From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6022A3E51F1 for ; Mon, 23 Mar 2026 23:59:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774310362; cv=none; b=IWuCjXI6hXCBHlcG76tuiTVNcBbRGEDOA6x0MwX7JkDzhz0kfCTzIxc8k7hPObRs/jq5fWX0k6NctEaUvWv0PB9SkrHzxJV2c349vDXOBqETi2+vqwNR+FmKt07c9RL29TqUURDg0eiwGqAMx1z0XZmpEb3n0XOWlKpXaA4hRQ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774310362; c=relaxed/simple; bh=vpHjJ0pn077dUCj9wV/y1NEgQP72set6GB5RHBGwAdM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=QCg1V15cZD8f9oKlUD8ulmAKlto5L4NL9bWyuQVfDE1r6XwWiisT90cZDmu0C9zBsM+BZvaqQ0b0ECYSoipRBt973k2sMN97SCE77dR4c6WCcWbL5wfPUON98rqRlWjd0TEjvxBsdZXaY34GNGzS1MZ7Gge9OKhQWrars/ItEHs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--dmatlack.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=iHCuUcD1; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--dmatlack.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iHCuUcD1" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2b05a3c2421so8473075ad.1 for ; Mon, 23 Mar 2026 16:59:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1774310360; x=1774915160; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=emXTkfduCARpReH/0NkUqCqksAosTTU4j/dciIvOyCs=; b=iHCuUcD1MXluPlFGR9QaLpMovlhc43mYSiP5FnvngghaPKZCwxqWpBQ3l97AKVY4mm C+lIG/50aD4f5beKECih57U0jbIXYtpKSbNL3+jm78RPQgp4ZD1sCB3QcSUASbBfyFrU pefSw9WULtAHhzcEbXM26XiSMtvMc7jp3fVTiHPrBRyNigX5umOTiJeC8VHI5uUhK3FL tCXfDiVgjAzi7ThSb1TK6HACV9WyNK77Cv7Rg9BC5NOg9mquA+OSggYPcB8nrBshn3bU +ZFoZMPQxqpzmYW7U6y/rvzPLcolxmBFzUOpHiEDHe+/JH+7qv7Xv0tePHYuTu5JYwiF UM0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774310360; x=1774915160; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=emXTkfduCARpReH/0NkUqCqksAosTTU4j/dciIvOyCs=; b=qcUxKm+Ix6CxBo4megyqXu7gNevEx4CPdci+JDAo9YpAhRlecbr2MZOf2ctIA0dk1s pcMJGf3h8YRJ0j+gTUqeBx1o+2zF5Ydf1aZWMs5axZLOSxSyUVY7EkxqPXqtMVx+V+Uq 99W9Hv66iHU8jnpBEvlTtteMHYIY9fMpNAlYCC80rTGXG0vz6ulK3c6MJk7VaUn4Vy2I ykZRMkOrDUoxe5B8coJaeU4xsuQOIjgGEPm9Hw3//w9oVKHQIq0OgYUfV4SMweVATI3h V13g25VE7CND3S1NvwQzrPzubuoRfAL1EY+uYVdS5ywm+FpAHpuSuPwWRd9dp3Q2tI/a Cp7g== X-Forwarded-Encrypted: i=1; AJvYcCX29In+sT2ciQlDFvKMUQ6eZOV3y5y50qEyToYvWhMFFmcsTBxigAwvNru9P9bYb+S79/oHXzre9Xs=@vger.kernel.org X-Gm-Message-State: AOJu0Yw3RvE2qTflA7URT0Rt6QE0+YYcdlvI/6DcO+KlIwlqVlkaHTcN 3SkBvyDXV1ouxcdMFAvlIeJyKh0tKToO1F96KB2HAArbXcNaW+H2DHybNhuOGXJanTs1cFBgGI1 7P8jOrcyfxlhx4g== X-Received: from plcp2.prod.google.com ([2002:a17:902:e342:b0:2b0:6c44:fc55]) (user=dmatlack job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:d54a:b0:2ae:c9be:5f2c with SMTP id d9443c01a7336-2b08271d042mr130329495ad.21.1774310359658; Mon, 23 Mar 2026 16:59:19 -0700 (PDT) Date: Mon, 23 Mar 2026 23:58:16 +0000 In-Reply-To: <20260323235817.1960573-1-dmatlack@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260323235817.1960573-1-dmatlack@google.com> X-Mailer: git-send-email 2.53.0.983.g0bb29b3bc5-goog Message-ID: <20260323235817.1960573-25-dmatlack@google.com> Subject: [PATCH v3 24/24] vfio: selftests: Add continuous DMA to vfio_pci_liveupdate_kexec_test From: David Matlack To: Alex Williamson , Bjorn Helgaas Cc: Adithya Jayachandran , Alexander Graf , Alex Mastro , Andrew Morton , Ankit Agrawal , Arnd Bergmann , Askar Safin , "Borislav Petkov (AMD)" , Chris Li , Dapeng Mi , David Matlack , David Rientjes , Feng Tang , Jacob Pan , Jason Gunthorpe , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Kees Cook , Kevin Tian , kexec@lists.infradead.org, kvm@vger.kernel.org, Leon Romanovsky , Leon Romanovsky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Li RongQing , Lukas Wunner , Marco Elver , "=?UTF-8?q?Micha=C5=82=20Winiarski?=" , Mike Rapoport , Parav Pandit , Pasha Tatashin , "Paul E. McKenney" , Pawan Gupta , "Peter Zijlstra (Intel)" , Pranjal Shrivastava , Pratyush Yadav , Raghavendra Rao Ananta , Randy Dunlap , Rodrigo Vivi , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Vipin Sharma , Vivek Kasireddy , William Tu , Yi Liu , Zhu Yanjun Content-Type: text/plain; charset="UTF-8" Add a long-running DMA memcpy operation to vfio_pci_liveupdate_kexec_test so that the device attempts to perform DMAs continuously during the Live Update. At this point iommufd preservation is not supported and bus mastering is not kept enabled on the device during across the kexec, so most of these DMAs will be dropped. However this test ensures that the current device preservation support does not lead to system instability or crashes if the device is active. And once iommufd and bus mastering are preserved, this test can be relaxed to check that the DMA operations completed successfully. Signed-off-by: David Matlack --- .../vfio/vfio_pci_liveupdate_kexec_test.c | 129 ++++++++++++++++++ 1 file changed, 129 insertions(+) diff --git a/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c b/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c index 65c48196e44e..36bddfbb88ed 100644 --- a/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c +++ b/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c @@ -1,8 +1,16 @@ // SPDX-License-Identifier: GPL-2.0-only +#include +#include + #include #include +#define MEMCPY_SIZE SZ_1G +#define DRIVER_SIZE SZ_1M +#define MEMFD_SIZE (MEMCPY_SIZE + DRIVER_SIZE) + +static struct dma_region memcpy_region; static const char *device_bdf; static char state_session[LIVEUPDATE_SESSION_NAME_LENGTH]; @@ -11,8 +19,89 @@ static char device_session[LIVEUPDATE_SESSION_NAME_LENGTH]; enum { STATE_TOKEN, DEVICE_TOKEN, + MEMFD_TOKEN, }; +static void dma_memcpy_one(struct vfio_pci_device *device) +{ + void *src = memcpy_region.vaddr, *dst; + u64 size; + + size = min_t(u64, memcpy_region.size / 2, device->driver.max_memcpy_size); + dst = src + size; + + memset(src, 1, size); + memset(dst, 0, size); + + printf("Kicking off 1 DMA memcpy operations of size 0x%lx...\n", size); + vfio_pci_driver_memcpy(device, + to_iova(device, src), + to_iova(device, dst), + size); + + VFIO_ASSERT_EQ(memcmp(src, dst, size), 0); +} + +static void dma_memcpy_start(struct vfio_pci_device *device) +{ + void *src = memcpy_region.vaddr, *dst; + u64 count, size; + + size = min_t(u64, memcpy_region.size / 2, device->driver.max_memcpy_size); + dst = src + size; + + /* + * Rough Math: If we assume the device will perform memcpy at a rate of + * 30GB/s then 7200GB of transfers will run for about 4 minutes. + */ + count = (u64)7200 * SZ_1G / size; + count = min_t(u64, count, device->driver.max_memcpy_count); + + memset(src, 1, size / 2); + memset(dst, 0, size / 2); + + printf("Kicking off %lu DMA memcpy operations of size 0x%lx...\n", count, size); + vfio_pci_driver_memcpy_start(device, + to_iova(device, src), + to_iova(device, dst), + size, count); +} + +static void dma_memfd_map(struct vfio_pci_device *device, int fd) +{ + void *vaddr; + + vaddr = mmap(NULL, MEMFD_SIZE, PROT_WRITE, MAP_SHARED, fd, 0); + VFIO_ASSERT_NE(vaddr, MAP_FAILED); + + memcpy_region.iova = SZ_4G; + memcpy_region.size = MEMCPY_SIZE; + memcpy_region.vaddr = vaddr; + iommu_map(device->iommu, &memcpy_region); + + device->driver.region.iova = memcpy_region.iova + memcpy_region.size; + device->driver.region.size = DRIVER_SIZE; + device->driver.region.vaddr = vaddr + memcpy_region.size; + iommu_map(device->iommu, &device->driver.region); +} + +static void dma_memfd_setup(struct vfio_pci_device *device, int session_fd) +{ + int fd, ret; + + fd = memfd_create("dma-buffer", 0); + VFIO_ASSERT_GE(fd, 0); + + ret = fallocate(fd, 0, 0, MEMFD_SIZE); + VFIO_ASSERT_EQ(ret, 0); + + printf("Preserving memfd of size 0x%x in session\n", MEMFD_SIZE); + ret = luo_session_preserve_fd(session_fd, fd, MEMFD_TOKEN); + VFIO_ASSERT_EQ(ret, 0); + + dma_memfd_map(device, fd); +} + static void before_kexec(int luo_fd) { struct vfio_pci_device *device; @@ -32,6 +121,27 @@ static void before_kexec(int luo_fd) ret = luo_session_preserve_fd(session_fd, device->fd, DEVICE_TOKEN); VFIO_ASSERT_EQ(ret, 0); + dma_memfd_setup(device, session_fd); + + /* + * If the device has a selftests driver, kick off a long-running DMA + * operation to exercise the device trying to DMA during a Live Update. + * Since iommufd preservation is not supported yet, these DMAs should be + * dropped. So this is just looking to verify that the system does not + * fall over and crash as a result of a busy device being preserved. + */ + if (device->driver.ops) { + vfio_pci_driver_init(device); + dma_memcpy_start(device); + + /* + * Disable interrupts on the device or freeze() will fail. + * Unfortunately there isn't a way to easily have a test for + * that here since the check happens during shutdown. + */ + vfio_pci_msix_disable(device); + } + close(luo_fd); daemonize_and_wait(); } @@ -78,6 +188,7 @@ static void after_kexec(int luo_fd, int state_session_fd) struct iommu *iommu; int session_fd; int device_fd; + int memfd; int stage; check_open_vfio_device_fails(); @@ -88,6 +199,10 @@ static void after_kexec(int luo_fd, int state_session_fd) session_fd = luo_retrieve_session(luo_fd, device_session); VFIO_ASSERT_GE(session_fd, 0); + printf("Retrieving memfd from LUO\n"); + memfd = luo_session_retrieve_fd(session_fd, MEMFD_TOKEN); + VFIO_ASSERT_GE(memfd, 0); + printf("Finishing the session before retrieving the device (should fail)\n"); VFIO_ASSERT_NE(luo_session_finish(session_fd), 0); @@ -109,9 +224,23 @@ static void after_kexec(int luo_fd, int state_session_fd) */ device = __vfio_pci_device_init(device_bdf, iommu, device_fd); + dma_memfd_map(device, memfd); + printf("Finishing the session\n"); VFIO_ASSERT_EQ(luo_session_finish(session_fd), 0); + /* + * Once iommufd preservation is supported and the device is kept fully + * running across the Live Update, this should wait for the long- + * running DMA memcpy operation kicked off in before_kexec() to + * complete. But for now we expect the device to be reset so just + * trigger a single memcpy to make sure it's still functional. + */ + if (device->driver.ops) { + vfio_pci_driver_init(device); + dma_memcpy_one(device); + } + vfio_pci_device_cleanup(device); iommu_cleanup(iommu); } -- 2.53.0.983.g0bb29b3bc5-goog