Re: [Xen-devel] [PATCH v2 2/3] arm, arm64/xen: move Xen initialization earlier

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Hi Russell,

I am going to queue this up in the xentip tree for 4.2, let me know if
you have any issues.

Cheers,

Stefano

On Tue, 7 Apr 2015, Stefano Stabellini wrote:
> Russell,
> 
> I think that this patch should go via the Xen tree, however as it
> touches arch/arm/kernel/setup.c, I would like your Acked-by before
> adding it to the Xen queue.
> 
> Thanks,
> 
> Stefano
> 
> 
> On Wed, 18 Feb 2015, Julien Grall wrote:
> > From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > 
> > Currently, Xen is initialized/discovered in an initcall. This doesn't
> > allow us to support earlyprintk or choosing the preferred console when
> > running on Xen.
> > 
> > The current function xen_guest_init is now split in 2 parts:
> >     - xen_early_init: Check if there is a Xen node in the device tree
> >     and setup domain type
> >     - xen_guest_init: Retrieve the information from the device node and
> >     initialize Xen (grant table, shared page...)
> > 
> > The former is called in setup_arch, while the latter is an initcall.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> > Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> > Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Cc: Will Deacon <will.deacon@xxxxxxx>
> > 
> > ---
> >     It's based on a patch sent by Stefano nearly 2 years ago [1].
> > 
> >     [1] http://lists.xen.org/archives/html/xen-devel/2013-08/msg02960.html
> > 
> >     Changes in v2:
> >         - Add Ian's ack
> > ---
> >  arch/arm/include/asm/xen/hypervisor.h |  8 +++++
> >  arch/arm/kernel/setup.c               |  2 ++
> >  arch/arm/xen/enlighten.c              | 58 
> > ++++++++++++++++++++---------------
> >  arch/arm64/kernel/setup.c             |  2 ++
> >  4 files changed, 46 insertions(+), 24 deletions(-)
> > 
> > diff --git a/arch/arm/include/asm/xen/hypervisor.h 
> > b/arch/arm/include/asm/xen/hypervisor.h
> > index 1317ee4..04ff8e7 100644
> > --- a/arch/arm/include/asm/xen/hypervisor.h
> > +++ b/arch/arm/include/asm/xen/hypervisor.h
> > @@ -1,6 +1,8 @@
> >  #ifndef _ASM_ARM_XEN_HYPERVISOR_H
> >  #define _ASM_ARM_XEN_HYPERVISOR_H
> >  
> > +#include <linux/init.h>
> > +
> >  extern struct shared_info *HYPERVISOR_shared_info;
> >  extern struct start_info *xen_start_info;
> >  
> > @@ -18,4 +20,10 @@ static inline enum paravirt_lazy_mode 
> > paravirt_get_lazy_mode(void)
> >  
> >  extern struct dma_map_ops *xen_dma_ops;
> >  
> > +#ifdef CONFIG_XEN
> > +void __init xen_early_init(void);
> > +#else
> > +static inline void xen_early_init(void) { return; }
> > +#endif
> > +
> >  #endif /* _ASM_ARM_XEN_HYPERVISOR_H */
> > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> > index e55408e..8b59d0d 100644
> > --- a/arch/arm/kernel/setup.c
> > +++ b/arch/arm/kernel/setup.c
> > @@ -46,6 +46,7 @@
> >  #include <asm/cacheflush.h>
> >  #include <asm/cachetype.h>
> >  #include <asm/tlbflush.h>
> > +#include <asm/xen/hypervisor.h>
> >  
> >  #include <asm/prom.h>
> >  #include <asm/mach/arch.h>
> > @@ -936,6 +937,7 @@ void __init setup_arch(char **cmdline_p)
> >  
> >     arm_dt_init_cpu_maps();
> >     psci_init();
> > +   xen_early_init();
> >  #ifdef CONFIG_SMP
> >     if (is_smp()) {
> >             if (!mdesc->smp_init || !mdesc->smp_init()) {
> > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> > index c8d3a17..1660432 100644
> > --- a/arch/arm/xen/enlighten.c
> > +++ b/arch/arm/xen/enlighten.c
> > @@ -53,6 +53,8 @@ EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
> >  
> >  static __read_mostly unsigned int xen_events_irq;
> >  
> > +static __initdata struct device_node *xen_node;
> > +
> >  /* map fgmfn of domid to lpfn in the current domain */
> >  static int map_foreign_page(unsigned long lpfn, unsigned long fgmfn,
> >                         unsigned int domid)
> > @@ -222,42 +224,28 @@ static irqreturn_t xen_arm_callback(int irq, void 
> > *arg)
> >   * documentation of the Xen Device Tree format.
> >   */
> >  #define GRANT_TABLE_PHYSADDR 0
> > -static int __init xen_guest_init(void)
> > +void __init xen_early_init(void)
> >  {
> > -   struct xen_add_to_physmap xatp;
> > -   static struct shared_info *shared_info_page = 0;
> > -   struct device_node *node;
> >     int len;
> >     const char *s = NULL;
> >     const char *version = NULL;
> >     const char *xen_prefix = "xen,xen-";
> > -   struct resource res;
> > -   phys_addr_t grant_frames;
> >  
> > -   node = of_find_compatible_node(NULL, NULL, "xen,xen");
> > -   if (!node) {
> > +   xen_node = of_find_compatible_node(NULL, NULL, "xen,xen");
> > +   if (!xen_node) {
> >             pr_debug("No Xen support\n");
> > -           return 0;
> > +           return;
> >     }
> > -   s = of_get_property(node, "compatible", &len);
> > +   s = of_get_property(xen_node, "compatible", &len);
> >     if (strlen(xen_prefix) + 3  < len &&
> >                     !strncmp(xen_prefix, s, strlen(xen_prefix)))
> >             version = s + strlen(xen_prefix);
> >     if (version == NULL) {
> >             pr_debug("Xen version not found\n");
> > -           return 0;
> > -   }
> > -   if (of_address_to_resource(node, GRANT_TABLE_PHYSADDR, &res))
> > -           return 0;
> > -   grant_frames = res.start;
> > -   xen_events_irq = irq_of_parse_and_map(node, 0);
> > -   if (!xen_events_irq) {
> > -           pr_debug("Xen event channel interrupt not found\n");
> > -           return -ENODEV;
> > +           return;
> >     }
> >  
> > -   pr_info("Xen %s support found, events_irq=%d gnttab_frame=%pa\n",
> > -                   version, xen_events_irq, &grant_frames);
> > +   pr_info("Xen %s support found\n", version);
> >  
> >     xen_domain_type = XEN_HVM_DOMAIN;
> >  
> > @@ -267,10 +255,32 @@ static int __init xen_guest_init(void)
> >             xen_start_info->flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
> >     else
> >             xen_start_info->flags &= ~(SIF_INITDOMAIN|SIF_PRIVILEGED);
> > +}
> > +
> > +static int __init xen_guest_init(void)
> > +{
> > +   struct xen_add_to_physmap xatp;
> > +   struct shared_info *shared_info_page = NULL;
> > +   struct resource res;
> > +   phys_addr_t grant_frames;
> > +
> > +   if (!xen_domain())
> > +           return 0;
> > +
> > +   if (of_address_to_resource(xen_node, GRANT_TABLE_PHYSADDR, &res)) {
> > +           pr_err("Xen grant table base address not found\n");
> > +           return -ENODEV;
> > +   }
> > +   grant_frames = res.start;
> > +
> > +   xen_events_irq = irq_of_parse_and_map(xen_node, 0);
> > +   if (!xen_events_irq) {
> > +           pr_err("Xen event channel interrupt not found\n");
> > +           return -ENODEV;
> > +   }
> > +
> > +   shared_info_page = (struct shared_info *)get_zeroed_page(GFP_KERNEL);
> >  
> > -   if (!shared_info_page)
> > -           shared_info_page = (struct shared_info *)
> > -                   get_zeroed_page(GFP_KERNEL);
> >     if (!shared_info_page) {
> >             pr_err("not enough memory\n");
> >             return -ENOMEM;
> > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> > index e8420f6..c00ae01 100644
> > --- a/arch/arm64/kernel/setup.c
> > +++ b/arch/arm64/kernel/setup.c
> > @@ -62,6 +62,7 @@
> >  #include <asm/memblock.h>
> >  #include <asm/psci.h>
> >  #include <asm/efi.h>
> > +#include <asm/xen/hypervisor.h>
> >  
> >  unsigned int processor_id;
> >  EXPORT_SYMBOL(processor_id);
> > @@ -388,6 +389,7 @@ void __init setup_arch(char **cmdline_p)
> >     unflatten_device_tree();
> >  
> >     psci_init();
> > +   xen_early_init();
> >  
> >     cpu_read_bootcpu_ops();
> >  #ifdef CONFIG_SMP
> > -- 
> > 2.1.4
> > 
> 

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