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 98D532E3B1E; Wed, 9 Jul 2025 14:40:38 +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=1752072038; cv=none; b=TwLOmUa2b2xQM2RhlegjQTKYmCh7YIgnsjsALveJsqoyZW0OkgLX6Gm0PgOXEg/PS9cg2A7G+T0fsWCswwI+QyZ82d3QVoeZtlqoqZyHL51FN8b5+qtazhM534Pt4oM8CL8viUHzuRx+MSIDe8pBRCr7Di4ARglgrMd9pFjRZ/0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752072038; c=relaxed/simple; bh=4gltpAo6G2z6Uhvda05MhKbl9p35Vf6wHr1KiUVlyP4=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=THUcBBUGJuEv6RqZsKw8jWy4GRZL4cO5qCSNm31QWW+l94NSxwYaH9hPuiG5SLRDNIiqrPgSmYQfbuOIQiLRrLkTUV3cqwMoHEMuvvtnCSV1CUVhNpIura72RVks9S0X3sNwUkbCY4khmouA0jXkIlNyN3fyAqt08Sf2fzh1MgE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZUX+twZ4; 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="ZUX+twZ4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05E68C4CEEF; Wed, 9 Jul 2025 14:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752072038; bh=4gltpAo6G2z6Uhvda05MhKbl9p35Vf6wHr1KiUVlyP4=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=ZUX+twZ4+jBAoRIbfBQCT00xQ5+ZsirmbzJun1ukTD3QAdiA6hDRfv6zD4durLKoP lvG0zq/8mCTPsYPkQY839i2JSeyzaYTJlpNiKcDF4YKmpnm6eXf/Mx3qCxGI4APTAh fhNKrq0HWZRMqZTUOGevD2ZEcc56hjNiHQ4H+4WdXBjaQv3OuhT/HqEyh2S04NZM6k P3mNWKvufwKJBKWlL2VlL41ZCMz35GxdR4qIvEuXxfZDffhzck9ww0zBQqu6B+gziJ RpEa1cTsFcW4zKN8guGq84wsRlfHfApPHxJ/GB6u/EQmwHYi6I3nu7/mUkVFgI92rK CpMyt6CIqOiqg== Message-ID: <73a18fe6-daef-4035-abb2-67db2c5619e2@kernel.org> Date: Wed, 9 Jul 2025 16:40:35 +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 From: Krzysztof Kozlowski 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> <5800c426-95fd-4a81-b979-c0bc2bc293dd@kernel.org> Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 09/07/2025 16:39, Krzysztof Kozlowski wrote: > 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? ... and if answer is nowhere, then that's the problem. You need to document new ABI - see docs in kernel sources. Best regards, Krzysztof