linux-kernel - [RFC PATCH 07/14] arm64: Override set_fixmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230127112758.37891-8-steven.price@arm.com>
Date:   Fri, 27 Jan 2023 11:27:51 +0000
From:   Steven Price <steven.price@....com>
To:     kvmarm@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org
Cc:     Steven Price <steven.price@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        James Morse <james.morse@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Zenghui Yu <yuzenghui@...wei.com>,
        linux-kernel@...r.kernel.org, Joey Gouly <joey.gouly@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Christoffer Dall <christoffer.dall@....com>,
        Fuad Tabba <tabba@...gle.com>, linux-coco@...ts.linux.dev
Subject: [RFC PATCH 07/14] arm64: Override set_fixmap_io

From: Suzuki K Poulose <suzuki.poulose@....com>

Override the set_fixmap_io to set shared permission for the host
in case of a CC guest. For now we mark it shared unconditionally.
Future changes could filter the physical address and make the
decision accordingly.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Steven Price <steven.price@....com>
---
 arch/arm64/include/asm/fixmap.h |  2 ++
 arch/arm64/mm/mmu.c             | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 09ba9fe3b02c..1acafc1c7fae 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -107,6 +107,8 @@ void __init early_fixmap_init(void);
 #define __late_set_fixmap __set_fixmap
 #define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
 
+#define set_fixmap_io set_fixmap_io
+void set_fixmap_io(enum fixed_addresses idx, phys_addr_t phys);
 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
 
 #include <asm-generic/fixmap.h>
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 14c87e8d69d8..33fda73c669b 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1279,6 +1279,19 @@ void __set_fixmap(enum fixed_addresses idx,
 	}
 }
 
+void set_fixmap_io(enum fixed_addresses idx, phys_addr_t phys)
+{
+	pgprot_t prot = FIXMAP_PAGE_IO;
+
+	/*
+	 * For now we consider all I/O as non-secure. For future
+	 * filter the I/O base for setting appropriate permissions.
+	 */
+	prot = __pgprot(pgprot_val(prot) | PROT_NS_SHARED);
+
+	return __set_fixmap(idx, phys, prot);
+}
+
 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 {
 	const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
-- 
2.34.1