From: Quentin Perret Date: Thu, 10 Nov 2022 19:02:35 +0000 (+0000) Subject: KVM: arm64: Allow attaching of non-coalescable pages to a hyp pool X-Git-Tag: v6.6.17~5910^2~4^2~4^2~23 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=72a5bc0f153ce8ca80e9abbd1d9adec7d586915a;p=platform%2Fkernel%2Flinux-rpi.git KVM: arm64: Allow attaching of non-coalescable pages to a hyp pool All the contiguous pages used to initialize a 'struct 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. Tested-by: Vincent Donnefort Signed-off-by: Quentin Perret Signed-off-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221110190259.26861-3-will@kernel.org --- diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c index 1ded09f..dad88e2 100644 --- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c +++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c @@ -93,11 +93,16 @@ 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); + /* Skip coalescing for 'external' pages being freed into the pool. */ + 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 +121,7 @@ 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]);