[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v10 8/9] xen: retrieve reserved pages on populate_physmap
When a static domain populates memory through populate_physmap at runtime, it shall retrieve reserved pages from resv_page_list to make sure that guest RAM is still restricted in statically configured memory regions. This commit also introduces a new helper acquire_reserved_page to make it work. Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx> --- v10 changes: - add lock on the fail path --- v9 changes: - Use ASSERT_ALLOC_CONTEXT() in acquire_reserved_page - Add free_staticmem_pages to undo prepare_staticmem_pages when assign_domstatic_pages - Remove redundant static in error message --- v8 changes: - As concurrent free/allocate could modify the resv_page_list, we still need the lock --- v7 changes: - remove the lock, since we add the page to rsv_page_list after it has been totally freed. --- v6 changes: - drop the lock before returning --- v5 changes: - extract common codes for assigning pages into a helper assign_domstatic_pages - refine commit message - remove stub function acquire_reserved_page - Alloc/free of memory can happen concurrently. So access to rsv_page_list needs to be protected with a spinlock --- v4 changes: - miss dropping __init in acquire_domstatic_pages - add the page back to the reserved list in case of error - remove redundant printk - refine log message and make it warn level --- v3 changes: - move is_domain_using_staticmem to the common header file - remove #ifdef CONFIG_STATIC_MEMORY-ary - remove meaningless page_to_mfn(page) in error log --- v2 changes: - introduce acquire_reserved_page to retrieve reserved pages from resv_page_list - forbid non-zero-order requests in populate_physmap - let is_domain_static return ((void)(d), false) on x86 --- xen/common/memory.c | 23 +++++++++++++ xen/common/page_alloc.c | 76 ++++++++++++++++++++++++++++++++--------- xen/include/xen/mm.h | 1 + 3 files changed, 83 insertions(+), 17 deletions(-) diff --git a/xen/common/memory.c b/xen/common/memory.c index bc89442ba5..ae8163a738 100644 --- a/xen/common/memory.c +++ b/xen/common/memory.c @@ -245,6 +245,29 @@ static void populate_physmap(struct memop_args *a) mfn = _mfn(gpfn); } + else if ( is_domain_using_staticmem(d) ) + { + /* + * No easy way to guarantee the retrieved pages are contiguous, + * so forbid non-zero-order requests here. + */ + if ( a->extent_order != 0 ) + { + gdprintk(XENLOG_WARNING, + "Cannot allocate static order-%u pages for %pd\n", + a->extent_order, d); + goto out; + } + + mfn = acquire_reserved_page(d, a->memflags); + if ( mfn_eq(mfn, INVALID_MFN) ) + { + gdprintk(XENLOG_WARNING, + "%pd: failed to retrieve a reserved page\n", + d); + goto out; + } + } else { page = alloc_domheap_pages(d, a->extent_order, a->memflags); diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 0ee697705c..9c6d369d10 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -2751,9 +2751,8 @@ void free_domstatic_page(struct page_info *page) put_domain(d); } -static bool __init prepare_staticmem_pages(struct page_info *pg, - unsigned long nr_mfns, - unsigned int memflags) +static bool prepare_staticmem_pages(struct page_info *pg, unsigned long nr_mfns, + unsigned int memflags) { bool need_tlbflush = false; uint32_t tlbflush_timestamp = 0; @@ -2834,21 +2833,9 @@ static struct page_info * __init acquire_staticmem_pages(mfn_t smfn, return pg; } -/* - * Acquire nr_mfns contiguous pages, starting at #smfn, of static memory, - * then assign them to one specific domain #d. - */ -int __init acquire_domstatic_pages(struct domain *d, mfn_t smfn, - unsigned int nr_mfns, unsigned int memflags) +static int assign_domstatic_pages(struct domain *d, struct page_info *pg, + unsigned int nr_mfns, unsigned int memflags) { - struct page_info *pg; - - ASSERT_ALLOC_CONTEXT(); - - pg = acquire_staticmem_pages(smfn, nr_mfns, memflags); - if ( !pg ) - return -ENOENT; - if ( !d || (memflags & (MEMF_no_owner | MEMF_no_refcount)) ) { /* @@ -2867,6 +2854,61 @@ int __init acquire_domstatic_pages(struct domain *d, mfn_t smfn, return 0; } + +/* + * Acquire nr_mfns contiguous pages, starting at #smfn, of static memory, + * then assign them to one specific domain #d. + */ +int __init acquire_domstatic_pages(struct domain *d, mfn_t smfn, + unsigned int nr_mfns, unsigned int memflags) +{ + struct page_info *pg; + + ASSERT_ALLOC_CONTEXT(); + + pg = acquire_staticmem_pages(smfn, nr_mfns, memflags); + if ( !pg ) + return -ENOENT; + + if ( assign_domstatic_pages(d, pg, nr_mfns, memflags) ) + return -EINVAL; + + return 0; +} + +/* + * Acquire a page from reserved page list(resv_page_list), when populating + * memory for static domain on runtime. + */ +mfn_t acquire_reserved_page(struct domain *d, unsigned int memflags) +{ + struct page_info *page; + + ASSERT_ALLOC_CONTEXT(); + + /* Acquire a page from reserved page list(resv_page_list). */ + spin_lock(&d->page_alloc_lock); + page = page_list_remove_head(&d->resv_page_list); + spin_unlock(&d->page_alloc_lock); + if ( unlikely(!page) ) + return INVALID_MFN; + + if ( !prepare_staticmem_pages(page, 1, memflags) ) + goto fail; + + if ( assign_domstatic_pages(d, page, 1, memflags) ) + goto fail_assign; + + return page_to_mfn(page); + + fail_assign: + free_staticmem_pages(page, 1, memflags & MEMF_no_scrub); + fail: + spin_lock(&d->page_alloc_lock); + page_list_add_tail(page, &d->resv_page_list); + spin_unlock(&d->page_alloc_lock); + return INVALID_MFN; +} #endif /* diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h index deadf4b2a1..5d29aea7ad 100644 --- a/xen/include/xen/mm.h +++ b/xen/include/xen/mm.h @@ -198,6 +198,7 @@ struct npfec { #else #define MAX_ORDER 20 /* 2^20 contiguous pages */ #endif +mfn_t acquire_reserved_page(struct domain *d, unsigned int memflags); /* Private domain structs for DOMID_XEN, DOMID_IO, etc. */ extern struct domain *dom_xen, *dom_io; -- 2.25.1
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