Re: [Xen-devel] [PATCH RFC 2/3] x86/xen/time: setup vcpu 0 time info page

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 12/28/2015 04:52 PM, Joao Martins wrote:
> +
> +static int xen_setup_vsyscall_time_info(int cpu)
> +{
> +       struct pvclock_vsyscall_time_info *ti;
> +       struct vcpu_register_time_memory_area t;
> +       struct pvclock_vcpu_time_info *pvti;
> +       unsigned long mem;
> +       int ret, size;
> +       u8 flags;
> +
> +       ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area,
> +                                cpu, NULL);
> +       if (ret == -ENOSYS) {
> +               pr_debug("xen: vcpu_time_info placement not supported\n");
> +               return -ENOTSUPP;
> +       }
I don't think this is necessary.

> +
> +       size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info));
> +       mem = memblock_alloc(size, PAGE_SIZE);
> +       if (!mem)
> +               return -ENOMEM;
> +
> +       ti = __va(mem);
> +       memset(ti, 0, size);
Can you just use get_zeroed_page()? (struct pvclock_vsyscall_time_info 
is always less than a page, isn't it?).

-boris


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel