arm64: realm: Query IPA size from the RMM

The top bit of the configured IPA size is used as an attribute to
control whether the address is protected or shared. Query the
configuration from the RMM to assertain which bit this is.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20241017131434.40935-4-steven.price@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 2a11d0c..820a3b0 100644 (file)
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -68,8 +68,12 @@
 
 #include <asm/cpufeature.h>
 #include <asm/pgtable-types.h>
+#include <asm/rsi.h>
 
 extern bool arm64_use_ng_mappings;
+extern unsigned long prot_ns_shared;
+
+#define PROT_NS_SHARED         (is_realm_world() ? prot_ns_shared : 0)
 
 #define PTE_MAYBE_NG           (arm64_use_ng_mappings ? PTE_NG : 0)
 #define PMD_MAYBE_NG           (arm64_use_ng_mappings ? PMD_SECT_NG : 0)

diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index c575831..cea8f0d 100644 (file)
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c
@@ -8,6 +8,11 @@
 #include <linux/psci.h>
 #include <asm/rsi.h>
 
+static struct realm_config config;
+
+unsigned long prot_ns_shared;
+EXPORT_SYMBOL(prot_ns_shared);
+
 DEFINE_STATIC_KEY_FALSE_RO(rsi_present);
 EXPORT_SYMBOL(rsi_present);
 
@@ -68,6 +73,9 @@ void __init arm64_rsi_init(void)
                return;
        if (!rsi_version_matches())
                return;
+       if (WARN_ON(rsi_get_realm_config(&config)))
+               return;
+       prot_ns_shared = BIT(config.ipa_bits - 1);
 
        arm64_rsi_setup_memory();