Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756833AbbLQQKX (ORCPT ); Thu, 17 Dec 2015 11:10:23 -0500 Received: from SMTP.ANDREW.CMU.EDU ([128.2.157.39]:59992 "EHLO smtp.andrew.cmu.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756811AbbLQQKQ (ORCPT ); Thu, 17 Dec 2015 11:10:16 -0500 Date: Thu, 17 Dec 2015 11:09:23 -0500 From: "Gabriel L. Somlo" To: gregkh@linuxfoundation.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, arnd@arndb.de, lersek@redhat.com, ralf@linux-mips.org, rmk+kernel@arm.linux.org.uk, eric@anholt.net, hanjun.guo@linaro.org, zajec5@gmail.com, sudeep.holla@arm.com, agross@codeaurora.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Cc: qemu-devel@nongnu.org, jordan.l.justen@intel.com, mst@redhat.com, peter.maydell@linaro.org, leif.lindholm@linaro.org, ard.biesheuvel@linaro.org, pbonzini@redhat.com, kraxel@redhat.com, luto@amacapital.net, stefanha@gmail.com, revol@free.fr, matt@codeblueprint.co.uk Subject: Re: [PATCH v6 0/4] SysFS driver for QEMU fw_cfg device Message-ID: <20151217160923.GI19448@HEDWIG.INI.CMU.EDU> References: <1449242946-12062-1-git-send-email-somlo@cmu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1449242946-12062-1-git-send-email-somlo@cmu.edu> X-Clacks-Overhead: GNU Terry Pratchett User-Agent: Mutt/1.5.24 (2015-08-30) X-PMX-Version: 6.0.3.2322014, Antispam-Engine: 2.7.2.2107409, Antispam-Data: 2015.12.17.160015 X-SMTP-Spam-Clean: 8% ( MULTIPLE_RCPTS 0.1, HTML_00_01 0.05, HTML_00_10 0.05, DATE_TZ_NA 0, FROM_EDU_TLD 0, NO_URI_HTTPS 0, REFERENCES 0, SINGLE_URI_IN_BODY 0, __ANY_URI 0, __BOUNCE_CHALLENGE_SUBJ 0, __BOUNCE_NDR_SUBJ_EXEMPT 0, __CD 0, __CP_URI_IN_BODY 0, __CT 0, __CT_TEXT_PLAIN 0, __FORWARDED_MSG 0, __HAS_FROM 0, __HAS_MSGID 0, __IN_REP_TO 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __MULTIPLE_RCPTS_CC_X2 0, __MULTIPLE_RCPTS_TO_X5 0, __PHISH_SPEAR_STRUCTURE_1 0, __REFERENCES 0, __SANE_MSGID 0, __SINGLE_URI_TEXT 0, __SUBJ_ALPHA_END 0, __SUBJ_ALPHA_NEGATE 0, __TO_MALFORMED_2 0, __TO_NO_NAME 0, __URI_IN_BODY 0, __URI_NO_WWW 0, __URI_NS , __USER_AGENT 0) X-SMTP-Spam-Score: 8% Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7113 Lines: 187 ping ? Also, for the corresponding patch set on the QEMU end of things, ping on http://thread.gmane.org/gmane.comp.emulators.qemu/376321 Thanks, --Gabriel On Fri, Dec 04, 2015 at 10:29:02AM -0500, Gabriel L. Somlo wrote: > Allow access to QEMU firmware blobs, passed into the guest VM via > the fw_cfg device, through SysFS entries. Blob meta-data (e.g. name, > size, and fw_cfg key), as well as the raw binary blob data may be > accessed. > > The SysFS access location is /sys/firmware/qemu_fw_cfg/... and was > selected based on overall similarity to the type of information > exposed under /sys/firmware/dmi/entries/... > > New since v5: > > - fixed typos in documentation files (Patches 1/4 and 4/4 > > - printf/scanf type modifier for phys_addr_t now matches > arch-specific width (u32 vs. u64), avoiding compiler warnings. > (tested on i386 with and without PAE, and on armv7hl with and > without lpae -- the latter pair took quite a while on an > emulated QEMU guest :) ) > > Thanks, > --Gabriel > > >New since v4: > > > > Documentation (Patches 1/4 and 4/4) now points to the authoritative > > file in the QEMU source tree for any details related to the "hardware > > interface" of the fw_cfg device; Only details specific to sysfs (1/4) > > and DT (4/4) should stay in the kernel docs. > > > >>New (since v3): > >> > >> Patch 1/4: Device probing now works with either ACPI, DT, or > >> optionally by manually specifying a base, size, and > >> register offsets on the command line. This way, all > >> architectures offering fw_cfg can be supported, although > >> x86 and ARM get *automatic* support via ACPI and/or DT. > >> > >> HUGE thanks to Laszlo Ersek for > >> pointing out drivers/virtio/virtio_mmio.c, as an example > >> on how to pull this off !!! > >> > >> Stefan: I saw Marc's DMA patches to fw_cfg. Since only > >> x86 and ARM will support it starting with QEMU 2.5, and > >> since I expect to get lots of otherwise interesting (but > >> otherwise orthogonal) feedback on this series, I'd like > >> to stick with ioread8() across the board for now. We can > >> always patch in DMA support in a backward compatible way > >> later, once this series gets (hopefully) accepted :) > >> > >> Patch 2/4: (was 3/4 in v3): unchanged. Exports kset_find_obj() so > >> modules can call it. > >> > >> Patch 3/4: (was 4/4 in v3): rebased, but otherwise the same. > >> Essentially, creates a "human readable" directory > >> hierarchy from "path-like" tokens making up fw_cfg > >> blob names. I'm not really sure there's a way to make > >> this happen via udev rules, but I have at least one > >> potential use case for doing it *before* udev becomes > >> available (cc: Andy Lutomirski ), > >> so I'd be happy to leave this functionality in the > >> kernel module. See further below for an illustration > >> of this. > >> > >> Patch 4/4: Updates the existing ARM DT documentation for fw_cfg, > >> mainly by pointing at the more comprehensive document > >> introduced with Patch 1/4 for details on the fw_cfg > >> device interface, leaving only the specific ARM/DT > >> address/size node information in place. > >> > >>> In addition to the "by_key" blob listing, e.g.: > >>> > >>> $ tree /sys/firmware/qemu_fw_cfg/ > >>> /sys/firmware/qemu_fw_cfg/ > >>> |-- by_key > >>> | |-- 32 > >>> | | |-- key > >>> | | |-- name ("etc/boot-fail-wait") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 33 > >>> | | |-- key > >>> | | |-- name ("etc/smbios/smbios-tables") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 34 > >>> | | |-- key > >>> | | |-- name ("etc/smbios/smbios-anchor") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 35 > >>> | | |-- key > >>> | | |-- name ("etc/e820") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 36 > >>> | | |-- key > >>> | | |-- name ("genroms/kvmvapic.bin") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 37 > >>> | | |-- key > >>> | | |-- name ("etc/system-states") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 38 > >>> | | |-- key > >>> | | |-- name ("etc/acpi/tables") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 39 > >>> | | |-- key > >>> | | |-- name ("etc/table-loader") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 40 > >>> | | |-- key > >>> | | |-- name ("etc/tpm/log") > >>> | | |-- raw > >>> | | `-- size > >>> | |-- 41 > >>> | | |-- key > >>> | | |-- name ("etc/acpi/rsdp") > >>> | | |-- raw > >>> | | `-- size > >>> | `-- 42 > >>> | |-- key > >>> | |-- name ("bootorder") > >>> | |-- raw > >>> | `-- size > >>> | > >>> ... > >>> > >>> Patch 3/4 also gets us a "human readable" "by_name" listing, like so: > >>> > >>> ... > >>> |-- by_name > >>> | |-- bootorder -> ../by_key/42 > >>> | |-- etc > >>> | | |-- acpi > >>> | | | |-- rsdp -> ../../../by_key/41 > >>> | | | `-- tables -> ../../../by_key/38 > >>> | | |-- boot-fail-wait -> ../../by_key/32 > >>> | | |-- e820 -> ../../by_key/35 > >>> | | |-- smbios > >>> | | | |-- smbios-anchor -> ../../../by_key/34 > >>> | | | `-- smbios-tables -> ../../../by_key/33 > >>> | | |-- system-states -> ../../by_key/37 > >>> | | |-- table-loader -> ../../by_key/39 > >>> | | `-- tpm > >>> | | `-- log -> ../../../by_key/40 > >>> | `-- genroms > >>> | `-- kvmvapic.bin -> ../../by_key/36 > >>> `-- rev > > Gabriel Somlo (4): > firmware: introduce sysfs driver for QEMU's fw_cfg device > kobject: export kset_find_obj() for module use > firmware: create directory hierarchy for sysfs fw_cfg entries > devicetree: update documentation for fw_cfg ARM bindings > > .../ABI/testing/sysfs-firmware-qemu_fw_cfg | 100 +++ > Documentation/devicetree/bindings/arm/fw-cfg.txt | 38 +- > drivers/firmware/Kconfig | 19 + > drivers/firmware/Makefile | 1 + > drivers/firmware/qemu_fw_cfg.c | 735 +++++++++++++++++++++ > lib/kobject.c | 1 + > 6 files changed, 858 insertions(+), 36 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg > create mode 100644 drivers/firmware/qemu_fw_cfg.c > > -- > 2.4.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/