From: Kiryl Shutsemau <kas@kernel.org>
To: Zhenzhong Duan <zhenzhong.duan@intel.com>
Cc: marcandre.lureau@redhat.com, david@kernel.org,
rick.p.edgecombe@intel.com, prsampat@amd.com,
pbonzini@redhat.com, mst@redhat.com, peterx@redhat.com,
chenyi.qiang@intel.com, elena.reshetova@intel.com,
michael.roth@amd.com, ackerleytng@google.com,
linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev,
virtualization@lists.linux.dev, x86@kernel.org,
yilun.xu@intel.com, xiaoyao.li@intel.com, chao.p.peng@intel.com
Subject: Re: [RFCv2 PATCH 1/6] efi/unaccepted: Support hotplug memory in unaccepted bitmap via SRAT
Date: Wed, 24 Jun 2026 13:25:46 +0100 [thread overview]
Message-ID: <ajvLaBs62bDoxC3W@thinkstation> (raw)
In-Reply-To: <20260623101739.79695-2-zhenzhong.duan@intel.com>
On Tue, Jun 23, 2026 at 06:17:32AM -0400, Zhenzhong Duan wrote:
> Currently, allocate_unaccepted_bitmap() only scans the initial EFI
> boot memory map. This misses hotpluggable ranges described in the
> ACPI SRAT. Without early tracking, hotplug pages are accessed without
> acceptance and this triggers guest crash.
>
> Introduce a lightweight ACPI SRAT parser to scan these regions early.
> If a region has both ACPI_SRAT_MEM_ENABLED and ACPI_SRAT_MEM_HOT_PLUGGABLE
> flags, expand the tracking boundaries. This avoids pulling in the full
> ACPI subsystem while ensuring the bitmap covers both static memory and
> hotplug memory.
Ugh.. Parsing SRAT there is ugly. I would rather avoid it.
Do I understand correctly that we don't have a way represent pluggable,
but not present memory in EFI memory map?
IIUC, EFI_MEMORY_HOT_PLUGGABLE is actually present, but unpluggable
memory.
Maybe it would be better just allocate bitmap upto maxmem?
And fix EFI spec to add pluggable-but-not-present attribute.
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-06-24 12:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-23 10:17 [RFCv2 PATCH 0/6] Support memory hotplug/unplug for TDX CoCo guests Zhenzhong Duan
2026-06-23 10:17 ` [RFCv2 PATCH 1/6] efi/unaccepted: Support hotplug memory in unaccepted bitmap via SRAT Zhenzhong Duan
2026-06-24 12:25 ` Kiryl Shutsemau [this message]
2026-06-24 14:23 ` Pratik R. Sampat
2026-06-23 10:17 ` [RFCv2 PATCH 2/6] efi/unaccepted: Set unaccepted bits for all hotplug memory Zhenzhong Duan
2026-06-24 12:29 ` Kiryl Shutsemau
2026-06-23 10:17 ` [RFCv2 PATCH 3/6] efi/unaccepted: Create plugged bitmap to support hotplug memory in coco guest Zhenzhong Duan
2026-06-23 10:17 ` [RFCv2 PATCH 4/6] x86/tdx: Implement arch_unaccept_memory() Zhenzhong Duan
2026-06-23 10:17 ` [RFCv2 PATCH 5/6] mm/memory_hotplug: Support ACPI hotplug/unplug for coco guest Zhenzhong Duan
2026-06-24 12:33 ` Kiryl Shutsemau
2026-06-23 10:17 ` [RFCv2 PATCH 6/6] virtio-mem: Support memory " Zhenzhong Duan
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