| Message ID | 1458161499-15313-5-git-send-email-ben.sanda@dornerworks.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hello Benjamin, Thank you for the patch. On 16/03/16 20:51, Benjamin Sanda wrote: > From: bensanda <ben.sanda@dornerworks.com> > > Modified xenmem_add_to_physmap_one() to provide support for xentrace on the ARM platform. Checks for DOMID_XEN added via new function, get_pg_owner, ported from x86 code base. This provides correct calls to rcu_lock_domain() when DOMID_XEN is requested. DOMID_XEN checks also adde to skip page to MFN translation (xentrace sends a MFN dirrectly and so does not need to be translated). A line in the commit message should not be longer than 72 characters. > > Signed-off-by: Benjamin Sanda <ben.sanda@dornerworks.com> > --- > xen/arch/arm/mm.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 54 insertions(+), 2 deletions(-) > > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c > index 81f9e2e..b1d834f 100644 > --- a/xen/arch/arm/mm.c > +++ b/xen/arch/arm/mm.c > @@ -41,6 +41,7 @@ > #include <xen/pfn.h> > > struct domain *dom_xen, *dom_io, *dom_cow; > +static struct domain *get_pg_owner(domid_t domid); I would rather avoid to forward declare a function if there is no strict dependency on other functions. Instead, I would add the function before the caller. > > /* Static start-of-day pagetables that we use before the allocators > * are up. These are used by all CPUs during bringup before switching > @@ -1099,7 +1100,8 @@ int xenmem_add_to_physmap_one( > { > struct domain *od; > p2m_type_t p2mt; > - od = rcu_lock_domain_by_any_id(foreign_domid); > + od = get_pg_owner(foreign_domid); > + > if ( od == NULL ) > return -ESRCH; > > @@ -1132,7 +1134,17 @@ int xenmem_add_to_physmap_one( > return -EINVAL; > } > > - mfn = page_to_mfn(page); > + /* If DOMID_XEN then no page to MFN translation is > + needed as we already have the MFN directly */ > + if(DOMID_XEN !=od->domain_id) > + { > + mfn = page_to_mfn(page); > + } > + else > + { > + mfn = idx; > + } > + Please avoid to spread the DOMID_ID specific case everywhere. The cost to calculate the MFN of a page is very limited. > t = p2m_map_foreign; > > rcu_unlock_domain(od); > @@ -1312,6 +1324,46 @@ void clear_and_clean_page(struct page_info *page) > unmap_domain_page(p); > } > > +/* Ported from x86 architecture: checks for special domain requests for > +DOMID_XEN or DOMID_IO which must be handled differently then guest domain > +requests */ > +static struct domain *get_pg_owner(domid_t domid) This function is very similar to the x86 one. I think it would benefit to implement get_pg_owner in the common code and add arch specific helper when it's necessary. Also, please introduce the helper put_pg_owner to stay consistent. > +{ > + struct domain *pg_owner = NULL, *curr = current->domain; > + > + if ( likely(domid == DOMID_SELF) ) > + { > + pg_owner = rcu_lock_current_domain(); > + goto out; > + } > + > + if ( unlikely(domid == curr->domain_id) ) > + { > + goto out; > + } > + > + /* check for special domain cases of DOMID_IO or DOMID_XEN which > + must use rcu_lock_domain() and dom_xen/dom_io as the domid_t */ > + switch ( domid ) > + { > + case DOMID_IO: > + pg_owner = rcu_lock_domain(dom_io); > + break; > + case DOMID_XEN: > + pg_owner = rcu_lock_domain(dom_xen); > + break; > + default: > + if ( (pg_owner = rcu_lock_domain_by_id(domid)) == NULL ) > + { > + break; > + } > + break; > + } > + > + out: > + return pg_owner; > +} > + > /* > * Local variables: > * mode: C > Regards,
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index 81f9e2e..b1d834f 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -41,6 +41,7 @@ #include <xen/pfn.h> struct domain *dom_xen, *dom_io, *dom_cow; +static struct domain *get_pg_owner(domid_t domid); /* Static start-of-day pagetables that we use before the allocators * are up. These are used by all CPUs during bringup before switching @@ -1099,7 +1100,8 @@ int xenmem_add_to_physmap_one( { struct domain *od; p2m_type_t p2mt; - od = rcu_lock_domain_by_any_id(foreign_domid); + od = get_pg_owner(foreign_domid); + if ( od == NULL ) return -ESRCH; @@ -1132,7 +1134,17 @@ int xenmem_add_to_physmap_one( return -EINVAL; } - mfn = page_to_mfn(page); + /* If DOMID_XEN then no page to MFN translation is + needed as we already have the MFN directly */ + if(DOMID_XEN !=od->domain_id) + { + mfn = page_to_mfn(page); + } + else + { + mfn = idx; + } + t = p2m_map_foreign; rcu_unlock_domain(od); @@ -1312,6 +1324,46 @@ void clear_and_clean_page(struct page_info *page) unmap_domain_page(p); } +/* Ported from x86 architecture: checks for special domain requests for +DOMID_XEN or DOMID_IO which must be handled differently then guest domain +requests */ +static struct domain *get_pg_owner(domid_t domid) +{ + struct domain *pg_owner = NULL, *curr = current->domain; + + if ( likely(domid == DOMID_SELF) ) + { + pg_owner = rcu_lock_current_domain(); + goto out; + } + + if ( unlikely(domid == curr->domain_id) ) + { + goto out; + } + + /* check for special domain cases of DOMID_IO or DOMID_XEN which + must use rcu_lock_domain() and dom_xen/dom_io as the domid_t */ + switch ( domid ) + { + case DOMID_IO: + pg_owner = rcu_lock_domain(dom_io); + break; + case DOMID_XEN: + pg_owner = rcu_lock_domain(dom_xen); + break; + default: + if ( (pg_owner = rcu_lock_domain_by_id(domid)) == NULL ) + { + break; + } + break; + } + + out: + return pg_owner; +} + /* * Local variables: * mode: C