On 07.01.2025 11:17, Juergen Gross wrote:
> Add a bitmap with one bit per possible domid indicating the respective
> domain has changed its state (created, deleted, dying, crashed,
> shutdown).
>
> Registering the VIRQ_DOM_EXC event will result in setting the bits for
> all existing domains and resetting all other bits.
>
> As the usage of this bitmap is tightly coupled with the VIRQ_DOM_EXC
> event, it is meant to be used only by a single consumer in the system,
> just like the VIRQ_DOM_EXC event.
>
> Resetting a bit will be done in a future patch.
>
> This information is needed for Xenstore to keep track of all domains.
>
> Signed-off-by: Juergen Gross <jgr...@suse.com>
> ---
> V2:
> - use DOMID_FIRST_RESERVED instead of DOMID_MASK + 1 (Jan Beulich)
> - use const (Jan Beulich)
> - move call of domain_reset_states() into evtchn_bind_virq() (Jan Beulich)
> - dynamically allocate dom_state_changed bitmap (Jan Beulich)
> V3:
> - use xvzalloc_array() (Jan Beulich)
> - don't rename existing label (Jan Beulich)
> V4:
> - add __read_mostly (Jan Beulich)
> - use __set_bit() (Jan Beulich)
This change looks to have been lost, ...
> - fix error handling in evtchn_bind_virq() (Jan Beulich)
> V5:
> - domain_init_states() may be called only if evtchn_bind_virq() has been
> called validly (Jan Beulich)
> V6:
> - guard dom_state_changed bitmap with d->event_lock (Jan Beulich)
... without it being mentioned anywhere, and without it becoming clear why
it would have needed undoing.
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -35,6 +35,7 @@
> #include <xen/irq.h>
> #include <xen/argo.h>
> #include <xen/llc-coloring.h>
> +#include <xen/xvmalloc.h>
> #include <asm/p2m.h>
> #include <asm/processor.h>
> #include <public/sched.h>
> @@ -139,6 +140,51 @@ bool __read_mostly vmtrace_available;
>
> bool __read_mostly vpmu_is_available;
>
> +static unsigned long *__read_mostly dom_state_changed;
> +
> +int domain_init_states(void)
> +{
> + const struct domain *d;
> +
> + ASSERT(!dom_state_changed);
> + ASSERT(rw_is_write_locked(¤t->domain->event_lock));
rw_is_write_locked_by_me()?
> + dom_state_changed = xvzalloc_array(unsigned long,
> + BITS_TO_LONGS(DOMID_FIRST_RESERVED));
> + if ( !dom_state_changed )
> + return -ENOMEM;
> +
> + rcu_read_lock(&domlist_read_lock);
> +
> + for_each_domain ( d )
> + set_bit(d->domain_id, dom_state_changed);
> +
> + rcu_read_unlock(&domlist_read_lock);
> +
> + return 0;
> +}
> +
> +void domain_deinit_states(const struct domain *d)
> +{
> + ASSERT(rw_is_write_locked(&d->event_lock));
Again.
Jan
