[PATCH v2 16/58] target/arm/hvf: switch hvf_arm_get_host_cpu_features to not create a vCPU

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

From: Mohamed Mediouni <mohamed@unpredictable.fr>

Creating a vCPU locks out APIs such as hv_gic_create().

As a result, switch to using the hv_vcpu_config_get_feature_reg interface.

Besides, all the following methods must be run on a vCPU thread:

  - hv_vcpu_create()
  - hv_vcpu_get_sys_reg()
  - hv_vcpu_destroy()

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Mads Ynddal <mads@ynddal.dk>
Message-ID: <20250808070137.48716-3-mohamed@unpredictable.fr>
[PMD: Release config calling os_release()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/arm/hvf/hvf.c | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index dea1cb37d1f..fcb6950692b 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -744,25 +744,24 @@ static bool hvf_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
 {
     ARMISARegisters host_isar = {};
     static const struct isar_regs {
-        int reg;
+        hv_feature_reg_t reg;
         ARMIDRegisterIdx index;
     } regs[] = {
-        { HV_SYS_REG_ID_AA64PFR0_EL1, ID_AA64PFR0_EL1_IDX },
-        { HV_SYS_REG_ID_AA64PFR1_EL1, ID_AA64PFR1_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64PFR0_EL1, ID_AA64PFR0_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64PFR1_EL1, ID_AA64PFR1_EL1_IDX },
         /* Add ID_AA64PFR2_EL1 here when HVF supports it */
-        { HV_SYS_REG_ID_AA64DFR0_EL1, ID_AA64DFR0_EL1_IDX },
-        { HV_SYS_REG_ID_AA64DFR1_EL1, ID_AA64DFR1_EL1_IDX },
-        { HV_SYS_REG_ID_AA64ISAR0_EL1, ID_AA64ISAR0_EL1_IDX },
-        { HV_SYS_REG_ID_AA64ISAR1_EL1, ID_AA64ISAR1_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64DFR0_EL1, ID_AA64DFR0_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64DFR1_EL1, ID_AA64DFR1_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64ISAR0_EL1, ID_AA64ISAR0_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64ISAR1_EL1, ID_AA64ISAR1_EL1_IDX },
         /* Add ID_AA64ISAR2_EL1 here when HVF supports it */
-        { HV_SYS_REG_ID_AA64MMFR0_EL1, ID_AA64MMFR0_EL1_IDX },
-        { HV_SYS_REG_ID_AA64MMFR1_EL1, ID_AA64MMFR1_EL1_IDX },
-        { HV_SYS_REG_ID_AA64MMFR2_EL1, ID_AA64MMFR2_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64MMFR0_EL1, ID_AA64MMFR0_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64MMFR1_EL1, ID_AA64MMFR1_EL1_IDX },
+        { HV_FEATURE_REG_ID_AA64MMFR2_EL1, ID_AA64MMFR2_EL1_IDX },
         /* Add ID_AA64MMFR3_EL1 here when HVF supports it */
     };
-    hv_vcpu_t fd;
     hv_return_t r = HV_SUCCESS;
-    hv_vcpu_exit_t *exit;
+    hv_vcpu_config_t config = hv_vcpu_config_create();
     uint64_t t;
     int i;
 
@@ -773,17 +772,11 @@ static bool hvf_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
                      (1ULL << ARM_FEATURE_PMU) |
                      (1ULL << ARM_FEATURE_GENERIC_TIMER);
 
-    /* We set up a small vcpu to extract host registers */
-
-    if (hv_vcpu_create(&fd, &exit, NULL) != HV_SUCCESS) {
-        return false;
-    }
-
     for (i = 0; i < ARRAY_SIZE(regs); i++) {
-        r |= hv_vcpu_get_sys_reg(fd, regs[i].reg,
-                                 &host_isar.idregs[regs[i].index]);
+        r |= hv_vcpu_config_get_feature_reg(config, regs[i].reg,
+                                            &host_isar.idregs[regs[i].index]);
     }
-    r |= hv_vcpu_destroy(fd);
+    os_release(config);
 
     /*
      * Hardcode MIDR because Apple deliberately doesn't expose a divergent
-- 
2.51.0