| Message ID | 20181221162650.11515-5-julien.grall@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | xen/arm: Add xentrace support | expand |
On 21.12.18 18:26, Julien Grall wrote: > DOMID_XEN is used to share pages beloging to the hypervisor > (e.g trace buffers). Unlike other domains, DOMID_XEN is a non-auto > translated domain and therefore does not have a P2M. > > This patch adds a special case for DOMID_XEN in get_page_from_gfn. We > may want to provide "non-auto translated helpers" in the future if we > see more case. > > Signed-off-by: Julien Grall <julien.grall@arm.com> Andrii Anisov <andrii_anisov@epam.com>
Hi Andrii, On 21/12/2018 17:26, Andrii Anisov wrote: > > > On 21.12.18 18:26, Julien Grall wrote: >> DOMID_XEN is used to share pages beloging to the hypervisor >> (e.g trace buffers). Unlike other domains, DOMID_XEN is a non-auto >> translated domain and therefore does not have a P2M. >> >> This patch adds a special case for DOMID_XEN in get_page_from_gfn. We >> may want to provide "non-auto translated helpers" in the future if we >> see more case. >> >> Signed-off-by: Julien Grall <julien.grall@arm.com> > > Andrii Anisov <andrii_anisov@epam.com> Is it a wildcard tag? :) Cheers,
On 21.12.18 19:27, Julien Grall wrote: > Is it a wildcard tag? :) No, just a wrong copy-paste. Must be: Reviewed-by: Andrii Anisov <andrii_anisov@epam.com> ;)
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h index a03a033a05..041dea827c 100644 --- a/xen/include/asm-arm/p2m.h +++ b/xen/include/asm-arm/p2m.h @@ -300,7 +300,38 @@ struct page_info *p2m_get_page_from_gfn(struct domain *d, gfn_t gfn, static inline struct page_info *get_page_from_gfn( struct domain *d, unsigned long gfn, p2m_type_t *t, p2m_query_t q) { - return p2m_get_page_from_gfn(d, _gfn(gfn), t); + mfn_t mfn; + p2m_type_t _t; + struct page_info *page; + + /* + * Special case for DOMID_XEN as it is the only domain so far that is + * not auto-translated. + */ + if ( likely(d != dom_xen) ) + return p2m_get_page_from_gfn(d, _gfn(gfn), t); + + if ( !t ) + t = &_t; + + *t = p2m_invalid; + + /* + * DOMID_XEN sees 1-1 RAM. The p2m_type is based on the type of the + * page. + */ + mfn = _mfn(gfn); + page = mfn_to_page(mfn); + + if ( !mfn_valid(mfn) || !get_page(page, d) ) + return NULL; + + if ( page->u.inuse.type_info & PGT_writable_page ) + *t = p2m_ram_rw; + else + *t = p2m_ram_ro; + + return page; } int get_page_type(struct page_info *page, unsigned long type);
DOMID_XEN is used to share pages beloging to the hypervisor (e.g trace buffers). Unlike other domains, DOMID_XEN is a non-auto translated domain and therefore does not have a P2M. This patch adds a special case for DOMID_XEN in get_page_from_gfn. We may want to provide "non-auto translated helpers" in the future if we see more case. Signed-off-by: Julien Grall <julien.grall@arm.com> --- Changes in v3: - Split from "xen/arm: Add support for read-only foreign mappings" - Use likely rather than unlikely - Fix typoes --- xen/include/asm-arm/p2m.h | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)