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| author | Roger Pau Monne <roger.pau@citrix.com> | 2020-09-01 10:33:26 +0200 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2020-09-04 10:00:01 +0200 |
| commit | 9e2369c06c8a181478039258a4598c1ddd2cadfa (patch) | |
| tree | 4a5834c69de9fb3864acd24e078dd765fb69b21c /drivers/gpu/drm/xen | |
| parent | memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC (diff) | |
| download | linux-9e2369c06c8a181478039258a4598c1ddd2cadfa.tar.xz linux-9e2369c06c8a181478039258a4598c1ddd2cadfa.zip | |
xen: add helpers to allocate unpopulated memory
To be used in order to create foreign mappings. This is based on the
ZONE_DEVICE facility which is used by persistent memory devices in
order to create struct pages and kernel virtual mappings for the IOMEM
areas of such devices. Note that on kernels without support for
ZONE_DEVICE Xen will fallback to use ballooned pages in order to
create foreign mappings.
The newly added helpers use the same parameters as the existing
{alloc/free}_xenballooned_pages functions, which allows for in-place
replacement of the callers. Once a memory region has been added to be
used as scratch mapping space it will no longer be released, and pages
returned are kept in a linked list. This allows to have a buffer of
pages and prevents resorting to frequent additions and removals of
regions.
If enabled (because ZONE_DEVICE is supported) the usage of the new
functionality untangles Xen balloon and RAM hotplug from the usage of
unpopulated physical memory ranges to map foreign pages, which is the
correct thing to do in order to avoid mappings of foreign pages depend
on memory hotplug.
Note the driver is currently not enabled on Arm platforms because it
would interfere with the identity mapping required on some platforms.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20200901083326.21264-4-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/gpu/drm/xen')
| -rw-r--r-- | drivers/gpu/drm/xen/xen_drm_front_gem.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.c b/drivers/gpu/drm/xen/xen_drm_front_gem.c index 39ff95b75357..534daf37c97e 100644 --- a/drivers/gpu/drm/xen/xen_drm_front_gem.c +++ b/drivers/gpu/drm/xen/xen_drm_front_gem.c @@ -18,6 +18,7 @@ #include <drm/drm_probe_helper.h> #include <xen/balloon.h> +#include <xen/xen.h> #include "xen_drm_front.h" #include "xen_drm_front_gem.h" @@ -99,8 +100,8 @@ static struct xen_gem_object *gem_create(struct drm_device *dev, size_t size) * allocate ballooned pages which will be used to map * grant references provided by the backend */ - ret = alloc_xenballooned_pages(xen_obj->num_pages, - xen_obj->pages); + ret = xen_alloc_unpopulated_pages(xen_obj->num_pages, + xen_obj->pages); if (ret < 0) { DRM_ERROR("Cannot allocate %zu ballooned pages: %d\n", xen_obj->num_pages, ret); @@ -152,8 +153,8 @@ void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj) } else { if (xen_obj->pages) { if (xen_obj->be_alloc) { - free_xenballooned_pages(xen_obj->num_pages, - xen_obj->pages); + xen_free_unpopulated_pages(xen_obj->num_pages, + xen_obj->pages); gem_free_pages_array(xen_obj); } else { drm_gem_put_pages(&xen_obj->base, |