[PATCH V2 4/5] kvm/stats: Add provisioning for 64-bit vcpu statistics

[David Matlack]

On Mon, Jul 11, 2016 at 12:08 AM, Suraj Jitindar Singh
<sjitindarsingh at gmail.com> wrote:
> vcpus have statistics associated with them which can be viewed within the
> debugfs. Currently it is assumed within the vcpu_stat_get() and
> vcpu_stat_get_per_vm() functions that all of these statistics are
> represented as 32-bit numbers. The next patch adds some 64-bit statistics,
> so add provisioning for the display of 64-bit vcpu statistics.

Thanks, we need 64-bit stats in other places as well. Can we use this
opportunity to wholesale upgrade all KVM stats from u32 to u64? Most
of this patch is duplicated code with "u32" swapped with "u64".

>
> ---
> Change Log:
>
> V1 -> V2:
>         - Nothing
>
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh at gmail.com>
> ---
>  arch/powerpc/kvm/book3s.c |  1 +
>  include/linux/kvm_host.h  |  1 +
>  virt/kvm/kvm_main.c       | 60 +++++++++++++++++++++++++++++++++++++++++++----
>  3 files changed, 58 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
> index 47018fc..ed9132b 100644
> --- a/arch/powerpc/kvm/book3s.c
> +++ b/arch/powerpc/kvm/book3s.c
> @@ -40,6 +40,7 @@
>  #include "trace.h"
>
>  #define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
> +#define VCPU_STAT_U64(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU_U64
>
>  /* #define EXIT_DEBUG */
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 1c9c973..667b30e 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -991,6 +991,7 @@ static inline bool kvm_is_error_gpa(struct kvm *kvm, gpa_t gpa)
>  enum kvm_stat_kind {
>         KVM_STAT_VM,
>         KVM_STAT_VCPU,
> +       KVM_STAT_VCPU_U64,
>  };
>
>  struct kvm_stat_data {
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 48bd520..7ab5901 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3566,6 +3566,20 @@ static int vcpu_stat_get_per_vm(void *data, u64 *val)
>         return 0;
>  }
>
> +static int vcpu_stat_u64_get_per_vm(void *data, u64 *val)
> +{
> +       int i;
> +       struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
> +       struct kvm_vcpu *vcpu;
> +
> +       *val = 0;
> +
> +       kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
> +               *val += *(u64 *)((void *)vcpu + stat_data->offset);
> +
> +       return 0;
> +}
> +
>  static int vcpu_stat_get_per_vm_open(struct inode *inode, struct file *file)
>  {
>         __simple_attr_check_format("%llu\n", 0ull);
> @@ -3573,6 +3587,13 @@ static int vcpu_stat_get_per_vm_open(struct inode *inode, struct file *file)
>                                  NULL, "%llu\n");
>  }
>
> +static int vcpu_stat_u64_get_per_vm_open(struct inode *inode, struct file *file)
> +{
> +       __simple_attr_check_format("%llu\n", 0ull);
> +       return kvm_debugfs_open(inode, file, vcpu_stat_u64_get_per_vm,
> +                                NULL, "%llu\n");
> +}
> +
>  static const struct file_operations vcpu_stat_get_per_vm_fops = {
>         .owner   = THIS_MODULE,
>         .open    = vcpu_stat_get_per_vm_open,
> @@ -3582,9 +3603,19 @@ static const struct file_operations vcpu_stat_get_per_vm_fops = {
>         .llseek  = generic_file_llseek,
>  };
>
> +static const struct file_operations vcpu_stat_u64_get_per_vm_fops = {
> +       .owner   = THIS_MODULE,
> +       .open    = vcpu_stat_u64_get_per_vm_open,
> +       .release = kvm_debugfs_release,
> +       .read    = simple_attr_read,
> +       .write   = simple_attr_write,
> +       .llseek  = generic_file_llseek,
> +};
> +
>  static const struct file_operations *stat_fops_per_vm[] = {
> -       [KVM_STAT_VCPU] = &vcpu_stat_get_per_vm_fops,
> -       [KVM_STAT_VM]   = &vm_stat_get_per_vm_fops,
> +       [KVM_STAT_VCPU]         = &vcpu_stat_get_per_vm_fops,
> +       [KVM_STAT_VCPU_U64]     = &vcpu_stat_u64_get_per_vm_fops,
> +       [KVM_STAT_VM]           = &vm_stat_get_per_vm_fops,
>  };
>
>  static int vm_stat_get(void *_offset, u64 *val)
> @@ -3627,9 +3658,30 @@ static int vcpu_stat_get(void *_offset, u64 *val)
>
>  DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, NULL, "%llu\n");
>
> +static int vcpu_stat_u64_get(void *_offset, u64 *val)
> +{
> +       unsigned offset = (long)_offset;
> +       struct kvm *kvm;
> +       struct kvm_stat_data stat_tmp = {.offset = offset};
> +       u64 tmp_val;
> +
> +       *val = 0;
> +       spin_lock(&kvm_lock);
> +       list_for_each_entry(kvm, &vm_list, vm_list) {
> +               stat_tmp.kvm = kvm;
> +               vcpu_stat_u64_get_per_vm((void *)&stat_tmp, &tmp_val);
> +               *val += tmp_val;
> +       }
> +       spin_unlock(&kvm_lock);
> +       return 0;
> +}
> +
> +DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_u64_fops, vcpu_stat_u64_get, NULL, "%llu\n");
> +
>  static const struct file_operations *stat_fops[] = {
> -       [KVM_STAT_VCPU] = &vcpu_stat_fops,
> -       [KVM_STAT_VM]   = &vm_stat_fops,
> +       [KVM_STAT_VCPU]         = &vcpu_stat_fops,
> +       [KVM_STAT_VCPU_U64]     = &vcpu_stat_u64_fops,
> +       [KVM_STAT_VM]           = &vm_stat_fops,
>  };
>
>  static int kvm_init_debug(void)
> --
> 2.5.5
>
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