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Message-ID: <7d8958a5-01cf-428d-bc40-efc06d1be8fe@rivosinc.com>
Date:   Wed, 11 Oct 2023 15:01:55 +0200
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Subject: Re: [PATCH] riscv, qemu_fw_cfg: Add support for RISC-V architecture
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To:     =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>,
        Gabriel Somlo <somlo@cmu.edu>,
        "Michael S. Tsirkin" <mst@redhat.com>, qemu-devel@nongnu.org
Cc:     =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@rivosinc.com>,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
References: <20231011114721.193732-1-bjorn@kernel.org>
From:   =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= <cleger@rivosinc.com>
In-Reply-To: <20231011114721.193732-1-bjorn@kernel.org>
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Precedence: bulk


Hi Björn,

On 11/10/2023 13:47, Björn Töpel wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
> 
> Qemu fw_cfg support was missing for RISC-V, which made it hard to do
> proper vmcore dumps from qemu.
> 
> Add the missing RISC-V arch-defines.
> 
> You can now do vmcore dumps from qemu. Add "-device vmcoreinfo" to the
> qemu command-line. From the qemu montior:

small typo here: monitor

>   (qemu) dump-guest-memory vmcore
> 
> The vmcore can now be used, e.g., with the "crash" utility.
> 
> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
> ---
>  drivers/firmware/Kconfig       | 2 +-
>  drivers/firmware/qemu_fw_cfg.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index b59e3041fd62..f05ff56629b3 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -155,7 +155,7 @@ config RASPBERRYPI_FIRMWARE
>  
>  config FW_CFG_SYSFS
>  	tristate "QEMU fw_cfg device support in sysfs"
> -	depends on SYSFS && (ARM || ARM64 || PARISC || PPC_PMAC || SPARC || X86)
> +	depends on SYSFS && (ARM || ARM64 || PARISC || PPC_PMAC || RISCV || SPARC || X86)
>  	depends on HAS_IOPORT_MAP
>  	default n
>  	help
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index a69399a6b7c0..1448f61173b3 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -211,7 +211,7 @@ static void fw_cfg_io_cleanup(void)
>  
>  /* arch-specific ctrl & data register offsets are not available in ACPI, DT */
>  #if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CFG_DATA_OFF))
> -# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
> +# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64) || defined(CONFIG_RISCV))
>  #  define FW_CFG_CTRL_OFF 0x08
>  #  define FW_CFG_DATA_OFF 0x00
>  #  define FW_CFG_DMA_OFF 0x10
> 
> base-commit: 1c8b86a3799f7e5be903c3f49fcdaee29fd385b5

I didn't know that qemu could generate vmcore files. BTW, whenever I
don't have 'crash' at hand, I often use them with gdb and vmlinux-gdb.py
debugging scripts. Anyway, works as expected:

Tested-by: Clément Léger <cleger@rivosinc.com>

Clément