[PATCH] arm64: rsi: use linear-map alias for realm config buffer

[PATCH] arm64: rsi: use linear-map alias for realm config buffer

[Aneesh Kumar K.V (Arm)]

rsi_get_realm_config() passes its argument to virt_to_phys(), but
&config is a kernel image address and not a linear-map alias.
On arm64 this triggers the below warning:

 virt_to_phys used for non-linear address: (____ptrval____) (config+0x0/0x1000)
 WARNING: arch/arm64/mm/physaddr.c:15 at __virt_to_phys+0x50/0x70, CPU#0: swapper/0
 Modules linked in:
 .....
 Hardware name: linux,dummy-virt (DT)
 pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __virt_to_phys+0x50/0x70
 lr : __virt_to_phys+0x4c/0x70
 .....
 ......
 Call trace:
  __virt_to_phys+0x50/0x70 (P)
  arm64_rsi_init+0xa0/0x1b8
  setup_arch+0x13c/0x1a0
  start_kernel+0x68/0x398
  __primary_switched+0x88/0x90

Pass lm_alias(&config) instead so the RSI call uses the linear-map
alias of the same buffer and avoids the boot-time warning.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Gavin Shan <gshan@redhat.com>
---
 arch/arm64/kernel/rsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index 9e846ce4ef9c..92160f2e57ff 100644
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c
@@ -145,7 +145,7 @@ void __init arm64_rsi_init(void)
 		return;
 	if (!rsi_version_matches())
 		return;
-	if (WARN_ON(rsi_get_realm_config(&config)))
+	if (WARN_ON(rsi_get_realm_config(lm_alias(&config))))
 		return;
 	prot_ns_shared = __phys_to_pte_val(BIT(config.ipa_bits - 1));
 
-- 
2.43.0

Re: [PATCH] arm64: rsi: use linear-map alias for realm config buffer

[Catalin Marinas]

On Tue, 07 Apr 2026 20:59:00 +0530, Aneesh Kumar K.V (Arm) wrote:
> rsi_get_realm_config() passes its argument to virt_to_phys(), but
> &config is a kernel image address and not a linear-map alias.
> On arm64 this triggers the below warning:
> 
>  virt_to_phys used for non-linear address: (____ptrval____) (config+0x0/0x1000)
>  WARNING: arch/arm64/mm/physaddr.c:15 at __virt_to_phys+0x50/0x70, CPU#0: swapper/0
>  Modules linked in:
>  .....
>  Hardware name: linux,dummy-virt (DT)
>  pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>  pc : __virt_to_phys+0x50/0x70
>  lr : __virt_to_phys+0x4c/0x70
>  .....
>  ......
>  Call trace:
>   __virt_to_phys+0x50/0x70 (P)
>   arm64_rsi_init+0xa0/0x1b8
>   setup_arch+0x13c/0x1a0
>   start_kernel+0x68/0x398
>   __primary_switched+0x88/0x90
> 
> [...]

Applied to arm64 (for-next/misc), thanks!

[1/1] arm64: rsi: use linear-map alias for realm config buffer
      https://git.kernel.org/arm64/c/34e563947c76

I did not add a Fixes tag, it's just a debug warning, otherwise it
functions correctly.

-- 
Catalin