[PATCH v2 06/14] arm64: Override set_fixmap_io

Steven Price
2024-04-12T08:42:36Z

From: Suzuki K Poulose <suzuki.poulose@arm.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@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/arm64/include/asm/fixmap.h | 4 +++-
arch/arm64/mm/mmu.c | 13 +++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 87e307804b99..f765943b088c 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -107,7 +107,9 @@ void __init early_fixmap_init(void);
#define __late_set_fixmap __set_fixmap
#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)

-extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
+#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 495b732d5af3..79d84db9ffcb 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1179,6 +1179,19 @@ void vmemmap_free(unsigned long start, unsigned long end,
}
#endif /* CONFIG_MEMORY_HOTPLUG */

+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);
+}
+
int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
{
pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
--
2.34.1