ae4c51a50c
Memory {increase|decrease}_reservation and VA mappings update/reset
code used in balloon driver can be made common, so other drivers can
also re-use the same functionality without open-coding.
Create a dedicated file for the shared code and export corresponding
symbols for other kernel modules.
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
118 lines
3 KiB
C
118 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/******************************************************************************
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* Xen memory reservation utilities.
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*
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* Copyright (c) 2003, B Dragovic
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* Copyright (c) 2003-2004, M Williamson, K Fraser
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* Copyright (c) 2005 Dan M. Smith, IBM Corporation
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* Copyright (c) 2010 Daniel Kiper
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* Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
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*/
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#include <asm/xen/hypercall.h>
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#include <xen/interface/memory.h>
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#include <xen/mem-reservation.h>
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/*
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* Use one extent per PAGE_SIZE to avoid to break down the page into
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* multiple frame.
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*/
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#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)
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#ifdef CONFIG_XEN_HAVE_PVMMU
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void __xenmem_reservation_va_mapping_update(unsigned long count,
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struct page **pages,
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xen_pfn_t *frames)
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{
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int i;
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for (i = 0; i < count; i++) {
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struct page *page = pages[i];
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unsigned long pfn = page_to_pfn(page);
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BUG_ON(!page);
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/*
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* We don't support PV MMU when Linux and Xen is using
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* different page granularity.
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*/
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BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
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set_phys_to_machine(pfn, frames[i]);
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/* Link back into the page tables if not highmem. */
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if (!PageHighMem(page)) {
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int ret;
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ret = HYPERVISOR_update_va_mapping(
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(unsigned long)__va(pfn << PAGE_SHIFT),
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mfn_pte(frames[i], PAGE_KERNEL),
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0);
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BUG_ON(ret);
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}
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}
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}
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EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_update);
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void __xenmem_reservation_va_mapping_reset(unsigned long count,
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struct page **pages)
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{
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int i;
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for (i = 0; i < count; i++) {
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struct page *page = pages[i];
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unsigned long pfn = page_to_pfn(page);
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/*
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* We don't support PV MMU when Linux and Xen are using
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* different page granularity.
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*/
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BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
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if (!PageHighMem(page)) {
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int ret;
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ret = HYPERVISOR_update_va_mapping(
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(unsigned long)__va(pfn << PAGE_SHIFT),
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__pte_ma(0), 0);
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BUG_ON(ret);
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}
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__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
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}
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}
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EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_reset);
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#endif /* CONFIG_XEN_HAVE_PVMMU */
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/* @frames is an array of PFNs */
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int xenmem_reservation_increase(int count, xen_pfn_t *frames)
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{
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struct xen_memory_reservation reservation = {
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.address_bits = 0,
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.extent_order = EXTENT_ORDER,
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.domid = DOMID_SELF
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};
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/* XENMEM_populate_physmap requires a PFN based on Xen granularity. */
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set_xen_guest_handle(reservation.extent_start, frames);
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reservation.nr_extents = count;
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return HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
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}
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EXPORT_SYMBOL_GPL(xenmem_reservation_increase);
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/* @frames is an array of GFNs */
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int xenmem_reservation_decrease(int count, xen_pfn_t *frames)
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{
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struct xen_memory_reservation reservation = {
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.address_bits = 0,
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.extent_order = EXTENT_ORDER,
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.domid = DOMID_SELF
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};
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/* XENMEM_decrease_reservation requires a GFN */
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set_xen_guest_handle(reservation.extent_start, frames);
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reservation.nr_extents = count;
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return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
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}
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EXPORT_SYMBOL_GPL(xenmem_reservation_decrease);
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