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[Qemu-devel] [PULL 14/25] target/arm: Query host CPU features on-demand
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PULL 14/25] target/arm: Query host CPU features on-demand at instance init |
Date: |
Fri, 9 Mar 2018 17:26:11 +0000 |
Currently we query the host CPU features in the class init function
for the TYPE_ARM_HOST_CPU class, so that we can later copy them
from the class object into the instance object in the object
instance init function. This is awkward for implementing "-cpu max",
which should work like "-cpu host" for KVM but like "cpu with all
implemented features" for TCG.
Move the place where we store the information about the host CPU from
a class object to static variables in kvm.c, and then in the instance
init function call a new kvm_arm_set_cpu_features_from_host()
function which will query the host kernel if necessary and then
fill in the CPU instance fields.
This allows us to drop the special class struct and class init
function for TYPE_ARM_HOST_CPU entirely.
We can't delay the probe until realize, because the ARM
instance_post_init hook needs to look at the feature bits we
set, so we need to do it in the initfn. This is safe because
the probing doesn't affect the actual VM state (it creates a
separate scratch VM to do its testing), but the probe might fail.
Because we can't report errors in retrieving the host features
in the initfn, we check this belatedly in the realize function
(the intervening code will be able to cope with the relevant
fields in the CPU structure being zero).
Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
Message-id: address@hidden
---
target/arm/cpu.h | 5 +++++
target/arm/kvm_arm.h | 35 ++++++++++++++++++++++++-----------
target/arm/cpu.c | 13 +++++++++++++
target/arm/kvm.c | 36 +++++++++++++++++++-----------------
target/arm/kvm32.c | 8 ++++----
target/arm/kvm64.c | 8 ++++----
6 files changed, 69 insertions(+), 36 deletions(-)
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 36711cdb50..1e7e1f8a7e 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -745,6 +745,11 @@ struct ARMCPU {
/* Uniprocessor system with MP extensions */
bool mp_is_up;
+ /* True if we tried kvm_arm_host_cpu_features() during CPU instance_init
+ * and the probe failed (so we need to report the error in realize)
+ */
+ bool host_cpu_probe_failed;
+
/* Specify the number of cores in this CPU cluster. Used for the L2CTLR
* register.
*/
diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index cfb7e5af72..1e2364007d 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -152,20 +152,16 @@ bool kvm_arm_create_scratch_host_vcpu(const uint32_t
*cpus_to_try,
void kvm_arm_destroy_scratch_host_vcpu(int *fdarray);
#define TYPE_ARM_HOST_CPU "host-" TYPE_ARM_CPU
-#define ARM_HOST_CPU_CLASS(klass) \
- OBJECT_CLASS_CHECK(ARMHostCPUClass, (klass), TYPE_ARM_HOST_CPU)
-#define ARM_HOST_CPU_GET_CLASS(obj) \
- OBJECT_GET_CLASS(ARMHostCPUClass, (obj), TYPE_ARM_HOST_CPU)
-
-typedef struct ARMHostCPUClass {
- /*< private >*/
- ARMCPUClass parent_class;
- /*< public >*/
+/**
+ * ARMHostCPUFeatures: information about the host CPU (identified
+ * by asking the host kernel)
+ */
+typedef struct ARMHostCPUFeatures {
uint64_t features;
uint32_t target;
const char *dtb_compatible;
-} ARMHostCPUClass;
+} ARMHostCPUFeatures;
/**
* kvm_arm_get_host_cpu_features:
@@ -174,8 +170,16 @@ typedef struct ARMHostCPUClass {
* Probe the capabilities of the host kernel's preferred CPU and fill
* in the ARMHostCPUClass struct accordingly.
*/
-bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc);
+bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf);
+/**
+ * kvm_arm_set_cpu_features_from_host:
+ * @cpu: ARMCPU to set the features for
+ *
+ * Set up the ARMCPU struct fields up to match the information probed
+ * from the host CPU.
+ */
+void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu);
/**
* kvm_arm_sync_mpstate_to_kvm
@@ -200,6 +204,15 @@ void kvm_arm_pmu_init(CPUState *cs);
#else
+static inline void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
+{
+ /* This should never actually be called in the "not KVM" case,
+ * but set up the fields to indicate an error anyway.
+ */
+ cpu->kvm_target = QEMU_KVM_ARM_TARGET_NONE;
+ cpu->host_cpu_probe_failed = true;
+}
+
static inline int kvm_arm_vgic_probe(void)
{
return 0;
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 3e4e9f1873..5809225a36 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -725,6 +725,19 @@ static void arm_cpu_realizefn(DeviceState *dev, Error
**errp)
int pagebits;
Error *local_err = NULL;
+ /* If we needed to query the host kernel for the CPU features
+ * then it's possible that might have failed in the initfn, but
+ * this is the first point where we can report it.
+ */
+ if (cpu->host_cpu_probe_failed) {
+ if (!kvm_enabled()) {
+ error_setg(errp, "The 'host' CPU type can only be used with KVM");
+ } else {
+ error_setg(errp, "Failed to retrieve host CPU features");
+ }
+ return;
+ }
+
cpu_exec_realizefn(cs, &local_err);
if (local_err != NULL) {
error_propagate(errp, local_err);
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 1219d0062b..1c0e57690a 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -33,6 +33,8 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
static bool cap_has_mp_state;
+static ARMHostCPUFeatures arm_host_cpu_features;
+
int kvm_arm_vcpu_init(CPUState *cs)
{
ARMCPU *cpu = ARM_CPU(cs);
@@ -129,30 +131,32 @@ void kvm_arm_destroy_scratch_host_vcpu(int *fdarray)
}
}
-static void kvm_arm_host_cpu_class_init(ObjectClass *oc, void *data)
+void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
{
- ARMHostCPUClass *ahcc = ARM_HOST_CPU_CLASS(oc);
+ CPUARMState *env = &cpu->env;
- /* All we really need to set up for the 'host' CPU
- * is the feature bits -- we rely on the fact that the
- * various ID register values in ARMCPU are only used for
- * TCG CPUs.
- */
- if (!kvm_arm_get_host_cpu_features(ahcc)) {
- fprintf(stderr, "Failed to retrieve host CPU features!\n");
- abort();
+ if (!arm_host_cpu_features.dtb_compatible) {
+ if (!kvm_enabled() ||
+ !kvm_arm_get_host_cpu_features(&arm_host_cpu_features)) {
+ /* We can't report this error yet, so flag that we need to
+ * in arm_cpu_realizefn().
+ */
+ cpu->kvm_target = QEMU_KVM_ARM_TARGET_NONE;
+ cpu->host_cpu_probe_failed = true;
+ return;
+ }
}
+
+ cpu->kvm_target = arm_host_cpu_features.target;
+ cpu->dtb_compatible = arm_host_cpu_features.dtb_compatible;
+ env->features = arm_host_cpu_features.features;
}
static void kvm_arm_host_cpu_initfn(Object *obj)
{
- ARMHostCPUClass *ahcc = ARM_HOST_CPU_GET_CLASS(obj);
ARMCPU *cpu = ARM_CPU(obj);
- CPUARMState *env = &cpu->env;
- cpu->kvm_target = ahcc->target;
- cpu->dtb_compatible = ahcc->dtb_compatible;
- env->features = ahcc->features;
+ kvm_arm_set_cpu_features_from_host(cpu);
}
static const TypeInfo host_arm_cpu_type_info = {
@@ -163,8 +167,6 @@ static const TypeInfo host_arm_cpu_type_info = {
.parent = TYPE_ARM_CPU,
#endif
.instance_init = kvm_arm_host_cpu_initfn,
- .class_init = kvm_arm_host_cpu_class_init,
- .class_size = sizeof(ARMHostCPUClass),
};
int kvm_arch_init(MachineState *ms, KVMState *s)
diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c
index f77c9c494b..1740cda47d 100644
--- a/target/arm/kvm32.c
+++ b/target/arm/kvm32.c
@@ -28,7 +28,7 @@ static inline void set_feature(uint64_t *features, int
feature)
*features |= 1ULL << feature;
}
-bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
+bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
{
/* Identify the feature bits corresponding to the host CPU, and
* fill out the ARMHostCPUClass fields accordingly. To do this
@@ -74,13 +74,13 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
return false;
}
- ahcc->target = init.target;
+ ahcf->target = init.target;
/* This is not strictly blessed by the device tree binding docs yet,
* but in practice the kernel does not care about this string so
* there is no point maintaining an KVM_ARM_TARGET_* -> string table.
*/
- ahcc->dtb_compatible = "arm,arm-v7";
+ ahcf->dtb_compatible = "arm,arm-v7";
for (i = 0; i < ARRAY_SIZE(idregs); i++) {
ret = ioctl(fdarray[2], KVM_GET_ONE_REG, &idregs[i]);
@@ -132,7 +132,7 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
set_feature(&features, ARM_FEATURE_VFP4);
}
- ahcc->features = features;
+ ahcf->features = features;
return true;
}
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index ac728494a4..e0b8246283 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -443,7 +443,7 @@ static inline void unset_feature(uint64_t *features, int
feature)
*features &= ~(1ULL << feature);
}
-bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
+bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
{
/* Identify the feature bits corresponding to the host CPU, and
* fill out the ARMHostCPUClass fields accordingly. To do this
@@ -471,8 +471,8 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
return false;
}
- ahcc->target = init.target;
- ahcc->dtb_compatible = "arm,arm-v8";
+ ahcf->target = init.target;
+ ahcf->dtb_compatible = "arm,arm-v8";
kvm_arm_destroy_scratch_host_vcpu(fdarray);
@@ -486,7 +486,7 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
set_feature(&features, ARM_FEATURE_AARCH64);
set_feature(&features, ARM_FEATURE_PMU);
- ahcc->features = features;
+ ahcf->features = features;
return true;
}
--
2.16.2
- [Qemu-devel] [PULL 09/25] aarch64-linux-user: Add support for EXTRA signal frame records, (continued)
- [Qemu-devel] [PULL 09/25] aarch64-linux-user: Add support for EXTRA signal frame records, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 19/25] hw/arm/virt: Support -machine gic-version=max, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 16/25] target/arm: Add "-cpu max" support, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 08/25] aarch64-linux-user: Remove struct target_aux_context, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 06/25] linux-user: Implement aarch64 PR_SVE_SET/GET_VL, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 07/25] aarch64-linux-user: Split out helpers for guest signal handling, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 02/25] hw/arm: Set the core count for Xilinx's ZynqMP, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 22/25] sdcard: Display which protocol is used when tracing (SD or SPI), Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 21/25] sdcard: Display command name when tracing CMD/ACMD, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 01/25] target/arm: Add a core count property, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 14/25] target/arm: Query host CPU features on-demand at instance init,
Peter Maydell <=
- [Qemu-devel] [PULL 05/25] Implement support for i.MX7 Sabre board, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 18/25] hw/arm/virt: Add "max" to the list of CPU types "virt" supports, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 03/25] pci: Add support for Designware IP block, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 17/25] target/arm: Make 'any' CPU just an alias for 'max', Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 20/25] sdcard: Do not trace CMD55, except when we already expect an ACMD, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 24/25] sdhci: Fix a typo in comment, Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 25/25] MAINTAINERS: Add entries for SD (SDHCI, SDBus, SDCard), Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 04/25] i.MX: Add i.MX7 SOC implementation., Peter Maydell, 2018/03/09
- [Qemu-devel] [PULL 23/25] sdcard: Add the Tuning Command (CMD19), Peter Maydell, 2018/03/09
- Re: [Qemu-devel] [PULL 00/25] target-arm queue, Peter Maydell, 2018/03/12