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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC 09/15] xen/arm: refactor construct_dom0
On Thu, 14 Jun 2018, Julien Grall wrote:
> Hi Stefano,
>
> On 13/06/18 23:15, Stefano Stabellini wrote:
> > Move generic initializations out of construct_dom0 so that they can be
> > reused.
> >
> > No functional changes in this patch.
> >
> > Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
> > ---
> > xen/arch/arm/domain_build.c | 124
> > ++++++++++++++++++++++++--------------------
> > 1 file changed, 67 insertions(+), 57 deletions(-)
> >
> > diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> > index 4e4cd19..b31c563 100644
> > --- a/xen/arch/arm/domain_build.c
> > +++ b/xen/arch/arm/domain_build.c
> > @@ -2092,73 +2092,27 @@ static void __init find_gnttab_region(struct domain
> > *d,
> > kinfo->gnttab_start, kinfo->gnttab_start + kinfo->gnttab_size);
> > }
> > -int __init construct_dom0(struct domain *d)
> > +int __init __construct_domain(struct domain *d, struct kernel_info *kinfo)
> > {
> > - struct kernel_info kinfo = {};
> > struct vcpu *saved_current;
> > - int rc, i, cpu;
> > + int i, cpu;
> > struct vcpu *v = d->vcpu[0];
> > struct cpu_user_regs *regs = &v->arch.cpu_info->guest_cpu_user_regs;
> > - /* Sanity! */
> > - BUG_ON(d->domain_id != 0);
> > - BUG_ON(d->vcpu[0] == NULL);
> > - BUG_ON(v->is_initialised);
>
> I think we want to keep the last two BUG_ON here. "d->vcpu[0] == NULL" is
> making sure that the value used when setting current is sane.
>
> "v->is_initalised" is making sure this function is not called twice by
> mistake. Indeed the variable will be set at the end of __construct_domain.
OK, I'll make the change.
> > -
> > - printk("*** LOADING DOMAIN 0 ***\n");
> > - if ( dom0_mem <= 0 )
> > - {
> > - warning_add("PLEASE SPECIFY dom0_mem PARAMETER - USING 512M FOR
> > NOW\n");
> > - dom0_mem = MB(512);
> > - }
> > -
> > -
> > - iommu_hwdom_init(d);
> > -
> > - d->max_pages = ~0U;
> > -
> > - kinfo.unassigned_mem = dom0_mem;
> > - kinfo.d = d;
> > -
> > - rc = kernel_probe(&kinfo);
> > - if ( rc < 0 )
> > - return rc;
> > -
> > #ifdef CONFIG_ARM_64
> > /* if aarch32 mode is not supported at EL1 do not allow 32-bit domain
> > */
> > - if ( !(cpu_has_el1_32) && kinfo.type == DOMAIN_32BIT )
> > + if ( !(cpu_has_el1_32) && kinfo->type == DOMAIN_32BIT )
> > {
> > printk("Platform does not support 32-bit domain\n");
> > return -EINVAL;
> > }
> > - d->arch.type = kinfo.type;
>
> Any reason to move this out?
Yeah, initially I left it there but it didn't work. It needs to be set
before calling allocate_memory() for domUs otherwise memory allocations
fail.
> > if ( is_64bit_domain(d) )
> > vcpu_switch_to_aarch64_mode(v);
> > #endif
> > - allocate_memory(d, &kinfo);
>
> I think this could stay here.
Same as before, if I leave it, it doesn't work. allocate_memory() needs
be called before prepare_dtb_domU.
> > - find_gnttab_region(d, &kinfo);
> > -
> > - /* Map extra GIC MMIO, irqs and other hw stuffs to dom0. */
> > - rc = gic_map_hwdom_extra_mappings(d);
> > - if ( rc < 0 )
> > - return rc;
> > -
> > - rc = platform_specific_mapping(d);
> > - if ( rc < 0 )
> > - return rc;
> > -
> > - if ( acpi_disabled )
> > - rc = prepare_dtb(d, &kinfo);
> > - else
> > - rc = prepare_acpi(d, &kinfo);
>
> I think this is probably a call to add "hwdom" in the name of the 2 functions.
I'll do the rename in a later patch (and I'll use hwdom instead of dom0).
> > -
> > - if ( rc < 0 )
> > - return rc;
> > -
> > /*
> > * The following loads use the domain's p2m and require current to
> > * be a vcpu of the domain, temporarily switch
> > @@ -2171,20 +2125,18 @@ int __init construct_dom0(struct domain *d)
> > * kernel_load will determine the placement of the kernel as well
> > * as the initrd & fdt in RAM, so call it first.
> > */
> > - kernel_load(&kinfo);
> > + kernel_load(kinfo);
> > /* initrd_load will fix up the fdt, so call it before dtb_load */
> > - initrd_load(&kinfo);
> > - dtb_load(&kinfo);
> > + initrd_load(kinfo);
> > + dtb_load(kinfo);
> > /* Now that we are done restore the original p2m and current. */
> > set_current(saved_current);
> > p2m_restore_state(saved_current);
> > - discard_initial_modules();
> > -
> > memset(regs, 0, sizeof(*regs));
> > - regs->pc = (register_t)kinfo.entry;
> > + regs->pc = (register_t)kinfo->entry;
> > if ( is_32bit_domain(d) )
> > {
> > @@ -2202,14 +2154,14 @@ int __init construct_dom0(struct domain *d)
> > */
> > regs->r0 = 0; /* SBZ */
> > regs->r1 = 0xffffffff; /* We use DTB therefore no machine id */
> > - regs->r2 = kinfo.dtb_paddr;
> > + regs->r2 = kinfo->dtb_paddr;
> > }
> > #ifdef CONFIG_ARM_64
> > else
> > {
> > regs->cpsr = PSR_GUEST64_INIT;
> > /* From linux/Documentation/arm64/booting.txt */
> > - regs->x0 = kinfo.dtb_paddr;
> > + regs->x0 = kinfo->dtb_paddr;
> > regs->x1 = 0; /* Reserved for future use */
> > regs->x2 = 0; /* Reserved for future use */
> > regs->x3 = 0; /* Reserved for future use */
> > @@ -2235,6 +2187,64 @@ int __init construct_dom0(struct domain *d)
> > return 0;
> > }
> > +int __init construct_dom0(struct domain *d)
> > +{
> > + struct kernel_info kinfo = {};
> > + int rc;
> > +
> > + struct vcpu *v = d->vcpu[0];
> > +
> > + /* Sanity! */
> > + BUG_ON(d->domain_id != 0);
> > + BUG_ON(d->vcpu[0] == NULL);
> > + BUG_ON(v->is_initialised);
> > +
> > + printk("*** LOADING DOMAIN 0 ***\n");
> > + if ( dom0_mem <= 0 )
> > + {
> > + warning_add("PLEASE SPECIFY dom0_mem PARAMETER - USING 512M FOR
> > NOW\n");
> > + dom0_mem = MB(512);
> > + }
> > +
> > +
>
> No need to copy the second newline :).
:-)
> > + iommu_hwdom_init(d);
> > +
> > + d->max_pages = ~0U;
> > +
> > + kinfo.unassigned_mem = dom0_mem;
> > + kinfo.d = d;
> > +
> > + rc = kernel_probe(&kinfo);
> > + if ( rc < 0 )
> > + return rc;
> > +
> > + allocate_memory(d, &kinfo);
> > + find_gnttab_region(d, &kinfo);
> > +
> > + /* Map extra GIC MMIO, irqs and other hw stuffs to dom0. */
> > + rc = gic_map_hwdom_extra_mappings(d);
> > + if ( rc < 0 )
> > + return rc;
> > +
> > + rc = platform_specific_mapping(d);
> > + if ( rc < 0 )
> > + return rc;
> > +
> > + d->arch.type = kinfo.type;
> > +
> > + if ( acpi_disabled )
> > + rc = prepare_dtb(d, &kinfo);
> > + else
> > + rc = prepare_acpi(d, &kinfo);
> > +
> > + if ( rc < 0 )
> > + return rc;
> > +
> > + discard_initial_modules();
>
> You say "no functional change" in this patch. But this is one. The module are
> now discard much earlier. This imply that memory baking the Image/Initrd will
> be free to be re-used at any time.
>
> I don't think this is what we want. Unless you can promise no memory is
> allocated in __construct_domain().
discard_initial_modules() will be moved later by patch #14, but I think
it makes sense to call discard_initial_modules() after
__construct_domain() here.
> > +
> > + return __construct_domain(d, &kinfo);
> > +}
> > +
> > /*
> > * Local variables:
> > * mode: C
> >
>
> Cheers,
>
> --
> Julien Grall
>
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