linux-kernel - [PATCH AUTOSEL 5.10 2/6] efi: Don't add memblocks for soft-reserved memory

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Message-ID: <20240213002409.673084-2-sashal@kernel.org>
Date: Mon, 12 Feb 2024 19:24:04 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Andrew Bresticker <abrestic@...osinc.com>,
	Ard Biesheuvel <ardb@...nel.org>,
	Sasha Levin <sashal@...nel.org>,
	linux-efi@...r.kernel.org
Subject: [PATCH AUTOSEL 5.10 2/6] efi: Don't add memblocks for soft-reserved memory

From: Andrew Bresticker <abrestic@...osinc.com>

[ Upstream commit 0bcff59ef7a652fcdc6d535554b63278c2406c8f ]

Adding memblocks for soft-reserved regions prevents them from later being
hotplugged in by dax_kmem.

Signed-off-by: Andrew Bresticker <abrestic@...osinc.com>
Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/firmware/efi/efi-init.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/firmware/efi/efi-init.c b/drivers/firmware/efi/efi-init.c
index f55a92ff12c0..86da3c7a5036 100644
--- a/drivers/firmware/efi/efi-init.c
+++ b/drivers/firmware/efi/efi-init.c
@@ -141,15 +141,6 @@ static __init int is_usable_memory(efi_memory_desc_t *md)
 	case EFI_BOOT_SERVICES_DATA:
 	case EFI_CONVENTIONAL_MEMORY:
 	case EFI_PERSISTENT_MEMORY:
-		/*
-		 * Special purpose memory is 'soft reserved', which means it
-		 * is set aside initially, but can be hotplugged back in or
-		 * be assigned to the dax driver after boot.
-		 */
-		if (efi_soft_reserve_enabled() &&
-		    (md->attribute & EFI_MEMORY_SP))
-			return false;
-
 		/*
 		 * According to the spec, these regions are no longer reserved
 		 * after calling ExitBootServices(). However, we can only use
@@ -194,6 +185,16 @@ static __init void reserve_regions(void)
 		size = npages << PAGE_SHIFT;
 
 		if (is_memory(md)) {
+			/*
+			 * Special purpose memory is 'soft reserved', which
+			 * means it is set aside initially. Don't add a memblock
+			 * for it now so that it can be hotplugged back in or
+			 * be assigned to the dax driver after boot.
+			 */
+			if (efi_soft_reserve_enabled() &&
+			    (md->attribute & EFI_MEMORY_SP))
+				continue;
+
 			early_init_dt_add_memory_arch(paddr, size);
 
 			if (!is_usable_memory(md))
-- 
2.43.0