linux-kernel - [PATCH 2/2 v4] x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table

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Date:   Mon, 22 Oct 2018 15:47:07 +0800
From:   Lianbo Jiang <lijiang@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     kexec@...ts.infradead.org, x86@...nel.org, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, thomas.lendacky@....com,
        dyoung@...hat.com, bhe@...hat.com
Subject: [PATCH 2/2 v4] x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table

E820 reserved ranges is useful in kdump kernel, it has been added in
kexec-tools code.

One reason is PCI mmconf (extended mode) requires reserved region otherwise
it falls back to legacy mode.

When AMD SME kdump support, it needs to map dmi table area as decrypted.
For normal boot, these ranges sit in e820 reserved ranges, thus the early
ioremap code naturally map them as decrypted. If it also has same e820
reserve setup in kdump kernel then it will just work like normal kernel.

Suggested-by: Dave Young <dyoung@...hat.com>
Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
---
 arch/x86/kernel/crash.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index ae724a6e0a5f..d3167125800e 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -384,6 +384,10 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 	walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
 			memmap_entry_callback);
 
+	cmd.type = E820_TYPE_RESERVED;
+	walk_iomem_res_desc(IORES_DESC_NONE, 0, 0, -1, &cmd,
+			   memmap_entry_callback);
+
 	/* Add crashk_low_res region */
 	if (crashk_low_res.end) {
 		ei.addr = crashk_low_res.start;
-- 
2.17.1