[Xen-devel] RE: [PATCH] Add memory hotadd to pvops dom0

["Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>]

Ok, I will CC Len in next sending.
As for "Xen should handle ACPI", yes, this is one argument. But I suspect there 
are a lot of against point to it, like the complex of ACPI, the maintain effort 
of ACPICA, how to share ACPI between xen/dom0 etc, so I'm not sure if this 
argument is strong enough :-)

I will reply in a separated mail to Konrad and send out a update later.

--jyh

>-----Original Message-----
>From: Jeremy Fitzhardinge [mailto:jeremy@xxxxxxxx]
>Sent: Saturday, December 19, 2009 8:07 AM
>To: Jiang, Yunhong
>Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
>Subject: Re: [PATCH] Add memory hotadd to pvops dom0
>
>On 12/18/2009 02:27 AM, Jiang, Yunhong wrote:
>> When memory hotadd event happen, a Xen hook will be called, to notify 
>> hypervisor
>of the new added memory.
>>
>> Because xen hypervisor will use the new memory to setup frametable/m2p table,
>so dom0 will always return success to acpi bios, and notify xen hypervisor 
>later.
>>
>> It add a hook in driver/acpi/acpi_memhotplug.c, but that change is quite 
>> small, not
>sure if it is acceptable. Other method is to provide a xen specific
>acpi_memory_device_driver, but I'm not sure if it worth to add so much 
>changes, to
>simply avoid two line hooks.
>>
>
>Yeah; run it by Len and see if he objects violently or not.
>
>Aside from that, it looks OK, though I agree with all Konrad's comments.
>
>But I have to say it looks more like an argument for "Xen should handle
>ACPI" than against...
>
>     J
>
>> Signed-off-by: Jiang, Yunhong<yunhong.jiang@xxxxxxxxx>
>> ---
>>   drivers/acpi/acpi_memhotplug.c    |    5 +
>>   drivers/xen/Makefile              |    1 +
>>   drivers/xen/xen_acpi_memhotplug.c |  197
>+++++++++++++++++++++++++++++++++++++
>>   include/xen/acpi.h                |    4 +
>>   include/xen/interface/platform.h  |   10 ++
>>   5 files changed, 217 insertions(+), 0 deletions(-)
>>   create mode 100644 drivers/xen/xen_acpi_memhotplug.c
>>
>> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
>> index 50e17c7..75e6b72 100644
>> --- a/drivers/acpi/acpi_memhotplug.c
>> +++ b/drivers/acpi/acpi_memhotplug.c
>> @@ -31,6 +31,8 @@
>>   #include<linux/types.h>
>>   #include<linux/memory_hotplug.h>
>>   #include<acpi/acpi_drivers.h>
>> +#include<acpi/acpi_numa.h>
>> +#include<xen/acpi.h>
>>
>>   #define ACPI_MEMORY_DEVICE_CLASS           "memory"
>>   #define ACPI_MEMORY_DEVICE_HID                     "PNP0C80"
>> @@ -215,6 +217,9 @@ static int acpi_memory_enable_device(struct
>acpi_memory_device *mem_device)
>>              return result;
>>      }
>>
>> +    if (xen_initial_domain())
>> +            return xen_add_memory(mem_device);
>> +
>>      node = acpi_get_node(mem_device->device->handle);
>>      /*
>>       * Tell the VM there is more memory here...
>> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
>> index 6325be1..fbacea7 100644
>> --- a/drivers/xen/Makefile
>> +++ b/drivers/xen/Makefile
>> @@ -19,6 +19,7 @@ obj-$(CONFIG_XEN_SYS_HYPERVISOR)   += sys-hypervisor.o
>>   obj-$(CONFIG_XEN_S3)                       += acpi.o
>>   obj-$(CONFIG_XEN_MCE)                      += mce.o
>>   obj-$(CONFIG_ACPI_PROCESSOR_XEN)   += acpi_processor.o
>> +obj-$(CONFIG_ACPI_HOTPLUG_MEMORY)   += xen_acpi_memhotplug.o
>>
>>   xen-gntdev-y                               := gntdev.o
>>   xen-evtchn-y                               := evtchn.o
>> diff --git a/drivers/xen/xen_acpi_memhotplug.c
>b/drivers/xen/xen_acpi_memhotplug.c
>> new file mode 100644
>> index 0000000..17b936e
>> --- /dev/null
>> +++ b/drivers/xen/xen_acpi_memhotplug.c
>> @@ -0,0 +1,197 @@
>> +#include<linux/kernel.h>
>> +#include<linux/module.h>
>> +#include<linux/init.h>
>> +#include<linux/types.h>
>> +#include<linux/memory_hotplug.h>
>> +#include<acpi/acpi_drivers.h>
>> +#include<xen/interface/platform.h>
>> +#include<linux/interrupt.h>
>> +#include<linux/spinlock.h>
>> +#include<asm/xen/hypervisor.h>
>> +#include<asm/xen/hypercall.h>
>> +#include<xen/acpi.h>
>> +
>> +struct xen_hotmem_entry {
>> +    struct list_head hotmem_list;
>> +    uint64_t start;
>> +    uint64_t end;
>> +    uint32_t flags;
>> +    uint32_t pxm;
>> +};
>> +
>> +struct xen_hotmem_list {
>> +    struct list_head list;
>> +    int entry_nr;
>> +} xen_hotmem;
>> +
>> +DEFINE_SPINLOCK(xen_hotmem_lock);
>> +
>> +static int xen_hyper_addmem(struct xen_hotmem_entry *entry)
>> +{
>> +    int ret;
>> +
>> +    xen_platform_op_t op = {
>> +            .cmd            = XENPF_mem_hotadd,
>> +            .interface_version  = XENPF_INTERFACE_VERSION,
>> +    };
>> +    op.u.mem_add.spfn = entry->start>>  PAGE_SHIFT;
>> +    op.u.mem_add.epfn = entry->end>>  PAGE_SHIFT;
>> +    op.u.mem_add.flags = entry->flags;
>> +    op.u.mem_add.pxm = entry->pxm;
>> +
>> +    ret = HYPERVISOR_dom0_op(&op);
>> +    return ret;
>> +}
>> +static int xen_hotmem_free(struct xen_hotmem_entry *entry)
>> +{
>> +    list_del(&entry->hotmem_list);
>> +    kfree(entry);
>> +
>> +    return 0;
>> +}
>> +
>> +static void xen_hotmem_dpc(struct work_struct *work)
>> +{
>> +    struct list_head *elem, *tmp;
>> +    struct xen_hotmem_entry *entry;
>> +    unsigned long flags;
>> +    int ret;
>> +
>> +    spin_lock_irqsave(&xen_hotmem_lock, flags);
>> +    list_for_each_safe(elem, tmp,&xen_hotmem.list) {
>> +            entry = list_entry(elem, struct xen_hotmem_entry, hotmem_list);
>> +            ret = xen_hyper_addmem(entry);
>> +            if (ret)
>> +                    printk(KERN_WARNING "xen addmem failed with %x\n", ret);
>> +            xen_hotmem_free(entry);
>> +    }
>> +    spin_unlock_irqrestore(&xen_hotmem_lock, flags);
>> +}
>> +
>> +static DECLARE_WORK(xen_hotmem_work, xen_hotmem_dpc);
>> +
>> +static int xen_acpi_get_pxm(acpi_handle h)
>> +{
>> +    unsigned long long pxm;
>> +    acpi_status status;
>> +    acpi_handle handle;
>> +    acpi_handle phandle = h;
>> +
>> +    do {
>> +            handle = phandle;
>> +            status = acpi_evaluate_integer(handle, "_PXM", NULL,&pxm);
>> +            if (ACPI_SUCCESS(status))
>> +                    return pxm;
>> +            status = acpi_get_parent(handle,&phandle);
>> +    } while (ACPI_SUCCESS(status));
>> +    return -1;
>> +}
>> +
>> +static int add_memory_entry(int pxm, uint64_t start,
>> +                    uint64_t length, uint32_t flags)
>> +{
>> +    struct xen_hotmem_entry *entry;
>> +
>> +    if (pxm<  0 || !length)
>> +            return -1;
>> +
>> +    entry = kzalloc(sizeof(struct xen_hotmem_entry), GFP_ATOMIC);
>> +    if (!entry)
>> +            return -1;
>> +
>> +    INIT_LIST_HEAD(&entry->hotmem_list);
>> +    entry->start = start;
>> +    entry->end = start + length;
>> +    entry->flags = flags;
>> +    entry->pxm = pxm;
>> +
>> +    spin_lock(&xen_hotmem_lock);
>> +
>> +    list_add_tail(&entry->hotmem_list,&xen_hotmem.list);
>> +
>> +    spin_unlock(&xen_hotmem_lock);
>> +
>> +    return 0;
>> +}
>> +
>> +int xen_add_memory(struct acpi_memory_device *mem_device)
>> +{
>> +    int pxm, result;
>> +    int num_enabled = 0;
>> +    struct acpi_memory_info *info;
>> +
>> +    if (!mem_device)
>> +            return -EINVAL;
>> +
>> +    pxm = xen_acpi_get_pxm(mem_device->device->handle);
>> +
>> +    if (pxm<  0)
>> +            return -EINVAL;
>> +
>> +    /*
>> +     * Always return success to ACPI driver, and notify hypervisor later
>> +     * because hypervisor will utilize the memory in memory hotadd hypercal
>> +     */
>> +    list_for_each_entry(info,&mem_device->res_list, list) {
>> +            if (info->enabled) { /* just sanity check...*/
>> +                    num_enabled++;
>> +                    continue;
>> +            }
>> +            /*
>> +             * If the memory block size is zero, please ignore it.
>> +             * Don't try to do the following memory hotplug flowchart.
>> +             */
>> +            if (!info->length)
>> +                    continue;
>> +
>> +            result = add_memory_entry(pxm, info->start_addr,
>> +                                    info->length, 0);
>> +            if (result)
>> +                    continue;
>> +            info->enabled = 1;
>> +            num_enabled++;
>> +    }
>> +
>> +    if (!num_enabled)
>> +            return -EINVAL;
>> +
>> +    schedule_work(&xen_hotmem_work);
>> +    return 0;
>> +}
>> +EXPORT_SYMBOL(xen_add_memory);
>> +
>> +static int xen_memadd_init(void)
>> +{
>> +    if (!xen_initial_domain()) {
>> +            printk(KERN_ERR "xen_memadd is only for Xen dom0\n");
>> +            return -1;
>> +    }
>> +
>> +    INIT_LIST_HEAD(&xen_hotmem.list);
>> +    xen_hotmem.entry_nr = 0;
>> +
>> +    return 0;
>> +}
>> +
>> +static void xen_memadd_exit(void)
>> +{
>> +    unsigned long flags;
>> +    struct list_head *elem, *tmp;
>> +    struct xen_hotmem_entry *entry;
>> +
>> +    spin_lock_irqsave(&xen_hotmem_lock, flags);
>> +    if (xen_hotmem.entry_nr) {
>> +            printk(KERN_WARNING "Still %x mem entries not added\n",
>> +              xen_hotmem.entry_nr);
>> +            list_for_each_safe(elem, tmp,&xen_hotmem.list) {
>> +                    entry = list_entry(elem, struct xen_hotmem_entry,
>> +                                    hotmem_list);
>> +                    xen_hotmem_free(entry);
>> +            }
>> +    }
>> +    spin_unlock_irqrestore(&xen_hotmem_lock, flags);
>> +}
>> +
>> +module_init(xen_memadd_init);
>> +module_exit(xen_memadd_exit);
>> +MODULE_LICENSE("GPL");
>> diff --git a/include/xen/acpi.h b/include/xen/acpi.h
>> index 3e7eab4..b15aa3e 100644
>> --- a/include/xen/acpi.h
>> +++ b/include/xen/acpi.h
>> @@ -41,6 +41,10 @@ int acpi_notify_hypervisor_state(u8 sleep_state,
>>   #define HOTPLUG_TYPE_ADD   0
>>   #define HOTPLUG_TYPE_REMOVE        1
>>
>> +#ifdef CONFIG_ACPI_HOTPLUG_MEMORY
>> +int xen_add_memory(struct acpi_memory_device *mem_device);
>> +#endif
>> +
>>   #if defined(CONFIG_ACPI_PROCESSOR_XEN) ||
>defined(CONFIG_ACPI_PROCESSOR_XEN_MODULE)
>>
>>   struct processor_cntl_xen_ops {
>> diff --git a/include/xen/interface/platform.h 
>> b/include/xen/interface/platform.h
>> index bff3a65..17ae622 100644
>> --- a/include/xen/interface/platform.h
>> +++ b/include/xen/interface/platform.h
>> @@ -344,6 +344,15 @@ struct xenpf_cpu_hotadd {
>>      uint32_t pxm;
>>   };
>>
>> +
>> +#define XENPF_mem_hotadd    59
>> +struct xenpf_mem_hotadd {
>> +    uint64_t spfn;
>> +    uint64_t epfn;
>> +    uint32_t pxm;
>> +    uint32_t flags;
>> +};
>> +
>>   struct xen_platform_op {
>>      uint32_t cmd;
>>      uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
>> @@ -362,6 +371,7 @@ struct xen_platform_op {
>>              struct xenpf_pcpuinfo          pcpu_info;
>>              struct xenpf_cpu_ol            cpu_ol;
>>              struct xenpf_cpu_hotadd        cpu_add;
>> +            struct xenpf_mem_hotadd        mem_add;
>>              uint8_t                        pad[128];
>>      } u;
>>   };
>>


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