target/arm: Add ID_AA64SMFR0_EL1

This register is allocated from the existing block of id registers,
so it is already RES0 for cpus that do not implement SME.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220607203306.657998-21-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 34 insertions, 6 deletions

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 2e6153c..78dbcb5 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -966,6 +966,7 @@ struct ArchCPU {
         uint64_t id_aa64dfr0;
         uint64_t id_aa64dfr1;
         uint64_t id_aa64zfr0;
+        uint64_t id_aa64smfr0;
         uint64_t reset_pmcr_el0;
     } isar;
     uint64_t midr;
@@ -2190,6 +2191,15 @@ FIELD(ID_AA64ZFR0, I8MM, 44, 4)
 FIELD(ID_AA64ZFR0, F32MM, 52, 4)
 FIELD(ID_AA64ZFR0, F64MM, 56, 4)
 
+FIELD(ID_AA64SMFR0, F32F32, 32, 1)
+FIELD(ID_AA64SMFR0, B16F32, 34, 1)
+FIELD(ID_AA64SMFR0, F16F32, 35, 1)
+FIELD(ID_AA64SMFR0, I8I32, 36, 4)
+FIELD(ID_AA64SMFR0, F64F64, 48, 1)
+FIELD(ID_AA64SMFR0, I16I64, 52, 4)
+FIELD(ID_AA64SMFR0, SMEVER, 56, 4)
+FIELD(ID_AA64SMFR0, FA64, 63, 1)
+
 FIELD(ID_DFR0, COPDBG, 0, 4)
 FIELD(ID_DFR0, COPSDBG, 4, 4)
 FIELD(ID_DFR0, MMAPDBG, 8, 4)
@@ -4195,6 +4205,21 @@ static inline bool isar_feature_aa64_sve_f64mm(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64zfr0, ID_AA64ZFR0, F64MM) != 0;
 }
 
+static inline bool isar_feature_aa64_sme_f64f64(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64smfr0, ID_AA64SMFR0, F64F64);
+}
+
+static inline bool isar_feature_aa64_sme_i16i64(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64smfr0, ID_AA64SMFR0, I16I64) == 0xf;
+}
+
+static inline bool isar_feature_aa64_sme_fa64(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64smfr0, ID_AA64SMFR0, FA64);
+}
+
 /*
  * Feature tests for "does this exist in either 32-bit or 64-bit?"
  */
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 400f7cd..ac9942d 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -7722,11 +7722,11 @@ void register_cp_regs_for_features(ARMCPU *cpu)
               .access = PL1_R, .type = ARM_CP_CONST,
               .accessfn = access_aa64_tid3,
               .resetvalue = cpu->isar.id_aa64zfr0 },
-            { .name = "ID_AA64PFR5_EL1_RESERVED", .state = ARM_CP_STATE_AA64,
+            { .name = "ID_AA64SMFR0_EL1", .state = ARM_CP_STATE_AA64,
               .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 4, .opc2 = 5,
               .access = PL1_R, .type = ARM_CP_CONST,
               .accessfn = access_aa64_tid3,
-              .resetvalue = 0 },
+              .resetvalue = cpu->isar.id_aa64smfr0 },
             { .name = "ID_AA64PFR6_EL1_RESERVED", .state = ARM_CP_STATE_AA64,
               .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 4, .opc2 = 6,
               .access = PL1_R, .type = ARM_CP_CONST,
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index b3f635f..ff8f65d 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -574,6 +574,8 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
     } else {
         err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64pfr1,
                               ARM64_SYS_REG(3, 0, 0, 4, 1));
+        err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64smfr0,
+                              ARM64_SYS_REG(3, 0, 0, 4, 5));
         err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64dfr0,
                               ARM64_SYS_REG(3, 0, 0, 5, 0));
         err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64dfr1,
@@ -682,10 +684,11 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
         ahcf->isar.id_aa64pfr0 = t;
 
         /*
-         * Before v5.1, KVM did not support SVE and did not expose
-         * ID_AA64ZFR0_EL1 even as RAZ.  After v5.1, KVM still does
-         * not expose the register to "user" requests like this
-         * unless the host supports SVE.
+         * There is a range of kernels between kernel commit 73433762fcae
+         * and f81cb2c3ad41 which have a bug where the kernel doesn't expose
+         * SYS_ID_AA64ZFR0_EL1 via the ONE_REG API unless the VM has enabled
+         * SVE support, so we only read it here, rather than together with all
+         * the other ID registers earlier.
          */
         err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64zfr0,
                               ARM64_SYS_REG(3, 0, 0, 4, 4));