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

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Message-Id: <20180918024837.17710-3-lijiang@redhat.com>
Date:   Tue, 18 Sep 2018 10:48:37 +0800
From:   Lianbo Jiang <lijiang@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, akpm@...ux-foundation.org, dyoung@...hat.com
Subject: [PATCH 2/2] x86/kexec_file: add reserved e820 ranges to 2nd kernel e820 table

e820 reserved ranges is useful in kdump kernel, we have added this 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 unencrypted.
For normal boot these ranges sit in e820 reserved ranges thus the early
ioremap code naturally map them as unencrypted. So if we have same e820
reserve setup in kdump kernel then it will just work like normal kernel.

Signed-off-by: Dave Young <dyoung@...hat.com>
Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
---
 arch/x86/kernel/crash.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 3c113e6545a3..db453e9c117b 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -384,6 +384,12 @@ 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);
 
+	/* Add all reserved ranges */
+	cmd.type = E820_TYPE_RESERVED;
+	flags = IORESOURCE_MEM;
+	walk_iomem_res_desc(IORES_DESC_NONE, flags, 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