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From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: qemu-devel@nongnu.org
Cc: qemu-arm@nongnu.org,
	"Mohamed Mediouni" <mohamed@unpredictable.fr>,
	"Phil Dennis-Jordan" <phil@philjordan.eu>,
	"Roman Bolshakov" <rbolshakov@ddn.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Alexander Graf" <agraf@csgraf.de>,
	"Mads Ynddal" <mads@ynddal.dk>,
	"Cameron Esfahani" <dirty@apple.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>
Subject: [PATCH-for-10.1 v4 4/4] target/arm/hvf: Really set Generic Timer counter frequency
Date: Wed, 23 Jul 2025 15:51:56 +0200	[thread overview]
Message-ID: <20250723135156.85426-5-philmd@linaro.org> (raw)
In-Reply-To: <20250723135156.85426-1-philmd@linaro.org>

Setting ARMCPU::gt_cntfrq_hz in hvf_arch_init_vcpu() is
not correct because the timers have already be initialized
with the default frequency.

Set it earlier in the AccelOpsClass::cpu_target_realize()
handler instead, and assert the value is correct when
reaching hvf_arch_init_vcpu().

Fixes: a1477da3dde ("hvf: Add Apple Silicon support")
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/hvf/hvf.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index 7de770da4f3..ea9e6b1c0c6 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -1007,6 +1007,13 @@ cleanup:
     return ret;
 }
 
+static uint64_t get_cntfrq_el0(void)
+{
+    uint64_t freq_hz = 0;
+    asm volatile("mrs %0, cntfrq_el0" : "=r"(freq_hz));
+    return freq_hz;
+}
+
 int hvf_arch_init_vcpu(CPUState *cpu)
 {
     ARMCPU *arm_cpu = ARM_CPU(cpu);
@@ -1018,7 +1025,9 @@ int hvf_arch_init_vcpu(CPUState *cpu)
     int i;
 
     env->aarch64 = true;
-    asm volatile("mrs %0, cntfrq_el0" : "=r"(arm_cpu->gt_cntfrq_hz));
+
+    /* system count frequency sanity check */
+    assert(arm_cpu->gt_cntfrq_hz == get_cntfrq_el0());
 
     /* Allocate enough space for our sysreg sync */
     arm_cpu->cpreg_indexes = g_renew(uint64_t, arm_cpu->cpreg_indexes,
@@ -1083,6 +1092,10 @@ int hvf_arch_init_vcpu(CPUState *cpu)
 
 bool hvf_arch_cpu_realize(CPUState *cs, Error **errp)
 {
+    ARMCPU *cpu = ARM_CPU(cs);
+
+    cpu->gt_cntfrq_hz = get_cntfrq_el0();
+
     return true;
 }
 
-- 
2.49.0



  parent reply	other threads:[~2025-07-23 13:58 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-23 13:51 [PATCH-for-10.1 v4 0/4] target/arm/hvf: Correctly set Generic Timer frequency Philippe Mathieu-Daudé
2025-07-23 13:51 ` [PATCH-for-10.1 v4 1/4] accel: Introduce AccelOpsClass::cpu_target_realize() hook Philippe Mathieu-Daudé
2025-07-23 15:49   ` Peter Maydell
2025-07-23 16:18     ` Philippe Mathieu-Daudé
2025-07-23 13:51 ` [PATCH-for-10.1 v4 2/4] accel/hvf: Add hvf_arch_cpu_realize() stubs Philippe Mathieu-Daudé
2025-07-23 16:06   ` Peter Maydell
2025-07-23 13:51 ` [PATCH-for-10.1 v4 3/4] target/arm: Create GTimers *after* features finalized / accel realized Philippe Mathieu-Daudé
2025-07-23 16:00   ` Peter Maydell
2025-07-23 16:19     ` Philippe Mathieu-Daudé
2025-07-23 13:51 ` Philippe Mathieu-Daudé [this message]
2025-07-23 16:06   ` [PATCH-for-10.1 v4 4/4] target/arm/hvf: Really set Generic Timer counter frequency Peter Maydell

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