lwn.git/drivers/xen/grant-table.c, branch docs-4.14

xen/grant-table: log the lack of grants

2017-07-23T06:09:43+00:00

log a message when we enter this situation: 1) we already allocated the max number of available grants from hypervisor and 2) we still need more (but the request fails because of 1)). Sometimes the lack of grants causes IO hangs in xen_blkfront devices. Adding this log would help debuging. Signed-off-by: Wengang Wang Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Junxiao Bi Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

xen/pvh: Initialize grant table for PVH guests

2017-02-07T13:07:01+00:00

Like PV guests, PVH does not have PCI devices and therefore cannot use MMIO space to store grants. Instead it balloons out memory and keeps grants there. Signed-off-by: Boris Ostrovsky Reviewed-by: Juergen Gross

xen: audit usages of module.h ; remove unnecessary instances

2016-03-21T15:13:32+00:00

Code that uses no modular facilities whatsoever should not be sourcing module.h at all, since that header drags in a bunch of other headers with it. Similarly, code that is not explicitly using modular facilities like module_init() but only is declaring module_param setup variables should be using moduleparam.h and not the larger module.h file for that. In making this change, we also uncover an implicit use of BUG() in inline fcns within arch/arm/include/asm/xen/hypercall.h so we explicitly source for that file now. Signed-off-by: Paul Gortmaker Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel

xen/grant-table: constify gnttab_ops structure

2015-12-21T14:41:01+00:00

The gnttab_ops structure is never modified, so declare it as const. Done with the help of Coccinelle. Signed-off-by: Julia Lawall Signed-off-by: David Vrabel

xen/grant-table: Add an helper to iterate over a specific number of grants

2015-10-23T13:20:46+00:00

With the 64KB page granularity support on ARM64, a Linux page may be split accross multiple grant. Currently we have the helper gnttab_foreach_grant_in_grant to break a Linux page based on an offset and a len, but it doesn't fit when we only have a number of grants in hand. Introduce a new helper which take an array of Linux page and a number of grant and will figure out the address of each grant. Signed-off-by: Julien Grall Signed-off-by: David Vrabel

xen/grant-table: Make it running on 64KB granularity

2015-10-23T13:20:39+00:00

The Xen interface is using 4KB page granularity. This means that each grant is 4KB. The current implementation allocates a Linux page per grant. On Linux using 64KB page granularity, only the first 4KB of the page will be used. We could decrease the memory wasted by sharing the page with multiple grant. It will require some care with the {Set,Clear}ForeignPage macro. Note that no changes has been made in the x86 code because both Linux and Xen will only use 4KB page granularity. Signed-off-by: Julien Grall Reviewed-by: David Vrabel Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel

xen/grant: Introduce helpers to split a page into grant

2015-10-23T13:20:33+00:00

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 of splitting 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 is required. Signed-off-by: Julien Grall Reviewed-by: David Vrabel Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel

xen/balloon: make alloc_xenballoon_pages() always allocate low pages

2015-10-23T13:20:05+00:00

All users of alloc_xenballoon_pages() wanted low memory pages, so remove the option for high memory. Signed-off-by: David Vrabel Reviewed-by: Daniel Kiper

xen/grant-table: Remove unused macro SPP

2015-06-17T15:15:19+00:00

SPP was used by the grant table v2 code which has been removed in commit 438b33c7145ca8a5131a30c36d8f59bce119a19a "xen/grant-table: remove support for V2 tables". Signed-off-by: Julien Grall Reviewed-by: David Vrabel Cc: Konrad Rzeszutek Wilk Cc: Boris Ostrovsky Signed-off-by: David Vrabel

xen/grant: introduce func gnttab_unmap_refs_sync()

2015-04-27T10:41:12+00:00

There are several place using gnttab async unmap and wait for completion, so move the common code to a function gnttab_unmap_refs_sync(). Signed-off-by: Bob Liu Acked-by: Roger Pau Monné Acked-by: Konrad Rzeszutek Wilk Signed-off-by: David Vrabel