linux-kernel - [RFC PATCH 3/3] iommu/vt-d: Show region type in arch_rmrr_sanity

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Message-Id: <20220611204859.234975-3-atomlin@redhat.com>
Date:   Sat, 11 Jun 2022 21:48:59 +0100
From:   Aaron Tomlin <atomlin@...hat.com>
To:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, joro@...tes.org, will@...nel.org,
        dwmw2@...radead.org, baolu.lu@...ux.intel.com, hpa@...or.com
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        atomlin@...mlin.com
Subject: [RFC PATCH 3/3] iommu/vt-d: Show region type in arch_rmrr_sanity_check()

This patch will attempt to describe the region type in the event
that a given RMRR entry is not within a reserved region.

Signed-off-by: Aaron Tomlin <atomlin@...hat.com>
---
 arch/x86/include/asm/iommu.h | 9 ++++++---
 arch/x86/kernel/e820.c       | 5 +++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index bf1ed2ddc74b..d21366644520 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -17,12 +17,15 @@ arch_rmrr_sanity_check(struct acpi_dmar_reserved_memory *rmrr)
 {
 	u64 start = rmrr->base_address;
 	u64 end = rmrr->end_address + 1;
+	struct e820_entry *entry;
 
-	if (e820__mapped_all(start, end, E820_TYPE_RESERVED))
+	entry = __e820__mapped_all(start, end, 0);
+
+	if (entry && entry->type == E820_TYPE_RESERVED)
 		return 0;
 
-	pr_err(FW_BUG "No firmware reserved region can cover this RMRR [%#018Lx-%#018Lx], contact BIOS vendor for fixes\n",
-	       start, end - 1);
+	pr_err(FW_BUG "No firmware reserved region can cover this RMRR [%s: %#018Lx-%#018Lx], contact BIOS vendor for fixes\n",
+	       e820_type_to_string(entry), start, end - 1);
 	return -EINVAL;
 }
 
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 95b994cf80cd..165e9a444bb9 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1073,7 +1073,7 @@ void __init e820__finish_early_params(void)
 
 const char *__init e820_type_to_string(struct e820_entry *entry)
 {
-	switch (entry->type) {
+	switch (entry && entry->type) {
 	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */
 	case E820_TYPE_RAM:		return "System RAM";
 	case E820_TYPE_ACPI:		return "ACPI Tables";
@@ -1083,8 +1083,9 @@ const char *__init e820_type_to_string(struct e820_entry *entry)
 	case E820_TYPE_PMEM:		return "Persistent Memory";
 	case E820_TYPE_RESERVED:	return "Reserved";
 	case E820_TYPE_SOFT_RESERVED:	return "Soft Reserved";
-	default:			return "Unknown E820 type";
+	default:			break;
 	}
+	return "Unknown E820 type";
 }
 
 static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)
-- 
2.34.1