On 19/08/2024 15:11, Suzuki K Poulose wrote:

Hi Steven

On 19/08/2024 14:19, Steven Price wrote:

quoted

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

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@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
New patch for v5
---
  arch/arm64/kernel/rsi.c | 15 +++++++++++++++
  arch/arm64/mm/mmu.c     |  2 +-
  2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index 381a5b9a5333..672dd6862298 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;

@@ -93,6 +95,16 @@ bool arm64_rsi_is_protected_mmio(phys_addr_t base,

size_t size)
  }
  EXPORT_SYMBOL(arm64_rsi_is_protected_mmio);
  +static int realm_ioremap_hook(phys_addr_t phys, size_t size,
pgprot_t *prot)
+{
+    if (arm64_rsi_is_protected_mmio(phys, size))
+        *prot = pgprot_encrypted(*prot);
+    else
+        *prot = pgprot_decrypted(*prot);
+
+    return 0;
+}
+
  void __init arm64_rsi_init(void)
  {
      /*

@@ -107,6 +119,9 @@ 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;
+
      static_branch_enable(&rsi_present);
  }
  diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 06b66c23c124..0c2fa35beca0 100644

--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c

@@ -1207,7 +1207,7 @@ void set_fixmap_io(enum fixed_addresses idx,

phys_addr_t phys)
      else
          prot = pgprot_encrypted(prot);
  -    __set_fixmap(idx, phys, prot);
+    __set_fixmap(idx, phys & PAGE_MASK, prot);

This looks like it should be part of the previous patch ? Otherwise
looks good to me.

Good spot - yes it should!

Thanks,
Steve