From patchwork Mon Mar 3 13:08:36 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikita Kalyazin X-Patchwork-Id: 13998807 Received: from smtp-fw-80007.amazon.com (smtp-fw-80007.amazon.com [99.78.197.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C3D41210F59; Mon, 3 Mar 2025 13:08:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.218 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741007329; cv=none; b=tcCFC1K7KPOPGFLXDwrsxjSxn2PyO+l/floC12kmwGjn4ncLmDuBY+O7K/3KfbmAxEyYPfQHghc1+3S0/kmxAJKCyVitp+6zi5lnPgwR3dsyOdw+5X1jqrApiJgSRUEcVxU6+eiS8TH8bxg4CZ2L45XNXnENPgd5hZdgRoAN7PI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741007329; c=relaxed/simple; bh=uylAwl9z4lLSLbtftXMVsVSfo+l6pIl66/zaUNQcLB0=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=skrXokXU853by9KIxiQ1XE+7kJzWJPULPDhjtrS85esV5tjD07Ns4Vl6P8WVskMsDN5l4gTm2nFidAPHqdBPkXN6kNIRmQfBED6v+W0roNcO+q6GsjzNHCrfix0GAPBawgdZvEgLENdmcWJoF4W7F5qPp9I1aQ98xd1gGxzVHJo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.uk; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=VDXy9l2Z; arc=none smtp.client-ip=99.78.197.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="VDXy9l2Z" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1741007328; x=1772543328; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=ijLS6/7VoNS5QgB9vq9v8BcogTKboYMwaB+vjiqquWQ=; b=VDXy9l2Zu9p7ohCfcZOJ9vRCae8CYq5vvLUv2tRSBLYo/HiW4psz9Qkt Mj4PXQyj+5BMd4fycVb6Sh9agQrNpbk+ny4LNPm3Jppv5/7jNmT0X9ij9 weYDqRtNq3BFdhg+qqx02E5nEY2tKj1uBRet1M/l5/HYx06yPQXyUyluO g=; X-IronPort-AV: E=Sophos;i="6.13,329,1732579200"; d="scan'208";a="382575094" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.25.36.210]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2025 13:08:46 +0000 Received: from EX19MTAEUB002.ant.amazon.com [10.0.43.254:35314] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.24.106:2525] with esmtp (Farcaster) id c10353bf-5d23-44b0-9a7e-a591baedecbb; Mon, 3 Mar 2025 13:08:44 +0000 (UTC) X-Farcaster-Flow-ID: c10353bf-5d23-44b0-9a7e-a591baedecbb Received: from EX19D015EUB003.ant.amazon.com (10.252.51.113) by EX19MTAEUB002.ant.amazon.com (10.252.51.59) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 3 Mar 2025 13:08:40 +0000 Received: from EX19MTAUEA002.ant.amazon.com (10.252.134.9) by EX19D015EUB003.ant.amazon.com (10.252.51.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 3 Mar 2025 13:08:40 +0000 Received: from email-imr-corp-prod-iad-all-1b-3ae3de11.us-east-1.amazon.com (10.43.8.2) by mail-relay.amazon.com (10.252.134.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14 via Frontend Transport; Mon, 3 Mar 2025 13:08:40 +0000 Received: from dev-dsk-kalyazin-1a-a12e27e2.eu-west-1.amazon.com (dev-dsk-kalyazin-1a-a12e27e2.eu-west-1.amazon.com [172.19.103.116]) by email-imr-corp-prod-iad-all-1b-3ae3de11.us-east-1.amazon.com (Postfix) with ESMTPS id E2BB7A065C; Mon, 3 Mar 2025 13:08:38 +0000 (UTC) From: Nikita Kalyazin To: , CC: , , , , , , , , , , , , , , , Subject: [v3 PATCH 0/2] KVM: guest_memfd: use write for population Date: Mon, 3 Mar 2025 13:08:36 +0000 Message-ID: <20250303130838.28812-1-kalyazin@amazon.com> X-Mailer: git-send-email 2.47.1 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This series is rebased on top of Fuad's v4 for shared mapping of guest_memfd [1]. Change since v2 [2]: - David/Mike D: Only compile support for the write syscall if CONFIG_KVM_GMEM_SHARED_MEM introduced in [1] is enabled. In non-CoCo use cases where the host can access guest memory, guest_memfd can be allocated and populated via the write syscall. Even though the same can also be achieved via userspace mapping and memcpy from userspace, write provides a more performant option because it 1) avoids double initialisation as the kernel does not need to zero pages and 2) does not require setting up page tables. Nikita [1] https://lore.kernel.org/kvm/20250218172500.807733-4-tabba@google.com/T/ [2] https://lore.kernel.org/kvm/20241129123929.64790-1-kalyazin@amazon.com/T/ Nikita Kalyazin (2): KVM: guest_memfd: add generic population via write KVM: selftests: update guest_memfd write tests .../testing/selftests/kvm/guest_memfd_test.c | 85 +++++++++++++++-- virt/kvm/guest_memfd.c | 94 ++++++++++++++++++- 2 files changed, 170 insertions(+), 9 deletions(-) base-commit: 005f6404708d430abab7fab9b422d0daf6e0c2fe