From: Gregory Price <gourry@gourry.net>
To: "Zhijian Li (Fujitsu)" <lizhijian@fujitsu.com>
Cc: Huaisheng Ye <huaisheng.ye@intel.com>,
"Jonathan.Cameron@huawei.com" <Jonathan.Cameron@huawei.com>,
"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"dave.jiang@intel.com" <dave.jiang@intel.com>,
"pei.p.jia@intel.com" <pei.p.jia@intel.com>,
"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>
Subject: Re: [RFC PATCH] cxl/core: reenable Mem_Enable bit of DVSEC control when RR decodes outside platform ranges
Date: Wed, 9 Apr 2025 09:13:51 -0500 [thread overview]
Message-ID: <Z_aAnzqR-UP9rmIY@gourry-fedora-PF4VCD3F> (raw)
In-Reply-To: <02fbb2a7-3973-4c7f-8b7d-cfabbb379467@fujitsu.com>
On Mon, Apr 07, 2025 at 08:31:13AM +0000, Zhijian Li (Fujitsu) wrote:
> [1] https://lore.kernel.org/linux-cxl/20240409075846.85370-1-lizhijian@fujitsu.com/
After looking at this, I see why this hasn't been fixed in QEMU.
Basically QEMU doesn't implement the right reset mechanism.
ct3_reset calls
cxl_component_register_init_common()
ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_GLOBAL_CONTROL,
HDM_DECODER_ENABLE, 0)
But it never resets MEM_ENABLE in the dvsecs.
I'm not sure it's sane for Linux to be trying to handle hardware that
doesn't itself reset correctly - and doing this fix just for QEMU seems
a bit too far.
The correct fix here is building an accessor for the existing CXL dvsecs
and updating it during ct3_reset.
~Gregory
next prev parent reply other threads:[~2025-04-09 14:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-06 11:27 [RFC PATCH] cxl/core: reenable Mem_Enable bit of DVSEC control when RR decodes outside platform ranges Huaisheng Ye
2025-04-07 8:31 ` Zhijian Li (Fujitsu)
2025-04-09 3:51 ` Ye, Huaisheng
2025-04-09 14:13 ` Gregory Price [this message]
2025-04-09 15:13 ` Dave Jiang
2025-04-15 16:21 ` Jonathan Cameron
2025-04-08 3:22 ` Gregory Price
2025-04-09 3:48 ` Ye, Huaisheng
2025-04-09 14:01 ` Gregory Price
2025-04-10 7:12 ` Ye, Huaisheng
2025-04-15 16:30 ` Jonathan Cameron
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