, *end = start + (tx->nr_pages * PAGE_SIZE); + enum kvm_pgtable_prot prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_OWNED); + + return pkvm_create_mappings_locked(start, end, prot); +} + static int check_share(struct pkvm_mem_share *share) { const struct pkvm_mem_transition *tx = &share->tx; @@ -724,6 +811,94 @@ static int do_unshare(struct pkvm_mem_share *share) return WARN_ON(__do_unshare(share)); } +static int check_donation(struct pkvm_mem_donation *donation) +{ + const struct pkvm_mem_transition *tx = &donation->tx; + u64 completer_addr; + int ret; + + switch (tx->initiator.id) { + case PKVM_ID_HOST: + ret = host_request_owned_transition(&completer_addr, tx); + break; + case PKVM_ID_HYP: + ret = hyp_request_donation(&completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + if (ret) + return ret; + + switch (tx->completer.id){ + case PKVM_ID_HOST: + ret = host_ack_donation(completer_addr, tx); + break; + case PKVM_ID_HYP: + ret = hyp_ack_donation(completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + return ret; +} + +static int __do_donate(struct pkvm_mem_donation *donation) +{ + const struct pkvm_mem_transition *tx = &donation->tx; + u64 completer_addr; + int ret; + + switch (tx->initiator.id) { + case PKVM_ID_HOST: + ret = host_initiate_donation(&completer_addr, tx); + break; + case PKVM_ID_HYP: + ret = hyp_initiate_donation(&completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + if (ret) + return ret; + + switch (tx->completer.id){ + case PKVM_ID_HOST: + ret = host_complete_donation(completer_addr, tx); + break; + case PKVM_ID_HYP: + ret = hyp_complete_donation(completer_addr, tx); + break; + default: + ret = -EINVAL; + } + + return ret; +} + +/* + * do_donate(): + * + * The page owner transfers ownership to another component, losing access + * as a consequence. + * + * Initiator: OWNED => NOPAGE + * Completer: NOPAGE => OWNED + */ +static int do_donate(struct pkvm_mem_donation *donation) +{ + int ret; + + ret = check_donation(donation); + if (ret) + return ret; + + return WARN_ON(__do_donate(donation)); +} + int __pkvm_host_share_hyp(u64 pfn) { int ret; @@ -789,3 +964,67 @@ int __pkvm_host_unshare_hyp(u64 pfn) return ret; } + +int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages) +{ + int ret; + u64 host_addr = hyp_pfn_to_phys(pfn); + u64 hyp_addr = (u64)__hyp_va(host_addr); + struct pkvm_mem_donation donation = { + .tx = { + .nr_pages = nr_pages, + .initiator = { + .id = PKVM_ID_HOST, + .addr = host_addr, + .host = { + .completer_addr = hyp_addr, + }, + }, + .completer = { + .id = PKVM_ID_HYP, + }, + }, + }; + + host_lock_component(); + hyp_lock_component(); + + ret = do_donate(&donation); + + hyp_unlock_component(); + host_unlock_component(); + + return ret; +} + +int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages) +{ + int ret; + u64 host_addr = hyp_pfn_to_phys(pfn); + u64 hyp_addr = (u64)__hyp_va(host_addr); + struct pkvm_mem_donation donation = { + .tx = { + .nr_pages = nr_pages, + .initiator = { + .id = PKVM_ID_HYP, + .addr = hyp_addr, + .hyp = { + .completer_addr = host_addr, + }, + }, + .completer = { + .id = PKVM_ID_HOST, + }, + }, + }; + + host_lock_component(); + hyp_lock_component(); + + ret = do_donate(&donation); + + hyp_unlock_component(); + host_unlock_component(); + + return ret; +}