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

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

I have just realized that this patch didn't make RC1 last Friday.

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.


On Wed, 8 Oct 2014, Julien Grall wrote:
> Hello Vijay,
> 
> On 10/06/2014 01:46 PM, vijay.kilari@xxxxxxxxx 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
> 

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