Re: [RFC PATCH v2] xen/arm: Add support for GICv3 for domU

[Julien Grall <julien.grall@linaro.org>]

Hi,

On 10/29/2014 04:13 PM, Stefano Stabellini wrote:
> FYI we talked f2f about this and we reached the conclusion that we
> should rework this patch to be non-intrusive and acceptable for 4.5.
> After all without it we cannot boot guests on GICv3 systems.

I'm gonna rework this patch (as long as my patch for the DOMCTL) and
send a new version by the end of the week.

Vijay: I will, of course, keep your signed-off-by and author.

Cheers,

> On Tue, 28 Oct 2014, Julien Grall wrote:
>> Hi Stefano,
>>
>> On 28/10/2014 18:12, Stefano Stabellini wrote:
>>> I have just realized that this patch didn't make RC1 last Friday.
>>
>> I asked for few changes: documentation, way to implement the check... but
>> Vijay never came back with a new version.
>>
>>> What should we do about it?
>>>
>>> Without it, I am not sure we should really claim that Xen 4.5 has GICv3
>>> support, given that we wouldn't be able to start any guests on a GICv3
>>> platform.
>>>
>>> I don't think is so risky it couldn't make RC2, but that's not entirely
>>> up to me.
>>
>> This patch series requires to defer the VGIC initialization later.
>>
>> The patch [1] to implement this feature has been deferred to Xen 4.6 because
>> it was only necessary to my non-pci passthrough series (which has not reached
>> Xen 4.5 for various reasons).
>>
>> I don't think this patch should go in Xen 4.5 at this stage of the release
>> (RC1 went out last week), because it modify too much the way to initialize the
>> domain (VGIC has been deferred). Furthermore it has been reworked in a private
>> branch [2] to address the comments.
>>
>> By side effect, the toolstack part for the GICv3 would have to be defer.
>>
>> Regards,
>>
>> [1] https://patches.linaro.org/34664/
>> [2]
>> http://xenbits.xen.org/gitweb/?p=people/julieng/xen-unstable.git;a=commitdiff;h=002b216707ae90b669ffebf009042d5e42b26dc0;hp=30e15fa1f52aa790bf13b5f40dc62d832443846c
>>
>>> On Wed, 8 Oct 2014, Julien Grall wrote:
>>>> Hello Vijay,
>>>>
>>>> On 10/06/2014 01:46 PM, vijay.kilari@gmail.com wrote:
>>>>> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
>>>>> index 7d9eec2..8f3f074 100644
>>>>> --- a/tools/libxl/libxl_types.idl
>>>>> +++ b/tools/libxl/libxl_types.idl
>>>>> @@ -349,6 +349,7 @@ libxl_domain_build_info =
>>>>> Struct("domain_build_info",[
>>>>>       ("disable_migrate", libxl_defbool),
>>>>>       ("cpuid",           libxl_cpuid_policy_list),
>>>>>       ("blkdev_start",    string),
>>>>> +    ("gic_version",     uint32),
>>>>
>>>> How would you differentiate GICv2 from GICv2m with an integer? I think
>>>> an enum would be better to describe the GIC version.
>>>>
>>>>> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
>>>>> index 2ec17ca..5fcb396 100644
>>>>> --- a/tools/libxl/xl_cmdimpl.c
>>>>> +++ b/tools/libxl/xl_cmdimpl.c
>>>>> @@ -1523,6 +1523,9 @@ skip_vfb:
>>>>>       if (!xlu_cfg_get_long (config, "pci_seize", &l, 0))
>>>>>           pci_seize = l;
>>>>>
>>>>> +    if (!xlu_cfg_get_long (config, "gic_version", &l, 0))
>>>>> +        b_info->gic_version = l;
>>>>> +
>>>>
>>>> You have to document this new option in docs/man/xl.cfg.pod.5
>>>>
>>>> [..]
>>>>
>>>>> diff --git a/xen/arch/arm/domctl.c b/xen/arch/arm/domctl.c
>>>>> index 370dd99..1bea026 100644
>>>>> --- a/xen/arch/arm/domctl.c
>>>>> +++ b/xen/arch/arm/domctl.c
>>>>> @@ -10,6 +10,8 @@
>>>>>   #include <xen/errno.h>
>>>>>   #include <xen/sched.h>
>>>>>   #include <xen/hypercall.h>
>>>>> +#include <asm/gic.h>
>>>>> +#include <xen/guest_access.h>
>>>>>   #include <public/domctl.h>
>>>>>
>>>>>   long arch_do_domctl(struct xen_domctl *domctl, struct domain *d,
>>>>> @@ -39,9 +41,36 @@ long arch_do_domctl(struct xen_domctl *domctl, struct
>>>>> domain *d,
>>>>>           if ( domctl->u.configuredomain.nr_spis > (gic_number_lines() -
>>>>> 32) )
>>>>>               return -EINVAL;
>>>>>
>>>>> -        return domain_configure_vgic(d,
>>>>> domctl->u.configuredomain.nr_spis);
>>>>> -    }
>>>>> +        if ( domain_configure_vgic(d,
>>>>> domctl->u.configuredomain.nr_spis) )
>>>>> +            return -EINVAL;
>>>>
>>>> domain_configure_vgic should be called after we check that current
>>>> version of GIC match. The user may want to chose to emulate a GICv2 on
>>>> GICv3 hardware.
>>>>
>>>>> diff --git a/xen/include/public/arch-arm.h
>>>>> b/xen/include/public/arch-arm.h
>>>>> index cebb349..6f80c99 100644
>>>>> --- a/xen/include/public/arch-arm.h
>>>>> +++ b/xen/include/public/arch-arm.h
>>>>> @@ -363,6 +363,14 @@ typedef uint64_t xen_callback_t;
>>>>>    * should instead use the FDT.
>>>>>    */
>>>>>
>>>>> +/* GICv3 address space */
>>>>> +#define GUEST_GICV3_GICD_BASE      0x03001000ULL
>>>>> +#define GUEST_GICV3_GICD_SIZE      0x10000ULL
>>>>> +#define GUEST_GICV3_GICR_BASE      0x03020000ULL
>>>>> +#define GUEST_GICV3_GICR_SIZE      0x200000ULL
>>>>> +#define GUEST_GICV3_RDIST_STRIDE   0x20000ULL
>>>>> +#define GUEST_GICV3_RDIST_REGIONS  0x1ULL
>>>>> +
>>>>
>>>> This should go after "/* Physical Address Space */
>>>>
>>>>>   /* Physical Address Space */
>>>>>   #define GUEST_GICD_BASE   0x03001000ULL
>>>>>   #define GUEST_GICD_SIZE   0x00001000ULL
>>>>
>>>> Please modify those defines, along *GICC* to add GICV2 in the name.
>>>>
>>>>> diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
>>>>> index 8adb8e2..502cfb6 100644
>>>>> --- a/xen/include/public/domctl.h
>>>>> +++ b/xen/include/public/domctl.h
>>>>> @@ -73,6 +73,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_createdomain_t);
>>>>>   struct xen_domctl_configuredomain {
>>>>>       /* IN parameters */
>>>>>       uint32_t nr_spis;
>>>>> +    /* IN/OUT parameter */
>>>>> +    uint32_t gic_version;
>>>>
>>>> uint32_t sounds a bit too much for the gic_version. Maybe a uint8_t?
>>>> Also a better name would be vgic_version.
>>>>
>>>> Futhermore, people reading the structure don't know what value should be
>>>> expected in this field. I would introduce define to specify the
>>>> different value.
>>>>
>>>> Regards,
>>>>
>>>> --
>>>> Julien Grall
>>>>
>>
>> -- 
>> Julien Grall
>>


-- 
Julien Grall