| Message ID | 1438966019-19322-5-git-send-email-julien.grall@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 7 Aug 2015, Julien Grall wrote: > Currently, a grant is always based on the Xen page granularity (i.e > 4KB). When Linux is using a different page granularity, a single page > will be split between multiple grants. > > The new helpers will be in charge to split the Linux page into grants and ^ of splitting > call a function given by the caller on each grant. > > Also provide an helper to count the number of grants within a given > contiguous region. > > Note that the x86/include/asm/xen/page.h is now including > xen/interface/grant_table.h rather than xen/grant_table.h. It's > necessary because xen/grant_table.h depends on asm/xen/page.h and will > break the compilation. Furthermore, only definition in > interface/grant_table.h was required. ^ is > Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > --- > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> > Cc: David Vrabel <david.vrabel@citrix.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: x86@kernel.org > > Changes in v3: > - Fix error reported by checkpatch.pl > - Typoes > - s/pfn/xen_pfn/ in gnttab_foreach_grant > - Drop the possibility to use less data. The complexity is moved > in netback which is the only user > - Rename gnttab_foreach_grant into gnttab_foreach_grant_in_range > - s/offset/start/ in gnttab_count_grant and update the > description of the parameter > - s/mfn/gfn base on the new terminologies > - Add EXPORT_SYMBOL_GPL for gnttab_foreach_grant_in_range > - Use xen_offset_in_page and XEN_PFN_DOWN whenever it's possible > - Fix compilation on x86. > > Changes in v2: > - Patch added > --- > arch/x86/include/asm/xen/page.h | 2 +- > drivers/xen/grant-table.c | 26 +++++++++++++++++++++++++ > include/xen/grant_table.h | 42 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 69 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h > index 0b762f6..501479e 100644 > --- a/arch/x86/include/asm/xen/page.h > +++ b/arch/x86/include/asm/xen/page.h > @@ -12,7 +12,7 @@ > #include <asm/pgtable.h> > > #include <xen/interface/xen.h> > -#include <xen/grant_table.h> > +#include <xen/interface/grant_table.h> > #include <xen/features.h> > > /* Xen machine address */ > diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c > index 62f591f..94ae0fd 100644 > --- a/drivers/xen/grant-table.c > +++ b/drivers/xen/grant-table.c > @@ -776,6 +776,32 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count) > } > EXPORT_SYMBOL_GPL(gnttab_batch_copy); > > +void gnttab_foreach_grant_in_range(struct page *page, > + unsigned int offset, > + unsigned int len, > + xen_grant_fn_t fn, > + void *data) > +{ > + unsigned int goffset; > + unsigned int glen; > + unsigned long xen_pfn; > + > + len = min_t(unsigned int, PAGE_SIZE - offset, len); > + goffset = xen_offset_in_page(offset); > + > + xen_pfn = xen_page_to_pfn(page) + XEN_PFN_DOWN(offset); > + > + while (len) { > + glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len); > + fn(pfn_to_gfn(xen_pfn), goffset, glen, data); > + > + goffset = 0; > + xen_pfn++; > + len -= glen; > + } > +} > +EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range); > + > int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, > struct gnttab_map_grant_ref *kmap_ops, > struct page **pages, unsigned int count) > diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h > index 4478f4b..2a8ebe8 100644 > --- a/include/xen/grant_table.h > +++ b/include/xen/grant_table.h > @@ -45,8 +45,10 @@ > #include <asm/xen/hypervisor.h> > > #include <xen/features.h> > +#include <xen/page.h> > #include <linux/mm_types.h> > #include <linux/page-flags.h> > +#include <linux/kernel.h> > > #define GNTTAB_RESERVED_XENSTORE 1 > > @@ -224,4 +226,44 @@ static inline struct xen_page_foreign *xen_page_foreign(struct page *page) > #endif > } > > +/* Split Linux page in chunk of the size of the grant and call fn > + * > + * Parameters of fn: > + * gfn: guest frame number > + * offset: offset in the grant > + * len: length of the data in the grant. > + * data: internal information > + */ > +typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset, > + unsigned int len, void *data); > + > +void gnttab_foreach_grant_in_range(struct page *page, > + unsigned int offset, > + unsigned int len, > + xen_grant_fn_t fn, > + void *data); > + > +/* Helper to get to call fn only on the first "grant chunk" */ > +static inline void gnttab_one_grant(struct page *page, unsigned int offset, > + unsigned len, xen_grant_fn_t fn, > + void *data) > +{ > + /* The first request is limited to the size of one grant */ > + len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK), > + len); > + > + gnttab_foreach_grant_in_range(page, offset, len, fn, data); > +} > + > +/* Get the number of grant in a specified region > + * > + * start: Offset from the beginning of the first page > + * len: total length of data (can cross multiple page) > + */ > +static inline unsigned int gnttab_count_grant(unsigned int start, > + unsigned int len) > +{ > + return XEN_PFN_UP(xen_offset_in_page(start) + len); > +} > + > #endif /* __ASM_GNTTAB_H__ */ > -- > 2.1.4 >
On 07/08/15 17:46, Julien Grall wrote: > Currently, a grant is always based on the Xen page granularity (i.e > 4KB). When Linux is using a different page granularity, a single page > will be split between multiple grants. > > The new helpers will be in charge to split the Linux page into grants and > call a function given by the caller on each grant. > > Also provide an helper to count the number of grants within a given > contiguous region. > > Note that the x86/include/asm/xen/page.h is now including > xen/interface/grant_table.h rather than xen/grant_table.h. It's > necessary because xen/grant_table.h depends on asm/xen/page.h and will > break the compilation. Furthermore, only definition in > interface/grant_table.h was required. Reviewed-by: David Vrabel <david.vrabel@citrix.com> But... > +/* Helper to get to call fn only on the first "grant chunk" */ > +static inline void gnttab_one_grant(struct page *page, unsigned int offset, > + unsigned len, xen_grant_fn_t fn, > + void *data) ...call this gnttab_for_one_grant(). David
Hi David, On 20/08/15 10:51, David Vrabel wrote: > On 07/08/15 17:46, Julien Grall wrote: >> Currently, a grant is always based on the Xen page granularity (i.e >> 4KB). When Linux is using a different page granularity, a single page >> will be split between multiple grants. >> >> The new helpers will be in charge to split the Linux page into grants and >> call a function given by the caller on each grant. >> >> Also provide an helper to count the number of grants within a given >> contiguous region. >> >> Note that the x86/include/asm/xen/page.h is now including >> xen/interface/grant_table.h rather than xen/grant_table.h. It's >> necessary because xen/grant_table.h depends on asm/xen/page.h and will >> break the compilation. Furthermore, only definition in >> interface/grant_table.h was required. > > Reviewed-by: David Vrabel <david.vrabel@citrix.com> > But... > >> +/* Helper to get to call fn only on the first "grant chunk" */ >> +static inline void gnttab_one_grant(struct page *page, unsigned int offset, >> + unsigned len, xen_grant_fn_t fn, >> + void *data) > > ...call this gnttab_for_one_grant(). Will rename it on the next version. Regards,
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 0b762f6..501479e 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -12,7 +12,7 @@ #include <asm/pgtable.h> #include <xen/interface/xen.h> -#include <xen/grant_table.h> +#include <xen/interface/grant_table.h> #include <xen/features.h> /* Xen machine address */ diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 62f591f..94ae0fd 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -776,6 +776,32 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count) } EXPORT_SYMBOL_GPL(gnttab_batch_copy); +void gnttab_foreach_grant_in_range(struct page *page, + unsigned int offset, + unsigned int len, + xen_grant_fn_t fn, + void *data) +{ + unsigned int goffset; + unsigned int glen; + unsigned long xen_pfn; + + len = min_t(unsigned int, PAGE_SIZE - offset, len); + goffset = xen_offset_in_page(offset); + + xen_pfn = xen_page_to_pfn(page) + XEN_PFN_DOWN(offset); + + while (len) { + glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len); + fn(pfn_to_gfn(xen_pfn), goffset, glen, data); + + goffset = 0; + xen_pfn++; + len -= glen; + } +} +EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range); + int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, struct gnttab_map_grant_ref *kmap_ops, struct page **pages, unsigned int count) diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 4478f4b..2a8ebe8 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -45,8 +45,10 @@ #include <asm/xen/hypervisor.h> #include <xen/features.h> +#include <xen/page.h> #include <linux/mm_types.h> #include <linux/page-flags.h> +#include <linux/kernel.h> #define GNTTAB_RESERVED_XENSTORE 1 @@ -224,4 +226,44 @@ static inline struct xen_page_foreign *xen_page_foreign(struct page *page) #endif } +/* Split Linux page in chunk of the size of the grant and call fn + * + * Parameters of fn: + * gfn: guest frame number + * offset: offset in the grant + * len: length of the data in the grant. + * data: internal information + */ +typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset, + unsigned int len, void *data); + +void gnttab_foreach_grant_in_range(struct page *page, + unsigned int offset, + unsigned int len, + xen_grant_fn_t fn, + void *data); + +/* Helper to get to call fn only on the first "grant chunk" */ +static inline void gnttab_one_grant(struct page *page, unsigned int offset, + unsigned len, xen_grant_fn_t fn, + void *data) +{ + /* The first request is limited to the size of one grant */ + len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK), + len); + + gnttab_foreach_grant_in_range(page, offset, len, fn, data); +} + +/* Get the number of grant in a specified region + * + * start: Offset from the beginning of the first page + * len: total length of data (can cross multiple page) + */ +static inline unsigned int gnttab_count_grant(unsigned int start, + unsigned int len) +{ + return XEN_PFN_UP(xen_offset_in_page(start) + len); +} + #endif /* __ASM_GNTTAB_H__ */
Currently, a grant is always based on the Xen page granularity (i.e 4KB). When Linux is using a different page granularity, a single page will be split between multiple grants. The new helpers will be in charge to split the Linux page into grants and call a function given by the caller on each grant. Also provide an helper to count the number of grants within a given contiguous region. Note that the x86/include/asm/xen/page.h is now including xen/interface/grant_table.h rather than xen/grant_table.h. It's necessary because xen/grant_table.h depends on asm/xen/page.h and will break the compilation. Furthermore, only definition in interface/grant_table.h was required. Signed-off-by: Julien Grall <julien.grall@citrix.com> --- Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Changes in v3: - Fix error reported by checkpatch.pl - Typoes - s/pfn/xen_pfn/ in gnttab_foreach_grant - Drop the possibility to use less data. The complexity is moved in netback which is the only user - Rename gnttab_foreach_grant into gnttab_foreach_grant_in_range - s/offset/start/ in gnttab_count_grant and update the description of the parameter - s/mfn/gfn base on the new terminologies - Add EXPORT_SYMBOL_GPL for gnttab_foreach_grant_in_range - Use xen_offset_in_page and XEN_PFN_DOWN whenever it's possible - Fix compilation on x86. Changes in v2: - Patch added --- arch/x86/include/asm/xen/page.h | 2 +- drivers/xen/grant-table.c | 26 +++++++++++++++++++++++++ include/xen/grant_table.h | 42 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 69 insertions(+), 1 deletion(-)