On Thu, May 28, 2009 at 12:54:46PM +0300, Gleb Natapov wrote:
> Archs are free to use vcpu_id as they see fit. For x86 it is used as
> vcpu's apic id. New ioctl is added to configure boot vcpu id that was
> assumed to be 0 till now.
>
> Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
> ---
> include/linux/kvm.h | 2 +
> include/linux/kvm_host.h | 2 +
> virt/kvm/kvm_main.c | 50 ++++++++++++++++++++++++++-------------------
> 3 files changed, 33 insertions(+), 21 deletions(-)
>
> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
> index 632a856..d10ab5d 100644
> --- a/include/linux/kvm.h
> +++ b/include/linux/kvm.h
> @@ -430,6 +430,7 @@ struct kvm_trace_rec {
> #ifdef __KVM_HAVE_PIT
> #define KVM_CAP_PIT2 33
> #endif
> +#define KVM_CAP_SET_BOOT_CPU_ID 34
>
> #ifdef KVM_CAP_IRQ_ROUTING
>
> @@ -537,6 +538,7 @@ struct kvm_irqfd {
> #define KVM_DEASSIGN_DEV_IRQ _IOW(KVMIO, 0x75, struct kvm_assigned_irq)
> #define KVM_IRQFD _IOW(KVMIO, 0x76, struct kvm_irqfd)
> #define KVM_CREATE_PIT2 _IOW(KVMIO, 0x77, struct kvm_pit_config)
> +#define KVM_SET_BOOT_CPU_ID _IO(KVMIO, 0x78)
>
> /*
> * ioctls for vcpu fds
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index e9e0cd8..e368a14 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -130,8 +130,10 @@ struct kvm {
> int nmemslots;
> struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS +
> KVM_PRIVATE_MEM_SLOTS];
> + u32 bsp_vcpu_id;
> struct kvm_vcpu *bsp_vcpu;
> struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
> + atomic_t online_vcpus;
> struct list_head vm_list;
> struct kvm_io_bus mmio_bus;
> struct kvm_io_bus pio_bus;
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 5a55fe0..d65c637 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -693,11 +693,6 @@ out:
> }
> #endif
>
> -static inline int valid_vcpu(int n)
> -{
> - return likely(n >= 0 && n < KVM_MAX_VCPUS);
> -}
> -
> inline int kvm_is_mmio_pfn(pfn_t pfn)
> {
> if (pfn_valid(pfn)) {
> @@ -1713,15 +1708,12 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu)
> /*
> * Creates some virtual cpus. Good luck creating more than one.
> */
> -static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
> +static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
> {
> int r;
> struct kvm_vcpu *vcpu;
>
> - if (!valid_vcpu(n))
> - return -EINVAL;
> -
> - vcpu = kvm_arch_vcpu_create(kvm, n);
> + vcpu = kvm_arch_vcpu_create(kvm, id);
> if (IS_ERR(vcpu))
> return PTR_ERR(vcpu);
>
> @@ -1732,25 +1724,36 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
> return r;
>
> mutex_lock(&kvm->lock);
> - if (kvm->vcpus[n]) {
> - r = -EEXIST;
> + if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
> + r = -EINVAL;
> goto vcpu_destroy;
> }
> - kvm->vcpus[n] = vcpu;
> - if (n == 0)
> - kvm->bsp_vcpu = vcpu;
> - mutex_unlock(&kvm->lock);
> +
> + for (r = 0; r < atomic_read(&kvm->online_vcpus); r++)
> + if (kvm->vcpus[r]->vcpu_id == id) {
> + r = -EEXIST;
> + goto vcpu_destroy;
> + }
> +
> + BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
>
> /* Now it's all set up, let userspace reach it */
> kvm_get_kvm(kvm);
> r = create_vcpu_fd(vcpu);
> - if (r < 0)
> - goto unlink;
> + if (r < 0) {
> + kvm_put_kvm(kvm);
> + goto vcpu_destroy;
> + }
> +
> + kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
> + smp_wmb();
> + atomic_inc(&kvm->online_vcpus);
> +
> + if (kvm->bsp_vcpu_id == id)
> + kvm->bsp_vcpu = vcpu;
> + mutex_unlock(&kvm->lock);
> return r;
>
> -unlink:
> - mutex_lock(&kvm->lock);
> - kvm->vcpus[n] = NULL;
> vcpu_destroy:
> mutex_unlock(&kvm->lock);
> kvm_arch_vcpu_destroy(vcpu);
> @@ -2223,6 +2226,10 @@ static long kvm_vm_ioctl(struct file *filp,
> r = kvm_irqfd(kvm, data.fd, data.gsi, data.flags);
> break;
> }
> + case KVM_SET_BOOT_CPU_ID:
> + kvm->bsp_vcpu_id = arg;
> + r = 0;
> + break;
Don't you also need to update the bsp_vcpu pointer? And aren't these two
(bsp_vcpu pointer and bsp_vcpu_id) somewhat redundant?
Other than looks fine.
> default:
> r = kvm_arch_vm_ioctl(filp, ioctl, arg);
> }
> @@ -2289,6 +2296,7 @@ static long kvm_dev_ioctl_check_extension_generic(long arg)
> case KVM_CAP_USER_MEMORY:
> case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
> case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
> + case KVM_CAP_SET_BOOT_CPU_ID:
> return 1;
> #ifdef CONFIG_HAVE_KVM_IRQCHIP
> case KVM_CAP_IRQ_ROUTING:
> --
> 1.6.2.1
>
> --
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