Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754759AbbGIUqp (ORCPT ); Thu, 9 Jul 2015 16:46:45 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:2082 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754073AbbGIUqE (ORCPT ); Thu, 9 Jul 2015 16:46:04 -0400 X-IronPort-AV: E=Sophos;i="5.15,442,1432598400"; d="scan'208";a="282742101" From: Julien Grall To: CC: , , , , "Julien Grall" , Konrad Rzeszutek Wilk , Boris Ostrovsky , "David Vrabel" , Wei Liu Subject: [PATCH v2 12/20] xen/balloon: Don't rely on the page granularity is the same for Xen and Linux Date: Thu, 9 Jul 2015 21:42:24 +0100 Message-ID: <1436474552-31789-13-git-send-email-julien.grall@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> References: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> MIME-Version: 1.0 Content-Type: text/plain X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8362 Lines: 287 For ARM64 guests, Linux is able to support either 64K or 4K page granularity. Although, the hypercall interface is always based on 4K page granularity. With 64K page granuliarty, a single page will be spread over multiple Xen frame. When a driver request/free a balloon page, the balloon driver will have to split the Linux page in 4K chunk before asking Xen to add/remove the frame from the guest. Note that this can work on any page granularity assuming it's a multiple of 4K. Signed-off-by: Julien Grall Cc: Konrad Rzeszutek Wilk Cc: Boris Ostrovsky Cc: David Vrabel Cc: Wei Liu --- Changes in v2: - Use xen_apply_to_page to split a page in 4K chunk - It's not necessary to have a smaller frame list. Re-use PAGE_SIZE - Convert reserve_additional_memory to use XEN_... macro --- drivers/xen/balloon.c | 147 +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 105 insertions(+), 42 deletions(-) diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index fd93369..19a72b1 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -230,6 +230,7 @@ static enum bp_state reserve_additional_memory(long credit) nid = memory_add_physaddr_to_nid(hotplug_start_paddr); #ifdef CONFIG_XEN_HAVE_PVMMU + /* TODO */ /* * add_memory() will build page tables for the new memory so * the p2m must contain invalid entries so the correct @@ -242,8 +243,8 @@ static enum bp_state reserve_additional_memory(long credit) if (!xen_feature(XENFEAT_auto_translated_physmap)) { unsigned long pfn, i; - pfn = PFN_DOWN(hotplug_start_paddr); - for (i = 0; i < balloon_hotplug; i++) { + pfn = XEN_PFN_DOWN(hotplug_start_paddr); + for (i = 0; i < (balloon_hotplug * XEN_PFN_PER_PAGE); i++) { if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { pr_warn("set_phys_to_machine() failed, no memory added\n"); return BP_ECANCELED; @@ -323,10 +324,72 @@ static enum bp_state reserve_additional_memory(long credit) } #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ +static int set_frame(struct page *page, unsigned long pfn, void *data) +{ + unsigned long *index = data; + + frame_list[(*index)++] = pfn; + + return 0; +} + +#ifdef CONFIG_XEN_HAVE_PVMMU +static int pvmmu_update_mapping(struct page *page, unsigned long pfn, + void *data) +{ + unsigned long *index = data; + xen_pfn_t frame = frame_list[*index]; + + set_phys_to_machine(pfn, frame); + /* Link back into the page tables if not highmem. */ + if (!PageHighMem(page)) { + int ret; + ret = HYPERVISOR_update_va_mapping( + (unsigned long)__va(pfn << XEN_PAGE_SHIFT), + mfn_pte(frame, PAGE_KERNEL), + 0); + BUG_ON(ret); + } + + (*index)++; + + return 0; +} +#endif + +static int balloon_remove_mapping(struct page *page, unsigned long pfn, + void *data) +{ + unsigned long *index = data; + + /* We expect the frame_list to contain the same pfn */ + BUG_ON(pfn != frame_list[*index]); + + frame_list[*index] = pfn_to_mfn(pfn); + +#ifdef CONFIG_XEN_HAVE_PVMMU + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + if (!PageHighMem(page)) { + int ret; + + ret = HYPERVISOR_update_va_mapping( + (unsigned long)__va(pfn << XEN_PAGE_SHIFT), + __pte_ma(0), 0); + BUG_ON(ret); + } + __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); + } +#endif + + (*index)++; + + return 0; +} + static enum bp_state increase_reservation(unsigned long nr_pages) { int rc; - unsigned long pfn, i; + unsigned long i, frame_idx; struct page *page; struct xen_memory_reservation reservation = { .address_bits = 0, @@ -343,44 +406,43 @@ static enum bp_state increase_reservation(unsigned long nr_pages) } #endif - if (nr_pages > ARRAY_SIZE(frame_list)) - nr_pages = ARRAY_SIZE(frame_list); + if (nr_pages > (ARRAY_SIZE(frame_list) / XEN_PFN_PER_PAGE)) + nr_pages = ARRAY_SIZE(frame_list) / XEN_PFN_PER_PAGE; + frame_idx = 0; page = list_first_entry_or_null(&ballooned_pages, struct page, lru); for (i = 0; i < nr_pages; i++) { if (!page) { nr_pages = i; break; } - frame_list[i] = page_to_pfn(page); + + rc = xen_apply_to_page(page, set_frame, &frame_idx); + page = balloon_next_page(page); } set_xen_guest_handle(reservation.extent_start, frame_list); - reservation.nr_extents = nr_pages; + reservation.nr_extents = nr_pages * XEN_PFN_PER_PAGE; rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); if (rc <= 0) return BP_EAGAIN; - for (i = 0; i < rc; i++) { + /* rc is equal to the number of Xen page populated */ + nr_pages = rc / XEN_PFN_PER_PAGE; + + for (i = 0; i < nr_pages; i++) { page = balloon_retrieve(false); BUG_ON(page == NULL); - pfn = page_to_pfn(page); - #ifdef CONFIG_XEN_HAVE_PVMMU + frame_idx = 0; if (!xen_feature(XENFEAT_auto_translated_physmap)) { - set_phys_to_machine(pfn, frame_list[i]); - - /* Link back into the page tables if not highmem. */ - if (!PageHighMem(page)) { - int ret; - ret = HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), - mfn_pte(frame_list[i], PAGE_KERNEL), - 0); - BUG_ON(ret); - } + int ret; + + ret = xen_apply_to_page(page, pvmmu_update_mapping, + &frame_idx); + BUG_ON(ret); } #endif @@ -388,7 +450,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages) __free_reserved_page(page); } - balloon_stats.current_pages += rc; + balloon_stats.current_pages += nr_pages; return BP_DONE; } @@ -396,7 +458,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages) static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) { enum bp_state state = BP_DONE; - unsigned long pfn, i; + unsigned long pfn, i, frame_idx, nr_frames; struct page *page; int ret; struct xen_memory_reservation reservation = { @@ -414,9 +476,10 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) } #endif - if (nr_pages > ARRAY_SIZE(frame_list)) - nr_pages = ARRAY_SIZE(frame_list); + if (nr_pages > (ARRAY_SIZE(frame_list) / XEN_PFN_PER_PAGE)) + nr_pages = ARRAY_SIZE(frame_list) / XEN_PFN_PER_PAGE; + frame_idx = 0; for (i = 0; i < nr_pages; i++) { page = alloc_page(gfp); if (page == NULL) { @@ -426,9 +489,12 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) } scrub_page(page); - frame_list[i] = page_to_pfn(page); + ret = xen_apply_to_page(page, set_frame, &frame_idx); + BUG_ON(ret); } + nr_frames = nr_pages * XEN_PFN_PER_PAGE; + /* * Ensure that ballooned highmem pages don't have kmaps. * @@ -439,22 +505,19 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) kmap_flush_unused(); /* Update direct mapping, invalidate P2M, and add to balloon. */ + frame_idx = 0; for (i = 0; i < nr_pages; i++) { - pfn = frame_list[i]; - frame_list[i] = pfn_to_mfn(pfn); - page = pfn_to_page(pfn); + /* + * The Xen PFN for a given Linux Page are contiguous in + * frame_list + */ + pfn = frame_list[frame_idx]; + page = xen_pfn_to_page(pfn); -#ifdef CONFIG_XEN_HAVE_PVMMU - if (!xen_feature(XENFEAT_auto_translated_physmap)) { - if (!PageHighMem(page)) { - ret = HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), - __pte_ma(0), 0); - BUG_ON(ret); - } - __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); - } -#endif + + ret = xen_apply_to_page(page, balloon_remove_mapping, + &frame_idx); + BUG_ON(ret); balloon_append(page); } @@ -462,9 +525,9 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) flush_tlb_all(); set_xen_guest_handle(reservation.extent_start, frame_list); - reservation.nr_extents = nr_pages; + reservation.nr_extents = nr_frames; ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); - BUG_ON(ret != nr_pages); + BUG_ON(ret != nr_frames); balloon_stats.current_pages -= nr_pages; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/