Re: [PATCH V3 08/23] xen/ioreq: Move x86's ioreq_server to struct domain

[Oleksandr <olekstysh@xxxxxxxxx>]

On 07.12.20 14:04, Jan Beulich wrote:

Hi Jan

> On 30.11.2020 11:31, Oleksandr Tyshchenko wrote:
> > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> >
> > The IOREQ is a common feature now and this struct will be used
> > on Arm as is. Move it to common struct domain. This also
> > significantly reduces the layering violation in the common code
> > (*arch.hvm* usage).
> >
> > We don't move ioreq_gfn since it is not used in the common code
> > (the "legacy" mechanism is x86 specific).
> >
> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> Applicable parts
> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
Thank you.


> yet with a question, but maybe more to Paul than to you:
>
> > --- a/xen/include/asm-x86/hvm/domain.h
> > +++ b/xen/include/asm-x86/hvm/domain.h
> > @@ -63,8 +63,6 @@ struct hvm_pi_ops {
> >       void (*vcpu_block)(struct vcpu *);
> >   };
> >   
> > -#define MAX_NR_IOREQ_SERVERS 8
> > -
> >   struct hvm_domain {
> >       /* Guest page range used for non-default ioreq servers */
> >       struct {
> > @@ -73,12 +71,6 @@ struct hvm_domain {
> >           unsigned long legacy_mask; /* indexed by HVM param number */
> >       } ioreq_gfn;
> >   
> > -    /* Lock protects all other values in the sub-struct and the default */
> > -    struct {
> > -        spinlock_t              lock;
> > -        struct ioreq_server *server[MAX_NR_IOREQ_SERVERS];
> > -    } ioreq_server;
> > -
> >       /* Cached CF8 for guest PCI config cycles */
> >       uint32_t                pci_cf8;
> >   
> > --- a/xen/include/xen/sched.h
> > +++ b/xen/include/xen/sched.h
> > @@ -316,6 +316,8 @@ struct sched_unit {
> >   
> >   struct evtchn_port_ops;
> >   
> > +#define MAX_NR_IOREQ_SERVERS 8
> > +
> >   struct domain
> >   {
> >       domid_t          domain_id;
> > @@ -523,6 +525,14 @@ struct domain
> >       /* Argo interdomain communication support */
> >       struct argo_domain *argo;
> >   #endif
> > +
> > +#ifdef CONFIG_IOREQ_SERVER
> > +    /* Lock protects all other values in the sub-struct and the default */
> > +    struct {
> > +        spinlock_t              lock;
> > +        struct ioreq_server     *server[MAX_NR_IOREQ_SERVERS];
> > +    } ioreq_server;
> > +#endif
> The comment gets merely moved, but what "default" does it talk about?
> Is this a stale part which would better be dropped at this occasion?
I saw Paul's answer, will drop stale part.


--
Regards,

Oleksandr Tyshchenko