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[Qemu-devel] [PATCH v6 07/18] kvm: add kvm_arm_get_max_vm_phys_shift

Eric Auger posted 18 patches 7 years ago
There is a newer version of this series
[Qemu-devel] [PATCH v6 07/18] kvm: add kvm_arm_get_max_vm_phys_shift
Posted by Eric Auger 7 years ago 
Add the kvm_arm_get_max_vm_phys_shift() helper that returns the
log of the maximum IPA size supported by KVM. This capability
needs to be known to create the VM with a specific IPA max size
(kvm_type passed along KVM_CREATE_VM ioctl.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---
v4 -> v5:
- return 40 if the host does not support the capability

v3 -> v4:
- s/s/ms in kvm_arm_get_max_vm_phys_shift function comment
- check KVM_CAP_ARM_VM_IPA_SIZE extension

v1 -> v2:
- put this in ARM specific code
---
 target/arm/kvm.c     | 10 ++++++++++
 target/arm/kvm_arm.h | 13 +++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index e00ccf9c98..fc1dd3ec6a 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -18,6 +18,7 @@
 #include "qemu/error-report.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/kvm.h"
+#include "sysemu/kvm_int.h"
 #include "kvm_arm.h"
 #include "cpu.h"
 #include "trace.h"
@@ -162,6 +163,15 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
     env->features = arm_host_cpu_features.features;
 }
 
+int kvm_arm_get_max_vm_phys_shift(MachineState *ms)
+{
+    KVMState *s = KVM_STATE(ms->accelerator);
+    int ret;
+
+    ret = kvm_check_extension(s, KVM_CAP_ARM_VM_IPA_SIZE);
+    return ret > 0 ? ret : 40;
+}
+
 int kvm_arch_init(MachineState *ms, KVMState *s)
 {
     /* For ARM interrupt delivery is always asynchronous,
diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index 6393455b1d..0728bbfa6b 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -207,6 +207,14 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf);
  */
 void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu);
 
+/**
+ * kvm_arm_get_max_vm_phys_shift - Returns log2 of the max IPA size
+ * supported by KVM
+ *
+ * @ms: Machine state handle
+ */
+int kvm_arm_get_max_vm_phys_shift(MachineState *ms);
+
 /**
  * kvm_arm_sync_mpstate_to_kvm
  * @cpu: ARMCPU
@@ -239,6 +247,11 @@ static inline void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
     cpu->host_cpu_probe_failed = true;
 }
 
+static inline int kvm_arm_get_max_vm_phys_shift(MachineState *ms)
+{
+    return -ENOENT;
+}
+
 static inline int kvm_arm_vgic_probe(void)
 {
     return 0;
-- 
2.20.1
Re: [Qemu-devel] [PATCH v6 07/18] kvm: add kvm_arm_get_max_vm_phys_shift
Posted by Peter Maydell 6 years, 11 months ago 
On Tue, 5 Feb 2019 at 17:33, Eric Auger <eric.auger@redhat.com> wrote:
>
> Add the kvm_arm_get_max_vm_phys_shift() helper that returns the
> log of the maximum IPA size supported by KVM. This capability
> needs to be known to create the VM with a specific IPA max size
> (kvm_type passed along KVM_CREATE_VM ioctl.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
> v4 -> v5:
> - return 40 if the host does not support the capability
>
> v3 -> v4:
> - s/s/ms in kvm_arm_get_max_vm_phys_shift function comment
> - check KVM_CAP_ARM_VM_IPA_SIZE extension
>
> v1 -> v2:
> - put this in ARM specific code
> ---
>  target/arm/kvm.c     | 10 ++++++++++
>  target/arm/kvm_arm.h | 13 +++++++++++++
>  2 files changed, 23 insertions(+)
>
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index e00ccf9c98..fc1dd3ec6a 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -18,6 +18,7 @@
>  #include "qemu/error-report.h"
>  #include "sysemu/sysemu.h"
>  #include "sysemu/kvm.h"
> +#include "sysemu/kvm_int.h"
>  #include "kvm_arm.h"
>  #include "cpu.h"
>  #include "trace.h"
> @@ -162,6 +163,15 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
>      env->features = arm_host_cpu_features.features;
>  }
>
> +int kvm_arm_get_max_vm_phys_shift(MachineState *ms)
> +{
> +    KVMState *s = KVM_STATE(ms->accelerator);
> +    int ret;
> +
> +    ret = kvm_check_extension(s, KVM_CAP_ARM_VM_IPA_SIZE);

Why not name the function the same as the extension name?

> +    return ret > 0 ? ret : 40;
> +}
> +
>  int kvm_arch_init(MachineState *ms, KVMState *s)
>  {
>      /* For ARM interrupt delivery is always asynchronous,
> diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
> index 6393455b1d..0728bbfa6b 100644
> --- a/target/arm/kvm_arm.h
> +++ b/target/arm/kvm_arm.h
> @@ -207,6 +207,14 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf);
>   */
>  void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu);
>
> +/**
> + * kvm_arm_get_max_vm_phys_shift - Returns log2 of the max IPA size
> + * supported by KVM

This is the number of bits in the IPA address space,
right (ie 40 for a 40-bit IPA, and so on) ? If so, then
I think "Return number of bits in the IPA address space"
might be clearer.

> + *
> + * @ms: Machine state handle
> + */
> +int kvm_arm_get_max_vm_phys_shift(MachineState *ms);

thanks
-- PMM
Re: [Qemu-devel] [PATCH v6 07/18] kvm: add kvm_arm_get_max_vm_phys_shift
Posted by Auger Eric 6 years, 11 months ago 
Hi Peter,
On 2/14/19 6:15 PM, Peter Maydell wrote:
> On Tue, 5 Feb 2019 at 17:33, Eric Auger <eric.auger@redhat.com> wrote:
>>
>> Add the kvm_arm_get_max_vm_phys_shift() helper that returns the
>> log of the maximum IPA size supported by KVM. This capability
>> needs to be known to create the VM with a specific IPA max size
>> (kvm_type passed along KVM_CREATE_VM ioctl.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>
>> ---
>> v4 -> v5:
>> - return 40 if the host does not support the capability
>>
>> v3 -> v4:
>> - s/s/ms in kvm_arm_get_max_vm_phys_shift function comment
>> - check KVM_CAP_ARM_VM_IPA_SIZE extension
>>
>> v1 -> v2:
>> - put this in ARM specific code
>> ---
>>  target/arm/kvm.c     | 10 ++++++++++
>>  target/arm/kvm_arm.h | 13 +++++++++++++
>>  2 files changed, 23 insertions(+)
>>
>> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
>> index e00ccf9c98..fc1dd3ec6a 100644
>> --- a/target/arm/kvm.c
>> +++ b/target/arm/kvm.c
>> @@ -18,6 +18,7 @@
>>  #include "qemu/error-report.h"
>>  #include "sysemu/sysemu.h"
>>  #include "sysemu/kvm.h"
>> +#include "sysemu/kvm_int.h"
>>  #include "kvm_arm.h"
>>  #include "cpu.h"
>>  #include "trace.h"
>> @@ -162,6 +163,15 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
>>      env->features = arm_host_cpu_features.features;
>>  }
>>
>> +int kvm_arm_get_max_vm_phys_shift(MachineState *ms)
>> +{
>> +    KVMState *s = KVM_STATE(ms->accelerator);
>> +    int ret;
>> +
>> +    ret = kvm_check_extension(s, KVM_CAP_ARM_VM_IPA_SIZE);
> 
> Why not name the function the same as the extension name?
> 
>> +    return ret > 0 ? ret : 40;
>> +}
>> +
>>  int kvm_arch_init(MachineState *ms, KVMState *s)
>>  {
>>      /* For ARM interrupt delivery is always asynchronous,
>> diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
>> index 6393455b1d..0728bbfa6b 100644
>> --- a/target/arm/kvm_arm.h
>> +++ b/target/arm/kvm_arm.h
>> @@ -207,6 +207,14 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf);
>>   */
>>  void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu);
>>
>> +/**
>> + * kvm_arm_get_max_vm_phys_shift - Returns log2 of the max IPA size
>> + * supported by KVM
> 
> This is the number of bits in the IPA address space,
> right (ie 40 for a 40-bit IPA, and so on) ? If so, then
> I think "Return number of bits in the IPA address space"
> might be clearer.

It actually returns the MAX number of bits in the IPA address space
supported by the host kernel. What about naming this function
"kvm_arm_get_max_vm_ipa_size".

Thanks

Eric
> 
>> + *
>> + * @ms: Machine state handle
>> + */
>> +int kvm_arm_get_max_vm_phys_shift(MachineState *ms);
> 
> thanks
> -- PMM
>

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