linux-kernel - [PATCH 4/5 V5] Adjust some permanent mappings in unencrypted ways for kdump when SME is enabled.

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Date:   Mon,  2 Jul 2018 15:26:38 +0800
From:   Lianbo Jiang <lijiang@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     mingo@...hat.com, tglx@...utronix.de, hpa@...or.com,
        ebiederm@...ssion.com, joro@...tes.org, thomas.lendacky@....com,
        dyoung@...hat.com, kexec@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, bhe@...hat.com
Subject: [PATCH 4/5 V5] Adjust some permanent mappings in unencrypted ways for kdump when SME is enabled.

For kdump, the acpi table and dmi table will need to be remapped in
unencrypted ways during early init, they have just a simple wrapper
around early_memremap(), but the early_memremap() remaps the memory
in encrypted ways by default when SME is enabled, so we put some logic
into the early_memremap_pgprot_adjust(), which will have an opportunity
to adjust it.

Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
---
 arch/x86/mm/ioremap.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index e01e6c6..3c1c8c4 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -689,8 +689,17 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr,
 	encrypted_prot = true;
 
 	if (sme_active()) {
+		/*
+		 * In kdump mode, the acpi table and dmi table will need to
+		 * be remapped in unencrypted ways during early init when
+		 * SME is enabled. They have just a simple wrapper around
+		 * early_memremap(), but the early_memremap() remaps the
+		 * memory in encrypted ways by default when SME is enabled,
+		 * so we must adjust it.
+		 */
 		if (early_memremap_is_setup_data(phys_addr, size) ||
-		    memremap_is_efi_data(phys_addr, size))
+		    memremap_is_efi_data(phys_addr, size) ||
+		    is_kdump_kernel())
 			encrypted_prot = false;
 	}
 
-- 
2.9.5