[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH for-4.19???] x86/physdev: replace physdev_{,un}map_pirq() checking against DOMID_SELF
On Wed, 2024-06-12 at 10:44 +0200, Jan Beulich wrote: > It's hardly ever correct to check for just DOMID_SELF, as guests have > ways to figure out their domain IDs and hence could instead use those > as > inputs to respective hypercalls. Note, however, that for ordinary > DomU-s > the adjustment is relaxing things rather than tightening them, since > - as a result of XSA-237 - the respective XSM checks would have > rejected > self (un)mapping attempts for other than the control domain. > > Since in physdev_map_pirq() handling overall is a little easier this > way, move obtaining of the domain pointer into the caller. Doing the > same for physdev_unmap_pirq() is just to keep both consistent in this > regard. For both this has the advantage that it is now provable (by > the > build not failing) that there are no DOMID_SELF checks left (and none > could easily be re-added). > > Fixes: 0b469cd68708 ("Interrupt remapping to PIRQs in HVM guests") > Fixes: 9e1a3415b773 ("x86: fixes after emuirq changes") > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx> ~ Oleksii > --- > Note that the moving of rcu_lock_domain_by_any_id() is also going to > help > https://lists.xen.org/archives/html/xen-devel/2024-06/msg00206.html. > > --- a/xen/arch/x86/physdev.c > +++ b/xen/arch/x86/physdev.c > @@ -18,9 +18,9 @@ > #include <xsm/xsm.h> > #include <asm/p2m.h> > > -int physdev_map_pirq(domid_t domid, int type, int *index, int > *pirq_p, > +int physdev_map_pirq(struct domain *d, int type, int *index, int > *pirq_p, > struct msi_info *msi); > -int physdev_unmap_pirq(domid_t domid, int pirq); > +int physdev_unmap_pirq(struct domain *d, int pirq); > > #include "x86_64/mmconfig.h" > > @@ -88,13 +88,12 @@ static int physdev_hvm_map_pirq( > return ret; > } > > -int physdev_map_pirq(domid_t domid, int type, int *index, int > *pirq_p, > +int physdev_map_pirq(struct domain *d, int type, int *index, int > *pirq_p, > struct msi_info *msi) > { > - struct domain *d = current->domain; > int ret; > > - if ( domid == DOMID_SELF && is_hvm_domain(d) && has_pirq(d) ) > + if ( d == current->domain && is_hvm_domain(d) && has_pirq(d) ) > { > /* > * Only makes sense for vector-based callback, else HVM-IRQ > logic > @@ -106,13 +105,9 @@ int physdev_map_pirq(domid_t domid, int > return physdev_hvm_map_pirq(d, type, index, pirq_p); > } > > - d = rcu_lock_domain_by_any_id(domid); > - if ( d == NULL ) > - return -ESRCH; > - > ret = xsm_map_domain_pirq(XSM_DM_PRIV, d); > if ( ret ) > - goto free_domain; > + return ret; > > /* Verify or get irq. */ > switch ( type ) > @@ -135,24 +130,17 @@ int physdev_map_pirq(domid_t domid, int > break; > } > > - free_domain: > - rcu_unlock_domain(d); > return ret; > } > > -int physdev_unmap_pirq(domid_t domid, int pirq) > +int physdev_unmap_pirq(struct domain *d, int pirq) > { > - struct domain *d; > int ret = 0; > > - d = rcu_lock_domain_by_any_id(domid); > - if ( d == NULL ) > - return -ESRCH; > - > - if ( domid != DOMID_SELF || !is_hvm_domain(d) || !has_pirq(d) ) > + if ( d != current->domain || !is_hvm_domain(d) || !has_pirq(d) ) > ret = xsm_unmap_domain_pirq(XSM_DM_PRIV, d); > if ( ret ) > - goto free_domain; > + return ret; > > if ( is_hvm_domain(d) && has_pirq(d) ) > { > @@ -160,8 +148,8 @@ int physdev_unmap_pirq(domid_t domid, in > if ( domain_pirq_to_emuirq(d, pirq) != IRQ_UNBOUND ) > ret = unmap_domain_pirq_emuirq(d, pirq); > write_unlock(&d->event_lock); > - if ( domid == DOMID_SELF || ret ) > - goto free_domain; > + if ( d == current->domain || ret ) > + return ret; > } > > pcidevs_lock(); > @@ -170,8 +158,6 @@ int physdev_unmap_pirq(domid_t domid, in > write_unlock(&d->event_lock); > pcidevs_unlock(); > > - free_domain: > - rcu_unlock_domain(d); > return ret; > } > #endif /* COMPAT */ > @@ -184,6 +170,8 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_H > > switch ( cmd ) > { > + struct domain *d; > + > case PHYSDEVOP_eoi: { > struct physdev_eoi eoi; > struct pirq *pirq; > @@ -331,8 +319,15 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_H > msi.sbdf.devfn = map.devfn; > msi.entry_nr = map.entry_nr; > msi.table_base = map.table_base; > - ret = physdev_map_pirq(map.domid, map.type, &map.index, > &map.pirq, > - &msi); > + > + d = rcu_lock_domain_by_any_id(map.domid); > + ret = -ESRCH; > + if ( !d ) > + break; > + > + ret = physdev_map_pirq(d, map.type, &map.index, &map.pirq, > &msi); > + > + rcu_unlock_domain(d); > > if ( map.type == MAP_PIRQ_TYPE_MULTI_MSI ) > map.entry_nr = msi.entry_nr; > @@ -348,7 +343,15 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_H > if ( copy_from_guest(&unmap, arg, 1) != 0 ) > break; > > - ret = physdev_unmap_pirq(unmap.domid, unmap.pirq); > + d = rcu_lock_domain_by_any_id(unmap.domid); > + ret = -ESRCH; > + if ( !d ) > + break; > + > + ret = physdev_unmap_pirq(d, unmap.pirq); > + > + rcu_unlock_domain(d); > + > break; > } >
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