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 6E6832EB871; Thu, 4 Sep 2025 12:28:58 +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=1756988938; cv=none; b=UaHC3sn8vHV7RHEKXkmYMw7bZRVjMek8JiLZdq/uU2K0eyWcQxpcyRCdIJ0dGKtcbxeYC7TiuRVjUMUcwP+zfbmn544I5n9j49U5wO3h1Uj7FGHgkRABdgkTr2S5ha0L5vfnzfvBloMP8pYgfFNEbsorz2KVN2F+XLgZP55hLHE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756988938; c=relaxed/simple; bh=Hxa1aMEFLaONCF/Z4hf/tCWlMBHGKFUBQC+vB4D1feU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TDf1/bBNyT/ST4mI4Tpq5rBNRJLd8nGhERYxtkeTuO1uOcFoO/TNPE8//RJwFMHSdVSquMcpQ1KmrGirecMfs70FVFAOEnDk8tJPIIpcdFDwFSYdYM57ST7SIo8Css+icq3lqyLMcJ5S8HLXPSw8lZfoCLunOV1gTwqyAmLfnW8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rf8A+Q/h; 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="rf8A+Q/h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C19FC4CEF4; Thu, 4 Sep 2025 12:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756988938; bh=Hxa1aMEFLaONCF/Z4hf/tCWlMBHGKFUBQC+vB4D1feU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rf8A+Q/hq0H5TXLZc6VFkn0MLRiZETdXvxGb+qtgOIXgW1VpXpSFhc4EcN0B/Bkep z7sLJcwhIfZBGN5SmE77IaO/fqeexboclGtAt5EWykQKtR+RLhs/PdtodgJI2dm3Tt j3zKA0jRHNHnjpeLs445vMJNcsEWoa12ZNrPozUxocKPDZBE+xf0omZlSXdhfVsK6r aQz5IuyUBumMOMMaI8ahc9GDv7GmDZfry88DeFDoGJZZrajQtpsRuvVAt5CsFdTPMU 4YlRmGmq4TKnGmSvmmTuntQ4vf8ctasLdaIkoLzs/lx8IvnXbsbpD1oKU912OI1Hoy m3349uZv5lflw== Date: Thu, 4 Sep 2025 14:28:53 +0200 From: Niklas Cassel To: Damien Le Moal Cc: Marek Vasut , linux-pci@vger.kernel.org, Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Bjorn Helgaas , Frank Li , Kishon Vijay Abraham I , Manivannan Sadhasivam , Wang Jiang , linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Jerome Brunet Subject: Re: [PATCH] PCI: endpoint: pci-epf-test: Limit PCIe BAR size for fixed BARs Message-ID: References: <20250904023753.494147-1-marek.vasut+renesas@mailbox.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Sep 04, 2025 at 11:40:15AM +0900, Damien Le Moal wrote: > On 9/4/25 11:37 AM, Marek Vasut wrote: > > Currently, the test allocates BAR sizes according to fixed table > > bar_size[] = { 512, 512, 1024, 16384, 131072, 1048576 } . This > > does not work with controllers which have fixed size BARs, like > > Renesas R-Car V4H PCIe controller, which has BAR4 size limited > > to 256 Bytes, which is much less than 131072 currently requested > > by this test. > > > > Adjust the test such, that in case a fixed size BAR is detected > > on a controller, minimum of requested size and fixed size BAR > > size is used during the test instead. > > > > This helps with test failures reported as follows: > > " > > pci_epf_test pci_epf_test.0: requested BAR size is larger than fixed size > > pci_epf_test pci_epf_test.0: Failed to allocate space for BAR4 > > " > > > > Signed-off-by: Marek Vasut > > --- > > Cc: "Krzysztof Wilczyński" > > Cc: Bjorn Helgaas > > Cc: Damien Le Moal > > Cc: Frank Li > > Cc: Kishon Vijay Abraham I > > Cc: Manivannan Sadhasivam > > Cc: Niklas Cassel > > Cc: Wang Jiang > > Cc: linux-kernel@vger.kernel.org > > Cc: linux-pci@vger.kernel.org > > Cc: linux-renesas-soc@vger.kernel.org > > --- > > drivers/pci/endpoint/functions/pci-epf-test.c | 11 +++++++++-- > > 1 file changed, 9 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > > index e091193bd8a8a..d9c950d4c9a9e 100644 > > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > > @@ -1022,7 +1022,8 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf) > > enum pci_barno test_reg_bar = epf_test->test_reg_bar; > > enum pci_barno bar; > > const struct pci_epc_features *epc_features = epf_test->epc_features; > > - size_t test_reg_size; > > + size_t test_reg_size, test_bar_size; > > + u64 bar_fixed_size; > > > > test_reg_bar_size = ALIGN(sizeof(struct pci_epf_test_reg), 128); > > > > @@ -1050,7 +1051,13 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf) > > if (bar == test_reg_bar) > > continue; > > > > - base = pci_epf_alloc_space(epf, bar_size[bar], bar, > > + test_bar_size = bar_size[bar]; > > + > > + bar_fixed_size = epc_features->bar[bar].fixed_size; > > + if (epc_features->bar[bar].type == BAR_FIXED && bar_fixed_size) > > + test_bar_size = min(bar_size[bar], bar_fixed_size); > > I think this can be simplified to: > > if (epc_features->bar[bar].type == BAR_FIXED) > test_bar_size = epc_features->bar[bar].fixed_size; > else > test_bar_size = bar_size[bar]; +1 > > because if the bar type is BAR_FIXED, then the size of the bar can only be its > fixed size. Correct, see: f015b53d634a ("PCI: endpoint: Add size check for fixed size BARs in pci_epc_set_bar()") Actually, Jerome Brunet was also using this weird Renesas R-Car V4H PCIe controller where BAR4 is a really small fixed-size BAR. (Even smaller than the iATU minimum alignment requirement for that same controller.) See: 793908d60b87 ("PCI: endpoint: Retain fixed-size BAR size as well as aligned size") But he only appears to have used the vntb epf driver. Jerome, I suppose that you never ran with the pci-epf-test driver? pci_epf_alloc_space() works like this: If the user requests a BAR size that is smaller than the fixed-size BAR, it will allocate space matching the fixed-size. As in most cases, having a BAR larger than needed by an EPF driver is still acceptable. However, if the user requests a size larger than the fixed-size BAR, as in your case, we will return an error, as we cannot fulfill the user's request. I don't see any alternative other than your/Damien's proposal above. Unfortunately, all EPF drivers would probably need this same change. Kind regards, Niklas