Hi, Bibo,
On Mon, May 27, 2024 at 3:46 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
>
> Before virt machine or vcpu is created, vmm need check supported
> features from KVM. Here ioctl command KVM_HAS_DEVICE_ATTR is added
> for VM, and macro KVM_LOONGARCH_VM_FEAT_CTRL is added to check
> supported feature.
>
> Three sub-features relative with LBT are added, in later any new
> feature can be added if it is used for vmm. The sub-features is
> KVM_LOONGARCH_VM_FEAT_X86BT
> KVM_LOONGARCH_VM_FEAT_ARMBT
> KVM_LOONGARCH_VM_FEAT_MIPSBT
>
> Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> ---
> arch/loongarch/include/uapi/asm/kvm.h | 6 ++++
> arch/loongarch/kvm/vm.c | 44 ++++++++++++++++++++++++++-
> 2 files changed, 49 insertions(+), 1 deletion(-)
>
> diff --git a/arch/loongarch/include/uapi/asm/kvm.h b/arch/loongarch/include/uapi/asm/kvm.h
> index 656aa6a723a6..ed12e509815c 100644
> --- a/arch/loongarch/include/uapi/asm/kvm.h
> +++ b/arch/loongarch/include/uapi/asm/kvm.h
> @@ -91,6 +91,12 @@ struct kvm_fpu {
> #define KVM_IOC_CSRID(REG) LOONGARCH_REG_64(KVM_REG_LOONGARCH_CSR, REG)
> #define KVM_IOC_CPUCFG(REG) LOONGARCH_REG_64(KVM_REG_LOONGARCH_CPUCFG, REG)
>
> +/* Device Control API on vm fd */
> +#define KVM_LOONGARCH_VM_FEAT_CTRL 0
> +#define KVM_LOONGARCH_VM_FEAT_X86BT 0
> +#define KVM_LOONGARCH_VM_FEAT_ARMBT 1
> +#define KVM_LOONGARCH_VM_FEAT_MIPSBT 2
I think LBT should be vcpu features rather than vm features, which is
the same like CPUCFG and FP/SIMD.
Moreover, this patch can be merged to the 2nd one.
Huacai
> +
> /* Device Control API on vcpu fd */
> #define KVM_LOONGARCH_VCPU_CPUCFG 0
> #define KVM_LOONGARCH_VCPU_PVTIME_CTRL 1
> diff --git a/arch/loongarch/kvm/vm.c b/arch/loongarch/kvm/vm.c
> index 6b2e4f66ad26..09e05108c68b 100644
> --- a/arch/loongarch/kvm/vm.c
> +++ b/arch/loongarch/kvm/vm.c
> @@ -99,7 +99,49 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> return r;
> }
>
> +static int kvm_vm_feature_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
> +{
> + switch (attr->attr) {
> + case KVM_LOONGARCH_VM_FEAT_X86BT:
> + if (cpu_has_lbt_x86)
> + return 0;
> + return -ENXIO;
> + case KVM_LOONGARCH_VM_FEAT_ARMBT:
> + if (cpu_has_lbt_arm)
> + return 0;
> + return -ENXIO;
> + case KVM_LOONGARCH_VM_FEAT_MIPSBT:
> + if (cpu_has_lbt_mips)
> + return 0;
> + return -ENXIO;
> + default:
> + return -ENXIO;
> + }
> +}
> +
> +static int kvm_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
> +{
> + switch (attr->group) {
> + case KVM_LOONGARCH_VM_FEAT_CTRL:
> + return kvm_vm_feature_has_attr(kvm, attr);
> + default:
> + return -ENXIO;
> + }
> +}
> +
> int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
> {
> - return -ENOIOCTLCMD;
> + struct kvm *kvm = filp->private_data;
> + void __user *argp = (void __user *)arg;
> + struct kvm_device_attr attr;
> +
> + switch (ioctl) {
> + case KVM_HAS_DEVICE_ATTR:
> + if (copy_from_user(&attr, argp, sizeof(attr)))
> + return -EFAULT;
> +
> + return kvm_vm_has_attr(kvm, &attr);
> + default:
> + return -EINVAL;
> + }
> }
> --
> 2.39.3
>
