[PATCH v6 05/11] arm64: rsi: Map unprotected MMIO as decrypted

[Steven Price]

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

Instead of marking every MMIO as shared, check if the given region is
"Protected" and apply the permissions accordingly.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
New patch for v5
---
 arch/arm64/kernel/rsi.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index d7bba4cee627..f1add76f89ce 100644
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c
@@ -6,6 +6,8 @@
 #include <linux/jump_label.h>
 #include <linux/memblock.h>
 #include <linux/psci.h>
+
+#include <asm/io.h>
 #include <asm/rsi.h>
 
 struct realm_config config;
@@ -92,6 +94,16 @@ bool arm64_is_protected_mmio(phys_addr_t base, size_t size)
 }
 EXPORT_SYMBOL(arm64_is_protected_mmio);
 
+static int realm_ioremap_hook(phys_addr_t phys, size_t size, pgprot_t *prot)
+{
+	if (arm64_is_protected_mmio(phys, size))
+		*prot = pgprot_encrypted(*prot);
+	else
+		*prot = pgprot_decrypted(*prot);
+
+	return 0;
+}
+
 void __init arm64_rsi_init(void)
 {
 	if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_SMC)
@@ -102,6 +114,9 @@ void __init arm64_rsi_init(void)
 		return;
 	prot_ns_shared = BIT(config.ipa_bits - 1);
 
+	if (arm64_ioremap_prot_hook_register(realm_ioremap_hook))
+		return;
+
 	arm64_rsi_setup_memory();
 
 	static_branch_enable(&rsi_present);
-- 
2.34.1