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 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 DD5F7D2FEE3 for ; Tue, 27 Jan 2026 19:36:06 +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:MIME-Version:In-Reply-To:References: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=TSjXDXrH9QPJGZb1G3VVT+tcBIvybdQk8SWTrjMdvFE=; b=lvHHtxNdyYHMTe X6Kif0+zdUaUshmeOc19DNiCPl74DOJS3pigjPwzAtkemOA4lcd+jSQn0LL7WmFuxFmOBd/BE7S2K 3X5hF8LxkVDdn1HexD97htL79wtk9PEmgOoM5BqFIGyrXkFCkJcWKHPpEdfbm/+hV7bonKRYWJf2M hzOAB92U4L3p5jSRRUnyGGy/+m3Bgnf86vErqJ6QygqrbwqTJ9OXqgPjXIeEtbgY9FKGURZUlBWG7 NRbELh2nwn5ogKxIPERNGbPpx+0grC06NnptDdHjUmQW0R46dXmvCoXp7DRLkk3otjDtleHhHuj5z NAM3bd4FSYxLlYnOX3YA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkoqp-0000000EvtV-1AbC; Tue, 27 Jan 2026 19:35:47 +0000 Received: from fra-out-005.esa.eu-central-1.outbound.mail-perimeter.amazon.com ([63.176.194.123]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkPnJ-0000000CtkL-0XKk; Mon, 26 Jan 2026 16:50:31 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.co.uk; i=@amazon.co.uk; q=dns/txt; s=amazoncorp2; t=1769446229; x=1800982229; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=Z+0YCRdTDnWSs97jpjMZOSlIedfR2zbQnGU/yn7jp+s=; b=q4bxCu7DP3JP5Y3NSevEICx/SHASuQR1MHaRlH8iuwxlD6s9k5RkGKmP qzSqUKLKXoLwJH/wuLeL2qynX5Qfaqo/gFZ+1TsxZAK3RcXysdwyU9Y+q zgJ3Tq64YPZ0mLsI0dlQAwj0r5obclIEmcXHOSgJwCcD+86lws03V4IpH SAmBecb5pSMSTng97iEvPJD3IgdpSAFxTTszU17oiRWTu7hvCkf8XOhJs iY3f5lUIdmfWGWfkZE5BOA0cyCB8xqwsVkjQP63Bi1JR20PygUjs2ZS2h +ZHy5H0anSJYUTMWG4bhLMR76EE2t0b5TccoiMGOaYZs1gDw7msq/eokE g==; X-CSE-ConnectionGUID: u2oaZC4NS1OsnhY1SRBC7A== X-CSE-MsgGUID: Pxs/ngYXSYK56Rj63xFgrw== X-IronPort-AV: E=Sophos;i="6.21,255,1763424000"; d="scan'208";a="8462653" Received: from ip-10-6-11-83.eu-central-1.compute.internal (HELO smtpout.naws.eu-central-1.prod.farcaster.email.amazon.dev) ([10.6.11.83]) by internal-fra-out-005.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2026 16:50:21 +0000 Received: from EX19MTAEUB002.ant.amazon.com [54.240.197.224:11258] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.13.191:2525] with esmtp (Farcaster) id 0c98ffad-9331-4293-9e93-229526262b2a; Mon, 26 Jan 2026 16:50:21 +0000 (UTC) X-Farcaster-Flow-ID: 0c98ffad-9331-4293-9e93-229526262b2a Received: from EX19D005EUB002.ant.amazon.com (10.252.51.103) by EX19MTAEUB002.ant.amazon.com (10.252.51.79) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.35; Mon, 26 Jan 2026 16:50:21 +0000 Received: from EX19D005EUB003.ant.amazon.com (10.252.51.31) by EX19D005EUB002.ant.amazon.com (10.252.51.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.35; Mon, 26 Jan 2026 16:50:20 +0000 Received: from EX19D005EUB003.ant.amazon.com ([fe80::b825:becb:4b38:da0c]) by EX19D005EUB003.ant.amazon.com ([fe80::b825:becb:4b38:da0c%3]) with mapi id 15.02.2562.035; Mon, 26 Jan 2026 16:50:20 +0000 From: "Kalyazin, Nikita" To: "kvm@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "bpf@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "kernel@xen0n.name" , "linux-riscv@lists.infradead.org" , "linux-s390@vger.kernel.org" , "loongarch@lists.linux.dev" CC: "pbonzini@redhat.com" , "corbet@lwn.net" , "maz@kernel.org" , "oupton@kernel.org" , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "yuzenghui@huawei.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "seanjc@google.com" , "tglx@kernel.org" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "luto@kernel.org" , "peterz@infradead.org" , "willy@infradead.org" , "akpm@linux-foundation.org" , "david@kernel.org" , "lorenzo.stoakes@oracle.com" , "vbabka@suse.cz" , "rppt@kernel.org" , "surenb@google.com" , "mhocko@suse.com" , "ast@kernel.org" , "daniel@iogearbox.net" , "andrii@kernel.org" , "martin.lau@linux.dev" , "eddyz87@gmail.com" , "song@kernel.org" , "yonghong.song@linux.dev" , "john.fastabend@gmail.com" , "kpsingh@kernel.org" , "sdf@fomichev.me" , "haoluo@google.com" , "jolsa@kernel.org" , "jgg@ziepe.ca" , "jhubbard@nvidia.com" , "peterx@redhat.com" , "jannh@google.com" , "pfalcato@suse.de" , "shuah@kernel.org" , "riel@surriel.com" , "ryan.roberts@arm.com" , "jgross@suse.com" , "yu-cheng.yu@intel.com" , "kas@kernel.org" , "coxu@redhat.com" , "kevin.brodsky@arm.com" , "ackerleytng@google.com" , "maobibo@loongson.cn" , "prsampat@amd.com" , "mlevitsk@redhat.com" , "jmattson@google.com" , "jthoughton@google.com" , "agordeev@linux.ibm.com" , "alex@ghiti.fr" , "aou@eecs.berkeley.edu" , "borntraeger@linux.ibm.com" , "chenhuacai@kernel.org" , "dev.jain@arm.com" , "gor@linux.ibm.com" , "hca@linux.ibm.com" , "palmer@dabbelt.com" , "pjw@kernel.org" , "shijie@os.amperecomputing.com" , "svens@linux.ibm.com" , "thuth@redhat.com" , "wyihan@google.com" , "yang@os.amperecomputing.com" , "Jonathan.Cameron@huawei.com" , "Liam.Howlett@oracle.com" , "urezki@gmail.com" , "zhengqi.arch@bytedance.com" , "gerald.schaefer@linux.ibm.com" , "jiayuan.chen@shopee.com" , "lenb@kernel.org" , "osalvador@suse.de" , "pavel@kernel.org" , "rafael@kernel.org" , "vannapurve@google.com" , "jackmanb@google.com" , "aneesh.kumar@kernel.org" , "patrick.roy@linux.dev" , "Thomson, Jack" , "Itazuri, Takahiro" , "Manwaring, Derek" , "Cali, Marco" , "Kalyazin, Nikita" Subject: [PATCH v10 08/15] KVM: arm64: define kvm_arch_gmem_supports_no_direct_map() Thread-Topic: [PATCH v10 08/15] KVM: arm64: define kvm_arch_gmem_supports_no_direct_map() Thread-Index: AQHcjuPbS80kQwcCmUC50XT6X/2MWg== Date: Mon, 26 Jan 2026 16:50:20 +0000 Message-ID: <20260126164445.11867-9-kalyazin@amazon.com> References: <20260126164445.11867-1-kalyazin@amazon.com> In-Reply-To: <20260126164445.11867-1-kalyazin@amazon.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.19.103.116] MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260126_085029_447455_DFB22567 X-CRM114-Status: UNSURE ( 9.97 ) X-CRM114-Notice: Please train this message. X-Mailman-Approved-At: Tue, 27 Jan 2026 11:35:38 -0800 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Patrick Roy Support for GUEST_MEMFD_FLAG_NO_DIRECT_MAP on arm64 depends on 1) direct map manipulations at 4k granularity being possible, and 2) FEAT_S2FWB. 1) is met whenever the direct map is set up at 4k granularity (e.g. not with huge/gigantic pages) at boottime, as due to ARM's break-before-make semantics, breaking huge mappings into 4k mappings in the direct map is not possible (BBM would require temporary invalidation of the entire huge mapping, even if only a 4k subrange should be zapped, which will probably crash the kernel). However, the current default for rodata_full is true, which forces a 4k direct map. 2) is required to allow KVM to elide cache coherency operations when installing stage 2 page tables, which require the direct map to be entry for the newly mapped memory to be present (which it will not be, as guest_memfd would have removed direct map entries in kvm_gmem_get_pfn()). Cc: Will Deacon Signed-off-by: Patrick Roy Signed-off-by: Nikita Kalyazin --- arch/arm64/include/asm/kvm_host.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index ac7f970c7883..d431ca7d4fc9 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -1654,5 +1655,17 @@ static __always_inline enum fgt_group_id __fgt_reg_to_group_id(enum vcpu_sysreg \ p; \ }) +#ifdef CONFIG_KVM_GUEST_MEMFD +static inline bool kvm_arch_gmem_supports_no_direct_map(void) +{ + /* + * Without FWB, direct map access is needed in kvm_pgtable_stage2_map(), + * as it calls dcache_clean_inval_poc(). + */ + return can_set_direct_map() && cpus_have_final_cap(ARM64_HAS_STAGE2_FWB); +} +#define kvm_arch_gmem_supports_no_direct_map kvm_arch_gmem_supports_no_direct_map +#endif /* CONFIG_KVM_GUEST_MEMFD */ + #endif /* __ARM64_KVM_HOST_H__ */ -- 2.50.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv