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.

Hardcode MIDR because Apple deliberately doesn't expose a divergent MIDR across systems.

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
---
 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 47b0cd3a35..5ee0df17e3 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -864,24 +864,24 @@ static bool hvf_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
 {
     ARMISARegisters host_isar = {};
     const struct isar_regs {
-        int reg;
+        hv_feature_reg_t reg;
         uint64_t *val;
     } regs[] = {
-        { HV_SYS_REG_ID_AA64PFR0_EL1, &host_isar.idregs[ID_AA64PFR0_EL1_IDX] },
-        { HV_SYS_REG_ID_AA64PFR1_EL1, &host_isar.idregs[ID_AA64PFR1_EL1_IDX] },
-        { HV_SYS_REG_ID_AA64DFR0_EL1, &host_isar.idregs[ID_AA64DFR0_EL1_IDX] },
-        { HV_SYS_REG_ID_AA64DFR1_EL1, &host_isar.idregs[ID_AA64DFR1_EL1_IDX] },
-        { HV_SYS_REG_ID_AA64ISAR0_EL1, &host_isar.idregs[ID_AA64ISAR0_EL1_IDX] },
-        { HV_SYS_REG_ID_AA64ISAR1_EL1, &host_isar.idregs[ID_AA64ISAR1_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64PFR0_EL1, &host_isar.idregs[ID_AA64PFR0_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64PFR1_EL1, &host_isar.idregs[ID_AA64PFR1_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64DFR0_EL1, &host_isar.idregs[ID_AA64DFR0_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64DFR1_EL1, &host_isar.idregs[ID_AA64DFR1_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64ISAR0_EL1, &host_isar.idregs[ID_AA64ISAR0_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64ISAR1_EL1, &host_isar.idregs[ID_AA64ISAR1_EL1_IDX] },
         /* Add ID_AA64ISAR2_EL1 here when HVF supports it */
-        { HV_SYS_REG_ID_AA64MMFR0_EL1, &host_isar.idregs[ID_AA64MMFR0_EL1_IDX] },
-        { HV_SYS_REG_ID_AA64MMFR1_EL1, &host_isar.idregs[ID_AA64MMFR1_EL1_IDX] },
-        { HV_SYS_REG_ID_AA64MMFR2_EL1, &host_isar.idregs[ID_AA64MMFR2_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64MMFR0_EL1, &host_isar.idregs[ID_AA64MMFR0_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64MMFR1_EL1, &host_isar.idregs[ID_AA64MMFR1_EL1_IDX] },
+        { HV_FEATURE_REG_ID_AA64MMFR2_EL1, &host_isar.idregs[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 hv_vcpu_config = hv_vcpu_config_create();
     int i;
 
     ahcf->dtb_compatible = "arm,armv8";
@@ -891,17 +891,10 @@ 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, regs[i].val);
+        r |= hv_vcpu_config_get_feature_reg(hv_vcpu_config, regs[i].reg, regs[i].val);
     }
-    r |= hv_vcpu_get_sys_reg(fd, HV_SYS_REG_MIDR_EL1, &ahcf->midr);
-    r |= hv_vcpu_destroy(fd);
+    ahcf->midr = 0x610f0000;
 
     clamp_id_aa64mmfr0_parange_to_ipa_size(&host_isar);
 
-- 
2.39.5 (Apple Git-154)

Hi Mohamed,

On 28/7/25 15:41, Mohamed Mediouni wrote:
> 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.
> 
> Hardcode MIDR because Apple deliberately doesn't expose a divergent MIDR across systems.
> 
> Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
> ---
>   target/arm/hvf/hvf.c | 35 ++++++++++++++---------------------
>   1 file changed, 14 insertions(+), 21 deletions(-)


> @@ -891,17 +891,10 @@ 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, regs[i].val);
> +        r |= hv_vcpu_config_get_feature_reg(hv_vcpu_config, regs[i].reg, regs[i].val);
>       }
> -    r |= hv_vcpu_get_sys_reg(fd, HV_SYS_REG_MIDR_EL1, &ahcf->midr);
> -    r |= hv_vcpu_destroy(fd);
Could we add a comment explaining this magic value?

> +    ahcf->midr = 0x610f0000;

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>