Re: [RFC PATCH v2 12/26] KVM: arm64: Introduce a Hyp buddy page allocator
From: Quentin Perret <hidden>
Date: 2021-02-04 14:56:21
Also in:
kvmarm, linux-devicetree, lkml
On Thursday 04 Feb 2021 at 14:31:08 (+0000), Will Deacon wrote:
On Wed, Feb 03, 2021 at 06:33:30PM +0000, Quentin Perret wrote:quoted
On Tuesday 02 Feb 2021 at 18:13:08 (+0000), Will Deacon wrote:quoted
On Fri, Jan 08, 2021 at 12:15:10PM +0000, Quentin Perret wrote:quoted
+ * __find_buddy(pool, page 0, order 0) => page 1 + * __find_buddy(pool, page 0, order 1) => page 2 + * __find_buddy(pool, page 1, order 0) => page 0 + * __find_buddy(pool, page 2, order 0) => page 3 + */ +static struct hyp_page *__find_buddy(struct hyp_pool *pool, struct hyp_page *p, + unsigned int order) +{ + phys_addr_t addr = hyp_page_to_phys(p); + + addr ^= (PAGE_SIZE << order); + if (addr < pool->range_start || addr >= pool->range_end) + return NULL;Are these range checks only needed because the pool isn't required to be an exact power-of-2 pages in size? If so, maybe it would be more straightforward to limit the max order on a per-pool basis depending upon its size?More importantly, it is because pages outside of the pool are not guaranteed to be covered by the hyp_vmemmap, so I really need to make sure I don't dereference them.Wouldn't having a per-pool max order help with that?
The issue is, I have no alignment guarantees for the pools, so I may end up with max_order = 0 ... _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel