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 44FDA18859B; Wed, 23 Apr 2025 13:34:16 +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=1745415260; cv=none; b=JNWwZJ09OJdGxp5bVx8MQRdV1CDWxp/QTBrvACsXdCeJSB80q0JL0v9dTZa6SkDtsVmfQAoy08CbXumTns6xFjspsCMElWZ9ynlBG8GzawvI0QVF/yv5LE0WZyaAoJemOeMpFqPF0kNka60hhoOwsO5a47KQUNMP9l4B2k3DlSQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745415260; c=relaxed/simple; bh=ueUfGPiRe8CWFt/O1EQf5z5vxeIPa9k232U3/o+JgxE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WkqT5H0rWKXLwb2UbDuZKkUv5pURBQupSXFKWzadlCvyT4CzCy7PaasKyYhRw67rh3PLvyDLG+9nNPyG9NlYgx8m06BvkHxEJSp7+/v44qL7eCrm9WV22SGhjJq0QqeGRcA7WQ3xeAL9jMhV+eJrFx/AMY9R/ah3c+mswGFI1Sw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kBTK9IV7; 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="kBTK9IV7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C41EC4CEE2; Wed, 23 Apr 2025 13:34:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745415256; bh=ueUfGPiRe8CWFt/O1EQf5z5vxeIPa9k232U3/o+JgxE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kBTK9IV7mbg1F9P+I6yRAqsmiDAfQ8VwP0UPACt3x4Q58QN21dpx8SfxQMOhJ/Oae u3bpfrgDsBMFmm//YSdnlxsTtAYc3YMXpsP1CbRTU468E0IVifsKRyhlql+rxVydF2 BAtOe4q+finogOh41KWxU3JrHBvKtzKrgny2a71XD0g+yXLSLoY7TKp4VxM4+ucMgg 7BDeSUIRQWhSsq//ZxZ8mDR199dZVnGpBfgXV+39fMFzf2gMHvWUf2T7TRcU4VvmoC AuBFNONti3ADtZPvbU/gE7qsBUBP4rnH/pqvXaytDr6ai16jJn74lR9d6+FHfpU/j8 bG0i9iXLi3Fiw== Date: Wed, 23 Apr 2025 15:34:09 +0200 From: Niklas Cassel To: Jerome Brunet Cc: Manivannan Sadhasivam , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Kishon Vijay Abraham I , Bjorn Helgaas , Lorenzo Pieralisi , Jon Mason , Dave Jiang , Allen Hubbe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Marek Vasut , Yoshihiro Shimoda , Yuya Hamamachi , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ntb@lists.linux.dev, linux-nvme@lists.infradead.org Subject: Re: [PATCH v4 1/2] PCI: endpoint: improve fixed_size bar handling when allocating space Message-ID: References: <20250422-pci-ep-size-alignment-v4-0-6bd58443fee9@baylibre.com> <20250422-pci-ep-size-alignment-v4-1-6bd58443fee9@baylibre.com> 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: <20250422-pci-ep-size-alignment-v4-1-6bd58443fee9@baylibre.com> On Tue, Apr 22, 2025 at 04:54:19PM +0200, Jerome Brunet wrote: > When trying to allocate space for an endpoint function on a BAR with a > fixed size, the size saved in the 'struct pci_epf_bar' should be the fixed > size. This is expected by pci_epc_set_bar(). > > However, if the fixed_size is smaller that the alignment, the size saved > in the 'struct pci_epf_bar' matches the alignment and it is a problem for > pci_epc_set_bar(). > > To solve this, continue to allocate space that match the iATU alignment > requirement, saving it as .aligned_size, then save the size that matches > what is present in the BAR. > > Fixes: 2a9a801620ef ("PCI: endpoint: Add support to specify alignment for buffers allocated to BARs") > Signed-off-by: Jerome Brunet > --- > drivers/pci/endpoint/pci-epf-core.c | 21 ++++++++++++++------- > include/linux/pci-epf.h | 3 +++ > 2 files changed, 17 insertions(+), 7 deletions(-) > > diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c > index 394395c7f8decfa2010469655a4bd58a002993fd..982db6c1fbe77653f6a74a31df5c4e997507d2d8 100644 > --- a/drivers/pci/endpoint/pci-epf-core.c > +++ b/drivers/pci/endpoint/pci-epf-core.c > @@ -236,12 +236,13 @@ void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar, > } > > dev = epc->dev.parent; > - dma_free_coherent(dev, epf_bar[bar].size, addr, > + dma_free_coherent(dev, epf_bar[bar].aligned_size, addr, > epf_bar[bar].phys_addr); > > epf_bar[bar].phys_addr = 0; > epf_bar[bar].addr = NULL; > epf_bar[bar].size = 0; > + epf_bar[bar].aligned_size = 0; > epf_bar[bar].barno = 0; > epf_bar[bar].flags = 0; > } > @@ -264,7 +265,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, > enum pci_epc_interface_type type) > { > u64 bar_fixed_size = epc_features->bar[bar].fixed_size; > - size_t align = epc_features->align; > + size_t aligned_size, align = epc_features->align; > struct pci_epf_bar *epf_bar; > dma_addr_t phys_addr; > struct pci_epc *epc; > @@ -285,12 +286,17 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, > return NULL; > } > size = bar_fixed_size; > + } else { > + /* BAR size must be power of two */ > + size = roundup_pow_of_two(size); > } > > - if (align) > - size = ALIGN(size, align); > - else > - size = roundup_pow_of_two(size); > + /* > + * Allocate enough memory to accommodate the iATU alignment requirement. > + * In most cases, this will be the same as .size but it might be different > + * if, for example, the fixed size of a BAR is smaller than align. > + */ > + aligned_size = align ? ALIGN(size, align) : size; > > if (type == PRIMARY_INTERFACE) { > epc = epf->epc; > @@ -301,7 +307,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, > } > > dev = epc->dev.parent; > - space = dma_alloc_coherent(dev, size, &phys_addr, GFP_KERNEL); > + space = dma_alloc_coherent(dev, aligned_size, &phys_addr, GFP_KERNEL); > if (!space) { > dev_err(dev, "failed to allocate mem space\n"); > return NULL; > @@ -310,6 +316,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, > epf_bar[bar].phys_addr = phys_addr; > epf_bar[bar].addr = space; > epf_bar[bar].size = size; > + epf_bar[bar].aligned_size = aligned_size; > epf_bar[bar].barno = bar; > if (upper_32_bits(size) || epc_features->bar[bar].only_64bit) > epf_bar[bar].flags |= PCI_BASE_ADDRESS_MEM_TYPE_64; > diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h > index 879d19cebd4fc6d8df9d724e3a52fa7fbd61e535..23b0878c2665db1c21e6e83543c33149ab1e0009 100644 > --- a/include/linux/pci-epf.h > +++ b/include/linux/pci-epf.h > @@ -114,6 +114,8 @@ struct pci_epf_driver { > * @phys_addr: physical address that should be mapped to the BAR > * @addr: virtual address corresponding to the @phys_addr > * @size: the size of the address space present in BAR > + * @aligned_size: the size actually allocated to accommodate the iATU alignment > + * requirement. Nit: Since none of the other lines end with a full stop. Perhaps add one for all lines, or continue not having it for all lines. Regardless: Reviewed-by: Niklas Cassel