xen: Add xen_create_contiguous_region
A memory region must be physically contiguous in order to be accessed through DMA. This patch adds xen_create_contiguous_region, which ensures a region of contiguous virtual memory is also physically contiguous. Based on Stephen Tweedie's port of the 2.6.18-xen version. Remove contiguous_bitmap[] as it's no longer needed. Ported from linux-2.6.18-xen.hg 707:e410857fd83c [ Impact: add Xen-internal API to make pages phys-contig ] Signed-off-by: Alex Nixon <alex.nixon@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Alex Nixon
Konrad Rzeszutek Wilk
parent
19001c8c5b
commit
08bbc9da92
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@ -53,6 +53,7 @@
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#include <asm/paravirt.h>
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#include <asm/e820.h>
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#include <asm/linkage.h>
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#include <asm/page.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/hypervisor.h>
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@ -2027,6 +2028,206 @@ void __init xen_init_mmu_ops(void)
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pv_mmu_ops = xen_mmu_ops;
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}
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/* Protected by xen_reservation_lock. */
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#define MAX_CONTIG_ORDER 9 /* 2MB */
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static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
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#define VOID_PTE (mfn_pte(0, __pgprot(0)))
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static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
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unsigned long *in_frames,
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unsigned long *out_frames)
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{
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int i;
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struct multicall_space mcs;
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xen_mc_batch();
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for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
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mcs = __xen_mc_entry(0);
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if (in_frames)
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in_frames[i] = virt_to_mfn(vaddr);
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MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
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set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
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if (out_frames)
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out_frames[i] = virt_to_pfn(vaddr);
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}
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xen_mc_issue(0);
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}
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/*
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* Update the pfn-to-mfn mappings for a virtual address range, either to
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* point to an array of mfns, or contiguously from a single starting
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* mfn.
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*/
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static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
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unsigned long *mfns,
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unsigned long first_mfn)
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{
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unsigned i, limit;
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unsigned long mfn;
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xen_mc_batch();
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limit = 1u << order;
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for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
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struct multicall_space mcs;
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unsigned flags;
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mcs = __xen_mc_entry(0);
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if (mfns)
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mfn = mfns[i];
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else
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mfn = first_mfn + i;
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if (i < (limit - 1))
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flags = 0;
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else {
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if (order == 0)
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flags = UVMF_INVLPG | UVMF_ALL;
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else
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flags = UVMF_TLB_FLUSH | UVMF_ALL;
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}
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MULTI_update_va_mapping(mcs.mc, vaddr,
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mfn_pte(mfn, PAGE_KERNEL), flags);
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set_phys_to_machine(virt_to_pfn(vaddr), mfn);
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}
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xen_mc_issue(0);
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}
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/*
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* Perform the hypercall to exchange a region of our pfns to point to
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* memory with the required contiguous alignment. Takes the pfns as
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* input, and populates mfns as output.
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*
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* Returns a success code indicating whether the hypervisor was able to
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* satisfy the request or not.
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*/
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static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
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unsigned long *pfns_in,
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unsigned long extents_out,
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unsigned int order_out,
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unsigned long *mfns_out,
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unsigned int address_bits)
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{
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long rc;
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int success;
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struct xen_memory_exchange exchange = {
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.in = {
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.nr_extents = extents_in,
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.extent_order = order_in,
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.extent_start = pfns_in,
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.domid = DOMID_SELF
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},
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.out = {
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.nr_extents = extents_out,
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.extent_order = order_out,
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.extent_start = mfns_out,
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.address_bits = address_bits,
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.domid = DOMID_SELF
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}
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};
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BUG_ON(extents_in << order_in != extents_out << order_out);
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rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
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success = (exchange.nr_exchanged == extents_in);
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BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
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BUG_ON(success && (rc != 0));
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return success;
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}
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int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
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unsigned int address_bits)
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{
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unsigned long *in_frames = discontig_frames, out_frame;
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unsigned long flags;
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int success;
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/*
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* Currently an auto-translated guest will not perform I/O, nor will
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* it require PAE page directories below 4GB. Therefore any calls to
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* this function are redundant and can be ignored.
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*/
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return 0;
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if (unlikely(order > MAX_CONTIG_ORDER))
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return -ENOMEM;
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memset((void *) vstart, 0, PAGE_SIZE << order);
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vm_unmap_aliases();
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spin_lock_irqsave(&xen_reservation_lock, flags);
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/* 1. Zap current PTEs, remembering MFNs. */
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xen_zap_pfn_range(vstart, order, in_frames, NULL);
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/* 2. Get a new contiguous memory extent. */
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out_frame = virt_to_pfn(vstart);
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success = xen_exchange_memory(1UL << order, 0, in_frames,
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1, order, &out_frame,
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address_bits);
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/* 3. Map the new extent in place of old pages. */
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if (success)
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xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
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else
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xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
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spin_unlock_irqrestore(&xen_reservation_lock, flags);
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return success ? 0 : -ENOMEM;
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}
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EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
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void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
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{
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unsigned long *out_frames = discontig_frames, in_frame;
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unsigned long flags;
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int success;
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return;
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if (unlikely(order > MAX_CONTIG_ORDER))
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return;
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memset((void *) vstart, 0, PAGE_SIZE << order);
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vm_unmap_aliases();
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spin_lock_irqsave(&xen_reservation_lock, flags);
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/* 1. Find start MFN of contiguous extent. */
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in_frame = virt_to_mfn(vstart);
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/* 2. Zap current PTEs. */
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xen_zap_pfn_range(vstart, order, NULL, out_frames);
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/* 3. Do the exchange for non-contiguous MFNs. */
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success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
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0, out_frames, 0);
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/* 4. Map new pages in place of old pages. */
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if (success)
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xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
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else
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xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
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spin_unlock_irqrestore(&xen_reservation_lock, flags);
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}
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EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
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#ifdef CONFIG_XEN_DEBUG_FS
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static struct dentry *d_mmu_debug;
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@ -54,6 +54,48 @@ struct xen_memory_reservation {
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};
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DEFINE_GUEST_HANDLE_STRUCT(xen_memory_reservation);
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/*
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* An atomic exchange of memory pages. If return code is zero then
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* @out.extent_list provides GMFNs of the newly-allocated memory.
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* Returns zero on complete success, otherwise a negative error code.
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* On complete success then always @nr_exchanged == @in.nr_extents.
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* On partial success @nr_exchanged indicates how much work was done.
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*/
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#define XENMEM_exchange 11
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struct xen_memory_exchange {
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/*
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* [IN] Details of memory extents to be exchanged (GMFN bases).
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* Note that @in.address_bits is ignored and unused.
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*/
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struct xen_memory_reservation in;
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/*
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* [IN/OUT] Details of new memory extents.
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* We require that:
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* 1. @in.domid == @out.domid
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* 2. @in.nr_extents << @in.extent_order ==
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* @out.nr_extents << @out.extent_order
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* 3. @in.extent_start and @out.extent_start lists must not overlap
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* 4. @out.extent_start lists GPFN bases to be populated
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* 5. @out.extent_start is overwritten with allocated GMFN bases
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*/
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struct xen_memory_reservation out;
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/*
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* [OUT] Number of input extents that were successfully exchanged:
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* 1. The first @nr_exchanged input extents were successfully
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* deallocated.
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* 2. The corresponding first entries in the output extent list correctly
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* indicate the GMFNs that were successfully exchanged.
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* 3. All other input and output extents are untouched.
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* 4. If not all input exents are exchanged then the return code of this
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* command will be non-zero.
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* 5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER!
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*/
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unsigned long nr_exchanged;
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};
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DEFINE_GUEST_HANDLE_STRUCT(xen_memory_exchange);
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/*
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* Returns the maximum machine frame number of mapped RAM in this system.
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* This command always succeeds (it never returns an error code).
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@ -14,4 +14,10 @@ void xen_mm_unpin_all(void);
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void xen_timer_resume(void);
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void xen_arch_resume(void);
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extern unsigned long *xen_contiguous_bitmap;
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int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
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unsigned int address_bits);
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void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order);
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#endif /* INCLUDE_XEN_OPS_H */
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