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Sampat" To: , , , , CC: , , , , , , , , , , , Subject: [RFC PATCH 1/4] efi/libstub: Decouple memory bitmap from the unaccepted table Date: Tue, 25 Nov 2025 11:57:50 -0600 Message-ID: <20251125175753.1428857-2-prsampat@amd.com> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251125175753.1428857-1-prsampat@amd.com> References: <20251125175753.1428857-1-prsampat@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SN1PEPF000252A2:EE_|SN7PR12MB7854:EE_ X-MS-Office365-Filtering-Correlation-Id: 0d64bdaa-f58d-487c-29aa-08de2c4c32f5 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|1800799024|376014|7416014|36860700013; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?FzQRAK6+eEUF4t2XsSgiduOM5KYNEnPjxWaoWd0xtWdCX6TDRg31BrYbx4zy?= =?us-ascii?Q?S0EIc09MLCOBqLV8dj6tVA2GGVchDQOSoQp/sNoEeMp9CNvp20UghiU81ylr?= =?us-ascii?Q?oEWY+sqlYSIk4FU/0jlKN/PvqGkLDrKwa6K0oFV07oO21LOk7/DrjPUrxzNv?= =?us-ascii?Q?ClIVuR0v2DcdfO2EmZZE5dbkE6nKVxf3FPJ1+sdpSz2za1oZNmby+ka+OW2D?= =?us-ascii?Q?WjPk4l1VJRXy/8YTGg92PZI292nf9fBDu41iVjELq+Vh1UumQDfaodb1V70f?= =?us-ascii?Q?6+tYceijVAPjettsE88ly3iywDjGTe7AWUQZpYzCxb7f3IkNgyFuKfkGOMoA?= =?us-ascii?Q?9YdazU3OyDv82kC2d7efHSSgRn4QXlyryVzaGM7NG6BagYuxBiir1hEXXixs?= =?us-ascii?Q?Af+CVYAFF9gylCQoOwjqQl2vgC3QCbS4S2xEKwW8pzbx2lGoJVBSP4nZi4sP?= =?us-ascii?Q?dQYWFQJXwBWaARsSu9jemDszn3ldemo4EdMtvfRpttXOZ6Md/n5te96zOh58?= =?us-ascii?Q?g6Sxo2RjbYgncNPO0PJKV7EoTiIrVqIprtFGO7SKKvcIT3lri8icquYD9GM7?= =?us-ascii?Q?dpnkWzwaGqSlnPOyNNxz9/0S0xIBj7rvPHvUEGtABjFU+/nTHj4PeacyS89R?= =?us-ascii?Q?VfUGuxsmgzJs/eddQYCWQzsWdcRarawwZGcPO21xjq7Bsxt+w2OhUbVFdgGR?= =?us-ascii?Q?Xj+ixP7Tu9abLUB6aPvXe0OQTEPtSk/ZM8KLaMU45VdXnddjtwQoXG2Rg1EE?= =?us-ascii?Q?KwkzREbPbB/QLt9kiLXZH3hZf8/w2BsPKvnJwXw+D1IHgCASv0koVdK9NKQq?= =?us-ascii?Q?cMOGaTEpB7fTtZClKkpIda9ULO6Kj1EmaAUeG5siEjOnU0rdaE4QGB04KzWT?= =?us-ascii?Q?O/PqGyHQzoN4p6NfmSY7e66amKSBXoIkFQmbikgEmFDnau1SKPr9YJIntoSu?= =?us-ascii?Q?Z4tItM71+/Bf3qlqloLHCAq1YeJiGsDxrYbaqarN501NYSyd6yt9HCfGL93V?= =?us-ascii?Q?k1cKeVQdRQADWv+Lbp2z1lj5b+pkUS57xD02USuQJB1t4PkJQ3w349bsiILo?= =?us-ascii?Q?bj4WUXhYuqzh15kN3JzhpHN6nFx2h8JNcxYuhdlYKy4hEQfDzONrkGs2Jfte?= =?us-ascii?Q?o6uzcN6BlExeUAE0VYFzuzBi5CssYTVXXCEyOPkJ7Dm0t7HONnFxh+8co1mn?= =?us-ascii?Q?WA37bPKqEHrL5wUkggT+hE46FWaNVuIToiI1OpXobTiiJJyuUxA/STC0ik0f?= =?us-ascii?Q?1Je8OtDx7u+wlX/qP6ybMBWAOja/E/PWtL9pL/7/+EkAlAFv/tIAnrsz7tvH?= =?us-ascii?Q?gIrpM3xW9TO0kG+x8sftXOK3YuDHHFpNthVT0hCxVJphnE3NoqqXbeLxM0UP?= =?us-ascii?Q?BtNFHoMkMI9WOAoKdTt7Bg3Pu4O0HaR9vq/X6y/69bOk59fiOwE3KNhPOLP0?= =?us-ascii?Q?ypOZNnTBfzoEfWn5snvRUZe2VNhTT+kE6hhnUXhdsesHohd8UkeLpdJt5Zev?= =?us-ascii?Q?cZ1Ai02C9sgD1CvC2XIZjCyozRx1oCgisTOJra9oKq9oPYUhCCaK/y+gBiXC?= =?us-ascii?Q?iwUAA8GF50nZomTNvdw=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(1800799024)(376014)(7416014)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Nov 2025 17:58:11.6590 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 0d64bdaa-f58d-487c-29aa-08de2c4c32f5 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SN1PEPF000252A2.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB7854 Content-Type: text/plain; charset="utf-8" Memory hotplug in secure environments requires the unaccepted memory bitmap to grow as new memory is added. Currently, the bitmap is implemented as a flexible array member at the end of struct efi_unaccepted_memory, which is reserved by memblock at boot and cannot be resized without reallocating the entire structure. Replace the flexible array member with a pointer. This allows the bitmap to be allocated and managed independently from the unaccepted memory table, enabling dynamic growth to support memory hotplug. Signed-off-by: Pratik R. Sampat --- arch/x86/boot/compressed/efi.h | 2 +- arch/x86/include/asm/unaccepted_memory.h | 9 +++++++++ .../firmware/efi/libstub/unaccepted_memory.c | 11 ++++++++++- drivers/firmware/efi/unaccepted_memory.c | 19 ++++++++++++++----- include/linux/efi.h | 2 +- 5 files changed, 35 insertions(+), 8 deletions(-) diff --git a/arch/x86/boot/compressed/efi.h b/arch/x86/boot/compressed/efi.h index b22300970f97..4f7027f33def 100644 --- a/arch/x86/boot/compressed/efi.h +++ b/arch/x86/boot/compressed/efi.h @@ -102,7 +102,7 @@ struct efi_unaccepted_memory { u32 unit_size; u64 phys_base; u64 size; - unsigned long bitmap[]; + unsigned long *bitmap; }; =20 static inline int efi_guidcmp (efi_guid_t left, efi_guid_t right) diff --git a/arch/x86/include/asm/unaccepted_memory.h b/arch/x86/include/as= m/unaccepted_memory.h index f5937e9866ac..5da80e68d718 100644 --- a/arch/x86/include/asm/unaccepted_memory.h +++ b/arch/x86/include/asm/unaccepted_memory.h @@ -24,4 +24,13 @@ static inline struct efi_unaccepted_memory *efi_get_unac= cepted_table(void) return NULL; return __va(efi.unaccepted); } + +static inline unsigned long *efi_get_unaccepted_bitmap(void) +{ + struct efi_unaccepted_memory *unaccepted =3D efi_get_unaccepted_table(); + + if (!unaccepted) + return NULL; + return __va(unaccepted->bitmap); +} #endif diff --git a/drivers/firmware/efi/libstub/unaccepted_memory.c b/drivers/fir= mware/efi/libstub/unaccepted_memory.c index 757dbe734a47..c1370fc14555 100644 --- a/drivers/firmware/efi/libstub/unaccepted_memory.c +++ b/drivers/firmware/efi/libstub/unaccepted_memory.c @@ -63,13 +63,22 @@ efi_status_t allocate_unaccepted_bitmap(__u32 nr_desc, EFI_UNACCEPTED_UNIT_SIZE * BITS_PER_BYTE); =20 status =3D efi_bs_call(allocate_pool, EFI_ACPI_RECLAIM_MEMORY, - sizeof(*unaccepted_table) + bitmap_size, + sizeof(*unaccepted_table), (void **)&unaccepted_table); if (status !=3D EFI_SUCCESS) { efi_err("Failed to allocate unaccepted memory config table\n"); return status; } =20 + status =3D efi_bs_call(allocate_pool, EFI_ACPI_RECLAIM_MEMORY, + bitmap_size, + (void **)&unaccepted_table->bitmap); + if (status !=3D EFI_SUCCESS) { + efi_bs_call(free_pool, unaccepted_table); + efi_err("Failed to allocate unaccepted memory bitmap\n"); + return status; + } + unaccepted_table->version =3D 1; unaccepted_table->unit_size =3D EFI_UNACCEPTED_UNIT_SIZE; unaccepted_table->phys_base =3D unaccepted_start; diff --git a/drivers/firmware/efi/unaccepted_memory.c b/drivers/firmware/ef= i/unaccepted_memory.c index c2c067eff634..4479aad258f8 100644 --- a/drivers/firmware/efi/unaccepted_memory.c +++ b/drivers/firmware/efi/unaccepted_memory.c @@ -36,7 +36,7 @@ void accept_memory(phys_addr_t start, unsigned long size) unsigned long range_start, range_end; struct accept_range range, *entry; phys_addr_t end =3D start + size; - unsigned long flags; + unsigned long flags, *bitmap; u64 unit_size; =20 unaccepted =3D efi_get_unaccepted_table(); @@ -124,8 +124,12 @@ void accept_memory(phys_addr_t start, unsigned long si= ze) list_add(&range.list, &accepting_list); =20 range_start =3D range.start; - for_each_set_bitrange_from(range_start, range_end, unaccepted->bitmap, - range.end) { + + bitmap =3D efi_get_unaccepted_bitmap(); + if (!bitmap) + return; + + for_each_set_bitrange_from(range_start, range_end, bitmap, range.end) { unsigned long phys_start, phys_end; unsigned long len =3D range_end - range_start; =20 @@ -147,7 +151,7 @@ void accept_memory(phys_addr_t start, unsigned long siz= e) arch_accept_memory(phys_start, phys_end); =20 spin_lock(&unaccepted_memory_lock); - bitmap_clear(unaccepted->bitmap, range_start, len); + bitmap_clear(bitmap, range_start, len); } =20 list_del(&range.list); @@ -197,7 +201,12 @@ bool range_contains_unaccepted_memory(phys_addr_t star= t, unsigned long size) =20 spin_lock_irqsave(&unaccepted_memory_lock, flags); while (start < end) { - if (test_bit(start / unit_size, unaccepted->bitmap)) { + unsigned long *bitmap =3D efi_get_unaccepted_bitmap(); + + if (!bitmap) + break; + + if (test_bit(start / unit_size, bitmap)) { ret =3D true; break; } diff --git a/include/linux/efi.h b/include/linux/efi.h index a98cc39e7aaa..a74b393c54d8 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -545,7 +545,7 @@ struct efi_unaccepted_memory { u32 unit_size; u64 phys_base; u64 size; - unsigned long bitmap[]; + unsigned long *bitmap; }; =20 /* --=20 2.51.1