[PULL 43/49] hvf: gate ARM_FEATURE_PMU register emulation behind not being at EL2

Maintainers: "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Thomas Huth <thuth@redhat.com>, Cameron Esfahani <dirty@apple.com>, Roman Bolshakov <rbolshakov@ddn.com>, Phil Dennis-Jordan <phil@philjordan.eu>, Yi Liu <yi.l.liu@intel.com>, Eric Auger <eric.auger@redhat.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Pierrick Bouvier <pierrick.bouvier@linaro.org>, Peter Maydell <peter.maydell@linaro.org>, "Cédric Le Goater" <clg@kaod.org>, Steven Lee <steven_lee@aspeedtech.com>, Troy Lee <leetroy@gmail.com>, Jamin Lin <jamin_lin@aspeedtech.com>, Andrew Jeffery <andrew@codeconstruct.com.au>, Joel Stanley <joel@jms.id.au>, Jason Wang <jasowang@redhat.com>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Laurent Vivier <lvivier@redhat.com>, Alexander Graf <agraf@csgraf.de>, Pedro Barbuda <pbarbuda@microsoft.com>, Mohamed Mediouni <mohamed@unpredictable.fr>, Alexander Bulekov <alxndr@bu.edu>, Stefan Hajnoczi <stefanha@redhat.com>, Darren Kenny <darren.kenny@oracle.com>, Qiuhao Li <Qiuhao.Li@outlook.com>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
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[PULL 43/49] hvf: gate ARM_FEATURE_PMU register emulation behind not being at EL2
Posted by Peter Maydell 1 month, 1 week ago
From: Mohamed Mediouni <mohamed@unpredictable.fr>

From Apple documentation:

> When EL2 is disabled, PMU register accesses trigger "Trapped MSR, MRS, or
> System Instruction" exceptions. When this happens, hv_vcpu_run() returns, and the
>  hv_vcpu_exit_t object contains the information about this exception.

> When EL2 is enabled, the handling of PMU register accesses is determined by the PMUVer
> field of ID_AA64DFR0_EL1 register.
> If the PMUVer field value is zero or is invalid, PMU register accesses generate "Undefined"
> exceptions, which are sent to the guest.
> If the PMUVer field value is non-zero and valid, PMU register accesses are emulated by the framework.
> The ID_AA64DFR0_EL1 register can be modified via hv_vcpu_set_sys_reg API.

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20260306130107.35359-12-mohamed@unpredictable.fr
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/hvf/hvf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index 8363e10eff..91bbb2013b 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -1589,7 +1589,7 @@ static int hvf_sysreg_read(CPUState *cpu, uint32_t reg, uint64_t *val)
     ARMCPU *arm_cpu = ARM_CPU(cpu);
     CPUARMState *env = &arm_cpu->env;
 
-    if (arm_feature(env, ARM_FEATURE_PMU)) {
+    if (!hvf_nested_virt_enabled() && arm_feature(env, ARM_FEATURE_PMU)) {
         switch (reg) {
         case SYSREG_PMCR_EL0:
             *val = env->cp15.c9_pmcr;
@@ -1850,7 +1850,7 @@ static int hvf_sysreg_write(CPUState *cpu, uint32_t reg, uint64_t val)
                            SYSREG_OP2(reg),
                            val);
 
-    if (arm_feature(env, ARM_FEATURE_PMU)) {
+    if (!hvf_nested_virt_enabled() && arm_feature(env, ARM_FEATURE_PMU)) {
         switch (reg) {
         case SYSREG_PMCCNTR_EL0:
             pmu_op_start(env);
-- 
2.43.0