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 00E9C1DFCE; Wed, 9 Jul 2025 14:39:53 +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=1752071994; cv=none; b=uf+ZZ3BnH7mpFKYJT9grW7fBdG08q3pAR/ON27TdezzDcaYdIeD+FgpTbOPfmeDUjQdVjzTZqjIf/J4RLNHfLrMNy6pI3FzqpwHP6VjyGYFFPYRuYwk/aymhnGf0VI+va6NclaK7mub9HjZ70vELRL4PTJBfxhlERSIB2kEsse8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752071994; c=relaxed/simple; bh=l54NsMtGhXxYp8oNZatWnK+eHuDMVoDSH6p0tUsecMg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VCh3vbkm7SrTb8QTsXDfnx0+grLb8tv8Ci2sZJ1k5bM13jCV1opql6GpIJLzowgMVXzkHa/DD+AoHJfD6VDq+3MdCHyfZ5TUdXEdnWIi4XHTKraTnac8Za6A+ffo7VjA3f9VHR0vVepdaYXKvw8R6OaGdYnLO23tQrhfqGIyR+A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QVz7dgS/; 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="QVz7dgS/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76CCEC4CEF1; Wed, 9 Jul 2025 14:39:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752071993; bh=l54NsMtGhXxYp8oNZatWnK+eHuDMVoDSH6p0tUsecMg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=QVz7dgS/RGY5kzgDrulXPsE8IfCA2EUYdik/oFLipbxtSfFdqdaEo8lHOP0971E/L hkA4UU/gAbgdhNmplCQ1qXcsXmnleMVGIBQAJSEV9IHFfa4yo25lFdQCb1SqL3m58w Sximjdged91fuHAb6sqR6cQAePtO8gyyP0F+KgU9VINYXOlxSC4tc2S3HuybDmncYH 3ohbc5FRx5bhdNs1rsNEb4FbsOvjeexTBrh8+hC96UhAhbI2ZlwIC9+UTAEFKz8AKW cq1dgXKGCXLBFV1H1vsAXmp2yU0V4J/JhCT32HRrhkn1fCDTaWGsY1Xd6hbGeeyBQ6 Dz3tUJguyuumw== Message-ID: <5800c426-95fd-4a81-b979-c0bc2bc293dd@kernel.org> Date: Wed, 9 Jul 2025 16:39:49 +0200 Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] efi: add ovmf debug log driver To: Gerd Hoffmann Cc: linux-efi@vger.kernel.org, Ard Biesheuvel , open list References: <20250708125624.734132-1-kraxel@redhat.com> <6edfa099-ab0c-41f6-89ea-0fd67666dd05@kernel.org> <2mn65slwkwmjpeilma2isw7zgabdmda4rhpqjiutwdwqno2wrh@zghymlce2fiy> <8621135e-445a-42dd-89e0-bf8fc3e2b6b7@kernel.org> <4cix3k4h32wozt3nxic5un7jyzfjrmqmzbzmtr3ivw5b2bz363@mw6bke7w4oaq> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 09/07/2025 16:31, Gerd Hoffmann wrote: > On Wed, Jul 09, 2025 at 04:20:49PM +0200, Krzysztof Kozlowski wrote: >> On 09/07/2025 16:17, Gerd Hoffmann wrote: >>> On Wed, Jul 09, 2025 at 03:58:58PM +0200, Krzysztof Kozlowski wrote: >>>> On 08/07/2025 14:56, Gerd Hoffmann wrote: >>>>> +MODULE_DESCRIPTION("OVMF debug log"); >>>>> +MODULE_AUTHOR("Gerd Hoffmann "); >>>>> +MODULE_LICENSE("GPL"); >>>>> +MODULE_ALIAS("platform:ovmf_debug_log"); >>>>> diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig >>>>> index db8c5c03d3a2..ac0a03ec3452 100644 >>>>> --- a/drivers/firmware/efi/Kconfig >>>>> +++ b/drivers/firmware/efi/Kconfig >>>>> @@ -263,6 +263,14 @@ config EFI_COCO_SECRET >>>>> virt/coco/efi_secret module to access the secrets, which in turn >>>>> allows userspace programs to access the injected secrets. >>>>> >>>>> +config OVMF_DEBUG_LOG >>>>> + tristate "Expose OVMF firmware debug log via sysfs" >>>>> + depends on EFI >>>>> + help >>>>> + Recent OVMF versions (edk2-stable202508 + newer) can write >>>>> + their debug log to a memory buffer. This driver exposes the >>>>> + log content via sysfs (/sys/firmware/efi/ovmf_debug_log). >>>> >>>> Where did you document new ABI? >>> >>> The log buffer header struct is documented in the header file for the >>> edk2 code: >>> https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Library/MemDebugLogLib.h >> >> You added a new sysfs interface. I meant documentation for this. > > The sysfs file contains the log and you can simply use > 'cat /sys/firmware/efi/ovmf_debug_log' to read it. Don't explain how it works to me. I did not ask how it works. I asked where is the new ABI documented? Best regards, Krzysztof