From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1BFFF3D47D9; Tue, 28 Apr 2026 23:25:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777418721; cv=none; b=o2X4C+mjTMmpLFmXE9k7xKMCaLiNBFnVSRq9zWxtl0IVNEmILF+pnK5uAytAVmenL1XtskipGVEvBHvmHh7WJdAvbPDKDNBUQjaoN+8zBJHASeep6n/SCdriRoRYRHHy1pgU/7vw/ozkChqxypK3RVNqFz4CGWAiiWnzvkSgZRU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777418721; c=relaxed/simple; bh=QI0czbPihibpXCD2kQtktaad48rPB1vkWaJ1I6GpYvk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Df6D2h/C1w/6A3rNvnrXMVgGrEYp5Zyv0ZBqoPEvkxORJJ+lL71zliEuyWKKTLW3bxqcoTznO1a06f8wYIefxP1Osl5muCOGOvFyYKq1qAbJnbjoL6E1HnkgScF0EIKFfXJ/5VDRQeNf/LVf8XXgreQq248fpKzdKo6lMXR7ILY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=orkSpLeY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="orkSpLeY" Received: by smtp.kernel.org (Postfix) with ESMTPS id F1086C2BCC4; Tue, 28 Apr 2026 23:25:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777418721; bh=QI0czbPihibpXCD2kQtktaad48rPB1vkWaJ1I6GpYvk=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=orkSpLeYcwzAa7qy5LM48A13FLHgij2k51J6yMyjX1stw7i/KE5YLcpXL7eSvB4uf zZcdEDlTRbY/9aPbl4y3IMYf4OCAjGOhvboey3xBFzIiByYL9HaUV/oiYCT5/+xxBX i6JZPg73USXXRrfhUdYGQ0VbKQ+zR6Smr9Evmae8eQw7+1fYFokYwwhQqoNTHZBuZv Nn8YFETKZ4ncjN5HcgAuAgkUhg8gmEt48NRaQuFg4DL5+l2kyIZY6MFKdUcPQu0or1 xDdNwv6egPsHnqKRsTCmkoF7JV+TimZk5lw9gUXXn7OtQwJPv+tIq/bVg/bqih8iTR Kt+WH9S3KQgug== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7395CCF9E3; Tue, 28 Apr 2026 23:25:20 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Tue, 28 Apr 2026 16:25:40 -0700 Subject: [PATCH RFC v5 45/53] KVM: selftests: Reset shared memory after hole-punching Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260428-gmem-inplace-conversion-v5-45-d8608ccfca22@google.com> References: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com> In-Reply-To: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com> To: aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, ira.weiny@intel.com, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Jason Gunthorpe , Vlastimil Babka Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, Ackerley Tng X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1777418714; l=2491; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=WSIF8DMlvu4DIEQtmUrMjtQfocHXchi9Geu1zzxLD0I=; b=kuPxD2GFOGoFfxlviY04qf8Sq3zByZ44zvRNeBcRqsFNI56KizuLJBgckTtLQ4utLIPJ7dv8b EBG4IOrjJg1ApGbwerboMAotA0X/Wbh8yTgowQ9HiOfeFlD83CgcFa6 X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Endpoint-Received: by B4 Relay for ackerleytng@google.com/20260225 with auth_id=649 X-Original-From: Ackerley Tng Reply-To: ackerleytng@google.com From: Ackerley Tng private_mem_conversions_test used to reset the shared memory that was used for the test to an initial pattern at the end of each test iteration. Then, it would punch out the pages, which would zero memory. Without in-place conversion, the resetting would write shared memory, and hole-punching will zero private memory, hence resetting the test to the state at the beginning of the for loop. With in-place conversion, resetting writes memory as shared, and hole-punching zeroes the same physical memory, hence undoing the reset done before the hole punch. Move the resetting after the hole-punching, and reset the entire PER_CPU_DATA_SIZE instead of just the tested range. With in-place conversion, this zeroes and then resets the same physical memory. Without in-place conversion, the private memory is zeroed, and the shared memory is reset to init_p. This is sufficient since at each test stage, the memory is assumed to start as shared, and private memory is always assumed to start zeroed. Conversion zeroes memory, so the future test stages will work as expected. Fixes: 43f623f350ce1 ("KVM: selftests: Add x86-only selftest for private memory conversions") Signed-off-by: Ackerley Tng --- tools/testing/selftests/kvm/x86/private_mem_conversions_test.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c index 861baff201e78..289ad10063fca 100644 --- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c +++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c @@ -202,15 +202,18 @@ static void guest_test_explicit_conversion(u64 base_gpa, bool do_fallocate) guest_sync_shared(gpa, size, p3, p4); memcmp_g(gpa, p4, size); - /* Reset the shared memory back to the initial pattern. */ - memset((void *)gpa, init_p, size); - /* * Free (via PUNCH_HOLE) *all* private memory so that the next * iteration starts from a clean slate, e.g. with respect to * whether or not there are pages/folios in guest_mem. */ guest_map_shared(base_gpa, PER_CPU_DATA_SIZE, true); + + /* + * Hole-punching above zeroed private memory. Reset shared + * memory in preparation for the next GUEST_STAGE. + */ + memset((void *)base_gpa, init_p, PER_CPU_DATA_SIZE); } } -- 2.54.0.545.g6539524ca2-goog