From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f51.google.com (mail-qv1-f51.google.com [209.85.219.51]) (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 E72A81EB5E1 for ; Fri, 9 Jan 2026 00:54:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767920084; cv=none; b=Bn9r6RcB5mRbp+hvA0MsgHoimCj8HgBM5lxFIzQHwgPVDHGSZHcGOH3JiSQLg8QCdeBMcp+aYutwBJwZ2iACASap+BG/IHtZ2DP5UU+1EV0xuMHbChn0rf+djT6q9Kq3pzYjC3nG4GVTo9UcEdyj5KOjuhPuLgjtt/mE7z7fMRM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767920084; c=relaxed/simple; bh=U+ERXgUfSRxYcQMpnmJcQtwAEw2tC+IRhF/3sM+ULAA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=O/eXHs/hmLwQ+Gz5c0S5VpSVc9++6sp7V9aTQHHGq+6ZsqTAbyFxOY9rSEIsssqDaOvl6YNKEzyjgiRkqUZkqSDyuDYBNohpB+r9yapOPnHEC5FO4Jm2F6JrPgGshcxjXYzty3w8OlLljuGQLOtcJPYaepUneyLWhPHVPFxL1yA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=ggX30qBi; arc=none smtp.client-ip=209.85.219.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="ggX30qBi" Received: by mail-qv1-f51.google.com with SMTP id 6a1803df08f44-8907ec50855so42864246d6.3 for ; Thu, 08 Jan 2026 16:54:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1767920082; x=1768524882; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=UAZE/20dBWNTVWUx21XoEWWGeB11q9XckqXbeOgh60E=; b=ggX30qBiAA8FaTfWYEYTd5EVPvdmBPZZ6h4Fzhli80Hv/xquejjv4DN09tgGqAvd1y yAec770oyGkerbMoZxppKuWLybqrpqz3eU4ml/98fCnvuKO36Za7g4bdnyXAM247sZor qSUPOtjBCkrxaXONgBm5oZBIvj4McFWA62b6PeasVvYNnG1QTKH5Gw8uOCMlAyVYNWTU xC/ld2DlyymkCDkMBf4KZ1KzJWmHWTMvTe1xeZujFsL1AASI3zXTwp/PncVOgIeToS9s 1Ei8ETUnTti6nu9Gs281fX3h6wmnHZtyIixVcYSbES5jyy+XBepBS5atgox2y4tDn+HD KQNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767920082; x=1768524882; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=UAZE/20dBWNTVWUx21XoEWWGeB11q9XckqXbeOgh60E=; b=RTMqWFLfoIxnhkpkBbCf6w1eNpYbjjzwKTlPnNgVOcLs2FuD3zBX+igR2OSp37/2ng M3V1P81OP4sXrdsTyyIu+/WInpFsKRpM2b9KAq2jcuXaaB9UeHoe6m2S5ZtIQbsTgh89 cH+pgATZYQ7StjNEisTzEEXRlAtkfad+gQVTSSxT5sZmkcMt5f4saxf0wJN503zTyt1i SlBCiPg7boHtSiMvgF08tduLQdyJe5qJx0vs947E29MgF6hHATQ7ZsG6LIoEhpHfycYu dalWwW6aA5MNpL7Grjm0wJrTIhare4SOwJLdZdR3GmCrN+UJyBEQcqVmxCwxf6fyvjSk t9Fg== X-Forwarded-Encrypted: i=1; AJvYcCUo+kInbxsTIkZZW3aYa/Sw7K9R4oRDdFC2NP6PWVigSGSOJ+u1mOojgNQ4DVxkBfV/781AROND5BKqvKU=@vger.kernel.org X-Gm-Message-State: AOJu0YybzygDYY4qkyix/wb1tgscupolAWZZNYYkpekEs+kqVNAieI/v VFj6iE+ZueXzmNKREIUt2AOqlC5EHu8KWHyrSlsetlgVYf3UzidBxMcJtg9vOcgpHTE= X-Gm-Gg: AY/fxX5dVOBQvPwj2mbqJGYPURNwItRufcak245Oiqmw5b/BHZSqWqk5BdmSEkI7jNd eGDJldSXoXKF3eS1rpaOOKitwTd5UY5uMMosGzYIJR0bqzpnPpp0o0vdIYuNlEmsnXqjo7cuIfW esvewFXEeMq2gYgwj+lJyAI+YFjF1hZx7ZYn4tNGs6cIwQYb5s9IOtJoThPzV1jby7cIwtycvRj eZcO+0T9ILfmWS9W0Pgq2H9cQENOwyMIlvo8HUalqND2by7PiEzM+1df8VEb9Ovbr5eN1S85Mbd vKfaDyav2qv/eDxfR6QgUIbD/ykTp2yRSrjmqjtPAJc493cDE4tlTwY6QF63wyY1kWvRlfTcMT0 Dx0N2ECpCoYI6793AkWYSZEs8Zyq1At7XPY+KlQY8AdFjyJa9eknknXscHh17n+MU0QeQpTh3ej pJ/y48cT9BquAZUvBbn2prTSUh5TEVuLri3WI9dlm13NVEXL2akRcECkEk/iXG95QsnKs= X-Google-Smtp-Source: AGHT+IEZs++vifxK2irZp/20XefsAkmL6blTJ2OewTq/V0KD+K9JOYPvZ0wrg4AeAg9Aq7isQibh6Q== X-Received: by 2002:a05:6214:4509:b0:88a:3c0e:3251 with SMTP id 6a1803df08f44-8908425445emr106914126d6.32.1767920081945; Thu, 08 Jan 2026 16:54:41 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-112-119.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.112.119]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8907726041fsm67934866d6.45.2026.01.08.16.54.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jan 2026 16:54:41 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1ve0m0-00000002vlZ-3hDX; Thu, 08 Jan 2026 20:54:40 -0400 Date: Thu, 8 Jan 2026 20:54:40 -0400 From: Jason Gunthorpe To: David Matlack Cc: Alex Williamson , Alex Mastro , Shuah Khan , Peter Xu , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH] vfio: selftests: Add vfio_dma_mapping_mmio_test Message-ID: <20260109005440.GH545276@ziepe.ca> References: <20260108005406.GA545276@ziepe.ca> <20260108141044.GC545276@ziepe.ca> <20260108084514.1d5e3ee3@shazbot.org> <20260108183339.GF545276@ziepe.ca> <20260109003621.GG545276@ziepe.ca> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Jan 09, 2026 at 12:43:32AM +0000, David Matlack wrote: > On 2026-01-08 08:36 PM, Jason Gunthorpe wrote: > > On Thu, Jan 08, 2026 at 09:29:29PM +0000, David Matlack wrote: > > > On 2026-01-08 02:33 PM, Jason Gunthorpe wrote: > > > > On Thu, Jan 08, 2026 at 10:24:19AM -0800, David Matlack wrote: > > > > > > > Oh, I was thinking about a compatability only flow only in the type 1 > > > > > > > emulation that internally magically converts a VMA to a dmabuf, but I > > > > > > > haven't written anything.. It is a bit tricky and the type 1 emulation > > > > > > > has not been as popular as I expected?? > > > > > > > > > > > > In part because of this gap, I'd guess. Thanks, > > > > > > > > > > Lack of huge mappings in the IOMMU when using VFIO_TYPE1_IOMMU is > > > > > another gap I'm aware of. > > > > > vfio_dma_mapping_test.vfio_type1_iommu_anonymous_hugetlb_1gb.dma_map_unmap > > > > > fails when IOMMUFD_VFIO_CONTAINER is enabled. > > > > > > > > What is this? I'm not aware of it.. > > > > > > It's one of the test cases within > > > tools/testing/selftests/vfio/vfio_dma_mapping_test.c. > > > > > > Here's the output when running with CONFIG_IOMMUFD_VFIO_CONTAINER=y: > > > > > > # RUN vfio_dma_mapping_test.vfio_type1_iommu_anonymous_hugetlb_1gb.dma_map_unmap ... > > > Mapped HVA 0x7f0480000000 (size 0x40000000) at IOVA 0x0 > > > Searching for IOVA 0x0 in /sys/kernel/debug/iommu/intel/0000:6a:01.0/domain_translation_struct > > > Found IOMMU mappings for IOVA 0x0: > > > PGD: 0x0000000203475027 > > > P4D: 0x0000000203476027 > > > PUD: 0x0000000203477027 > > > PMD: 0x00000001e7562027 > > > PTE: 0x00000041c0000067 > > > # tools/testing/selftests/vfio/vfio_dma_mapping_test.c:188:dma_map_unmap:Expected 0 (0) == mapping.pte (282394099815) > > > # dma_map_unmap: Test terminated by assertion > > > # FAIL vfio_dma_mapping_test.vfio_type1_iommu_anonymous_hugetlb_1gb.dma_map_unmap > > > > I can't think of any reason this would fail, I think your tests have > > found a real bug?? Can you check into it, what kernel call fails and > > where does the kernel code come from? > > Oh I thought it was by design. This code in iommufd_vfio_set_iommu(): > > /* > * The difference between TYPE1 and TYPE1v2 is the ability to unmap in > * the middle of mapped ranges. This is complicated by huge page support > * which creates single large IOPTEs that cannot be split by the iommu > * driver. TYPE1 is very old at this point and likely nothing uses it, > * however it is simple enough to emulate by simply disabling the > * problematic large IOPTEs. Then we can safely unmap within any range. > */ > if (type == VFIO_TYPE1_IOMMU) > rc = iopt_disable_large_pages(&ioas->iopt); > > git-blame says some guy named Jason Gunthorpe wrote it :P Er, maybe I mis understood the output then? This is not a "failure" though, the map succeeded and gave a small page mapping. This is not reflecting a bug in iommufd but a bug in the TYPE1 support in VFIO itself because it definitely cannot maintain the required unmap anywhere semantic if it mapped in a 1G huge page like this. Basically, if you are mapping with TYPE1 mode then this should be triggered: if (!strcmp(variant->iommu_mode, "iommufd_compat_type1")) mapping_size = SZ_4K; And VFIO should be the one to fail, not iommufd. If you really want to test TYPE1 you need to test what makes it unique, which is that you can map any VMA and then unmap any slice of it. Including within what should otherwise be a 1G page. But I doubt anyone cares enough to fix this, so just exclude VFIO_TYPE1_IOMMU from this test? Jason