From patchwork Wed Aug 21 15:38:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 13771846 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 8A08AC52D7C for ; Wed, 21 Aug 2024 15:48:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=wViaZ7usSJnK+wMFBxorlZBu2BB5+TvbeIXfHxfZuiM=; b=4yOnWU2rl/48E0j/7F5T5qOXBH cDJpX4qWDWMf3eS8kyZR+naoZpO3EDgRxN1uyu8YCmGyfy7855NwwmbjCuPJfiFXqWoR8+GOTIYrL AKq/ZZiXnyZG8ODUYuwKTBat+thEH4WIhuLafQzWHSc0/EHZJbMg7M/+HBGk1gH49Kj4B/9xG2rY4 TgLMVQGZMuxh/3V/zFp+wns2eyGlqcuV7qjSGCIZa8Jaul5Atsy8SxkBu+fX5MFvcew4h5hAsNaD3 1733RUjyYnHY3POTBHBNcHWXaFDSLhxP7YKXETOtoRwa/gLs2oiizqkobGqPLFCWy7ooivHEikgGy qMg1RLdQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sgnZl-00000009aHB-2WXG; Wed, 21 Aug 2024 15:48:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sgnRA-00000009X89-2L0F for linux-arm-kernel@lists.infradead.org; Wed, 21 Aug 2024 15:39:54 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 261AFDA7; Wed, 21 Aug 2024 08:40:18 -0700 (PDT) Received: from e122027.cambridge.arm.com (e122027.cambridge.arm.com [10.1.37.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 68F2F3F73B; Wed, 21 Aug 2024 08:39:49 -0700 (PDT) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun Subject: [PATCH v4 12/43] arm64: RME: Keep a spare page delegated to the RMM Date: Wed, 21 Aug 2024 16:38:13 +0100 Message-Id: <20240821153844.60084-13-steven.price@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240821153844.60084-1-steven.price@arm.com> References: <20240821153844.60084-1-steven.price@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240821_083952_727267_A98C368F X-CRM114-Status: GOOD ( 15.85 ) 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 Pages can only be populated/destroyed on the RMM at the 4KB granule, this requires creating the full depth of RTTs. However if the pages are going to be combined into a 2MB huge page the last RTT is only temporarily needed. Similarly when freeing memory the huge page must be temporarily split requiring temporary usage of the full depth oF RTTs. To avoid needing to perform a temporary allocation and delegation of a page for this purpose we keep a spare delegated page around. In particular this avoids the need for memory allocation while destroying the realm guest. Reviewed-by: Suzuki K Poulose Signed-off-by: Steven Price --- arch/arm64/include/asm/kvm_rme.h | 5 +++++ arch/arm64/kvm/rme.c | 8 ++++++++ 2 files changed, 13 insertions(+) diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h index 209cd99f03dd..bd306bd7b64b 100644 --- a/arch/arm64/include/asm/kvm_rme.h +++ b/arch/arm64/include/asm/kvm_rme.h @@ -50,6 +50,9 @@ enum realm_state { * @state: The lifetime state machine for the realm * @rd: Kernel mapping of the Realm Descriptor (RD) * @params: Parameters for the RMI_REALM_CREATE command + * @spare_page: A physical page that has been delegated to the Realm world but + * is otherwise free. Used to avoid temporary allocation during + * RTT operations. * @num_aux: The number of auxiliary pages required by the RMM * @vmid: VMID to be used by the RMM for the realm * @ia_bits: Number of valid Input Address bits in the IPA @@ -60,6 +63,8 @@ struct realm { void *rd; struct realm_params *params; + phys_addr_t spare_page; + unsigned long num_aux; unsigned int vmid; unsigned int ia_bits; diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c index 4d21ec5f2910..f6430d460519 100644 --- a/arch/arm64/kvm/rme.c +++ b/arch/arm64/kvm/rme.c @@ -104,6 +104,7 @@ static int realm_create_rd(struct kvm *kvm) } realm->rd = rd; + realm->spare_page = PHYS_ADDR_MAX; if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) { WARN_ON(rmi_realm_destroy(rd_phys)); @@ -286,6 +287,13 @@ void kvm_destroy_realm(struct kvm *kvm) rme_vmid_release(realm->vmid); + if (realm->spare_page != PHYS_ADDR_MAX) { + /* Leak the page if the undelegate fails */ + if (!WARN_ON(rmi_granule_undelegate(realm->spare_page))) + free_page((unsigned long)phys_to_virt(realm->spare_page)); + realm->spare_page = PHYS_ADDR_MAX; + } + for (i = 0; i < pgt->pgd_pages; i++) { phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;