[PATCH v3 07/14] arm64: Make the PHYS_MASK_SHIFT dynamic

[Steven Price]

Make the PHYS_MASK_SHIFT dynamic for Realms. This is only is required
for masking the PFN from a pte entry. For a realm phys_mask_shift is
reduced if the RMM reports a smaller configured size for the guest.

Co-developed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>

---
v3: Drop the MAX_PHYS_MASK{,_SHIFT} definitions as they are no longer
needed.
---
 arch/arm64/include/asm/pgtable-hwdef.h | 6 ------
 arch/arm64/include/asm/pgtable.h       | 5 +++++
 arch/arm64/kernel/rsi.c                | 5 +++++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index 9943ff0af4c9..2e3af0693bd8 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -203,12 +203,6 @@
  */
 #define PTE_S2_MEMATTR(t)	(_AT(pteval_t, (t)) << 2)
 
-/*
- * Highest possible physical address supported.
- */
-#define PHYS_MASK_SHIFT		(CONFIG_ARM64_PA_BITS)
-#define PHYS_MASK		((UL(1) << PHYS_MASK_SHIFT) - 1)
-
 #define TTBR_CNP_BIT		(UL(1) << 0)
 
 /*
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index f8efbc128446..11d614d83317 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -39,6 +39,11 @@
 #include <linux/sched.h>
 #include <linux/page_table_check.h>
 
+extern unsigned int phys_mask_shift;
+
+#define PHYS_MASK_SHIFT		(phys_mask_shift)
+#define PHYS_MASK		((1UL << PHYS_MASK_SHIFT) - 1)
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 #define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
 
diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index d34e05b339ae..c5c03e8e341a 100644
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c
@@ -12,6 +12,8 @@ struct realm_config config;
 unsigned long prot_ns_shared;
 EXPORT_SYMBOL(prot_ns_shared);
 
+unsigned int phys_mask_shift = CONFIG_ARM64_PA_BITS;
+
 DEFINE_STATIC_KEY_FALSE_RO(rsi_present);
 EXPORT_SYMBOL(rsi_present);
 
@@ -72,6 +74,9 @@ void __init arm64_rsi_init(void)
 		return;
 	prot_ns_shared = BIT(config.ipa_bits - 1);
 
+	if (config.ipa_bits - 1 < phys_mask_shift)
+		phys_mask_shift = config.ipa_bits - 1;
+
 	static_branch_enable(&rsi_present);
 }
 
-- 
2.34.1