target/arm: Add cpu properties to control pauth

The crypto overhead of emulating pauth can be significant for
some workloads.  Add two boolean properties that allows the
feature to be turned off, on with the architected algorithm,
or on with an implementation defined algorithm.

We need two intermediate booleans to control the state while
parsing properties lest we clobber ID_AA64ISAR1 into an invalid
intermediate state.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210111235740.462469-3-richard.henderson@linaro.org
[PMM: fixed docs typo, tweaked text to clarify that the impdef
algorithm is specific to QEMU]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 84784070a7..f58aada410 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -197,9 +197,11 @@ typedef struct {
 #ifdef TARGET_AARCH64
 # define ARM_MAX_VQ    16
 void arm_cpu_sve_finalize(ARMCPU *cpu, Error **errp);
+void arm_cpu_pauth_finalize(ARMCPU *cpu, Error **errp);
 #else
 # define ARM_MAX_VQ    1
 static inline void arm_cpu_sve_finalize(ARMCPU *cpu, Error **errp) { }
+static inline void arm_cpu_pauth_finalize(ARMCPU *cpu, Error **errp) { }
 #endif
 
 typedef struct ARMVectorReg {
@@ -947,6 +949,14 @@ struct ARMCPU {
     uint64_t reset_cbar;
     uint32_t reset_auxcr;
     bool reset_hivecs;
+
+    /*
+     * Intermediate values used during property parsing.
+     * Once finalized, the values should be read from ID_AA64ISAR1.
+     */
+    bool prop_pauth;
+    bool prop_pauth_impdef;
+
     /* DCZ blocksize, in log_2(words), ie low 4 bits of DCZID_EL0 */
     uint32_t dcz_blocksize;
     uint64_t rvbar;