From: Quentin Perret <qperret@xxxxxxxxxx>
All the contiguous pages used to initialize a hyp_pool are considered
coalescable, which means that the hyp page allocator will actively
try to merge them with their buddies on the hyp_put_page() path.
However, using hyp_put_page() on a page that is not part of the inital
memory range given to a hyp_pool() is currently unsupported.
In order to allow dynamically extending hyp pools at run-time, add a
check to __hyp_attach_page() to allow inserting 'external' pages into
the free-list of order 0. This will be necessary to allow lazy
donation of pages from the host to the hypervisor when allocating guest
stage-2 page-table pages at EL2.
Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/kvm/hyp/nvhe/page_alloc.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
index 1ded09fc9b10..0d15227aced8 100644
--- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
@@ -93,11 +93,15 @@ static inline struct hyp_page *node_to_page(struct list_head *node)
static void __hyp_attach_page(struct hyp_pool *pool,
struct hyp_page *p)
{
+ phys_addr_t phys = hyp_page_to_phys(p);
unsigned short order = p->order;
struct hyp_page *buddy;
memset(hyp_page_to_virt(p), 0, PAGE_SIZE << p->order);
+ if (phys < pool->range_start || phys >= pool->range_end)
+ goto insert;
+
/*
* Only the first struct hyp_page of a high-order page (otherwise known
* as the 'head') should have p->order set. The non-head pages should
@@ -116,6 +120,7 @@ static void __hyp_attach_page(struct hyp_pool *pool,
p = min(p, buddy);
}
+insert:
/* Mark the new head, and insert it */
p->order = order;
page_add_to_list(p, &pool->free_area[order]);
--
2.37.0.rc0.161.g10f37bed90-goog
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