diff mbox series

[v5,03/28] arm64/fpsimd: Check enable bit for FA64 when saving EFI state

Message ID 20250417-kvm-arm64-sme-v5-3-f469a2d5f574@kernel.org (mailing list archive)
State New
Headers show
Series KVM: arm64: Implement support for SME | expand

Commit Message

Mark Brown April 17, 2025, 12:25 a.m. UTC 
Currently when deciding if we need to save FFR when in streaming mode prior
to EFI calls we check if FA64 is supported by the system. Since KVM guest
support will mean that FA64 might be enabled and disabled at runtime switch
to checking if traps for FA64 are enabled in SMCR_EL1 instead.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/kernel/fpsimd.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 266ce7a9f195..83a4f8d3e895 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1913,6 +1913,11 @@  static DEFINE_PER_CPU(bool, efi_sm_state);
  * either doing something wrong or you need to propose some refactoring.
  */
 
+static bool fa64_enabled(void)
+{
+	return read_sysreg_s(SYS_SMCR_EL1) & SMCR_ELx_FA64;
+}
+
 /*
  * __efi_fpsimd_begin(): prepare FPSIMD for making an EFI runtime services call
  */
@@ -1947,7 +1952,7 @@  void __efi_fpsimd_begin(void)
 				 * Unless we have FA64 FFR does not
 				 * exist in streaming mode.
 				 */
-				if (!system_supports_fa64())
+				if (!fa64_enabled())
 					ffr = !(svcr & SVCR_SM_MASK);
 			}
 
@@ -1998,7 +2003,7 @@  void __efi_fpsimd_end(void)
 					 * Unless we have FA64 FFR does not
 					 * exist in streaming mode.
 					 */
-					if (!system_supports_fa64())
+					if (!fa64_enabled())
 						ffr = false;
 				}
 			}