xen: Add xen_create_contiguous_region (08bbc9da) · Commits · 戴 / test

arch/x86/xen/mmu.c

+201 −0

Original line number	Diff line number	Diff line
		@@ -53,6 +53,7 @@
		#include <asm/paravirt.h>
		#include <asm/e820.h>
		#include <asm/linkage.h>
		#include <asm/page.h>

		#include <asm/xen/hypercall.h>
		#include <asm/xen/hypervisor.h>
		@@ -2027,6 +2028,206 @@ void __init xen_init_mmu_ops(void)
		pv_mmu_ops = xen_mmu_ops;
		}

		/* Protected by xen_reservation_lock. */
		#define MAX_CONTIG_ORDER 9 /* 2MB */
		static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];

		#define VOID_PTE (mfn_pte(0, __pgprot(0)))
		static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
		unsigned long *in_frames,
		unsigned long *out_frames)
		{
		int i;
		struct multicall_space mcs;

		xen_mc_batch();
		for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
		mcs = __xen_mc_entry(0);

		if (in_frames)
		in_frames[i] = virt_to_mfn(vaddr);

		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
		set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);

		if (out_frames)
		out_frames[i] = virt_to_pfn(vaddr);
		}
		xen_mc_issue(0);
		}

		/*
		* Update the pfn-to-mfn mappings for a virtual address range, either to
		* point to an array of mfns, or contiguously from a single starting
		* mfn.
		*/
		static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
		unsigned long *mfns,
		unsigned long first_mfn)
		{
		unsigned i, limit;
		unsigned long mfn;

		xen_mc_batch();

		limit = 1u << order;
		for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
		struct multicall_space mcs;
		unsigned flags;

		mcs = __xen_mc_entry(0);
		if (mfns)
		mfn = mfns[i];
		else
		mfn = first_mfn + i;

		if (i < (limit - 1))
		flags = 0;
		else {
		if (order == 0)
		flags = UVMF_INVLPG \| UVMF_ALL;
		else
		flags = UVMF_TLB_FLUSH \| UVMF_ALL;
		}

		MULTI_update_va_mapping(mcs.mc, vaddr,
		mfn_pte(mfn, PAGE_KERNEL), flags);

		set_phys_to_machine(virt_to_pfn(vaddr), mfn);
		}

		xen_mc_issue(0);
		}

		/*
		* Perform the hypercall to exchange a region of our pfns to point to
		* memory with the required contiguous alignment. Takes the pfns as
		* input, and populates mfns as output.
		*
		* Returns a success code indicating whether the hypervisor was able to
		* satisfy the request or not.
		*/
		static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
		unsigned long *pfns_in,
		unsigned long extents_out,
		unsigned int order_out,
		unsigned long *mfns_out,
		unsigned int address_bits)
		{
		long rc;
		int success;

		struct xen_memory_exchange exchange = {
		.in = {
		.nr_extents = extents_in,
		.extent_order = order_in,
		.extent_start = pfns_in,
		.domid = DOMID_SELF
		},
		.out = {
		.nr_extents = extents_out,
		.extent_order = order_out,
		.extent_start = mfns_out,
		.address_bits = address_bits,
		.domid = DOMID_SELF
		}
		};

		BUG_ON(extents_in << order_in != extents_out << order_out);

		rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
		success = (exchange.nr_exchanged == extents_in);

		BUG_ON(!success && ((exchange.nr_exchanged != 0) \|\| (rc == 0)));
		BUG_ON(success && (rc != 0));

		return success;
		}

		int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
		unsigned int address_bits)
		{
		unsigned long *in_frames = discontig_frames, out_frame;
		unsigned long flags;
		int success;

		/*
		* Currently an auto-translated guest will not perform I/O, nor will
		* it require PAE page directories below 4GB. Therefore any calls to
		* this function are redundant and can be ignored.
		*/

		if (xen_feature(XENFEAT_auto_translated_physmap))
		return 0;

		if (unlikely(order > MAX_CONTIG_ORDER))
		return -ENOMEM;

		memset((void *) vstart, 0, PAGE_SIZE << order);

		vm_unmap_aliases();

		spin_lock_irqsave(&xen_reservation_lock, flags);

		/* 1. Zap current PTEs, remembering MFNs. */
		xen_zap_pfn_range(vstart, order, in_frames, NULL);

		/* 2. Get a new contiguous memory extent. */
		out_frame = virt_to_pfn(vstart);
		success = xen_exchange_memory(1UL << order, 0, in_frames,
		1, order, &out_frame,
		address_bits);

		/* 3. Map the new extent in place of old pages. */
		if (success)
		xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
		else
		xen_remap_exchanged_ptes(vstart, order, in_frames, 0);

		spin_unlock_irqrestore(&xen_reservation_lock, flags);

		return success ? 0 : -ENOMEM;
		}
		EXPORT_SYMBOL_GPL(xen_create_contiguous_region);

		void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
		{
		unsigned long *out_frames = discontig_frames, in_frame;
		unsigned long flags;
		int success;

		if (xen_feature(XENFEAT_auto_translated_physmap))
		return;

		if (unlikely(order > MAX_CONTIG_ORDER))
		return;

		memset((void *) vstart, 0, PAGE_SIZE << order);

		vm_unmap_aliases();

		spin_lock_irqsave(&xen_reservation_lock, flags);

		/* 1. Find start MFN of contiguous extent. */
		in_frame = virt_to_mfn(vstart);

		/* 2. Zap current PTEs. */
		xen_zap_pfn_range(vstart, order, NULL, out_frames);

		/* 3. Do the exchange for non-contiguous MFNs. */
		success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
		0, out_frames, 0);

		/* 4. Map new pages in place of old pages. */
		if (success)
		xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
		else
		xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);

		spin_unlock_irqrestore(&xen_reservation_lock, flags);
		}
		EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);

		#ifdef CONFIG_XEN_DEBUG_FS

		static struct dentry *d_mmu_debug;

include/xen/interface/memory.h

+42 −0

Original line number	Diff line number	Diff line
		@@ -54,6 +54,48 @@ struct xen_memory_reservation {
		};
		DEFINE_GUEST_HANDLE_STRUCT(xen_memory_reservation);

		/*
		* An atomic exchange of memory pages. If return code is zero then
		* @out.extent_list provides GMFNs of the newly-allocated memory.
		* Returns zero on complete success, otherwise a negative error code.
		* On complete success then always @nr_exchanged == @in.nr_extents.
		* On partial success @nr_exchanged indicates how much work was done.
		*/
		#define XENMEM_exchange 11
		struct xen_memory_exchange {
		/*
		* [IN] Details of memory extents to be exchanged (GMFN bases).
		* Note that @in.address_bits is ignored and unused.
		*/
		struct xen_memory_reservation in;

		/*
		* [IN/OUT] Details of new memory extents.
		* We require that:
		* 1. @in.domid == @out.domid
		* 2. @in.nr_extents << @in.extent_order ==
		* @out.nr_extents << @out.extent_order
		* 3. @in.extent_start and @out.extent_start lists must not overlap
		* 4. @out.extent_start lists GPFN bases to be populated
		* 5. @out.extent_start is overwritten with allocated GMFN bases
		*/
		struct xen_memory_reservation out;

		/*
		* [OUT] Number of input extents that were successfully exchanged:
		* 1. The first @nr_exchanged input extents were successfully
		* deallocated.
		* 2. The corresponding first entries in the output extent list correctly
		* indicate the GMFNs that were successfully exchanged.
		* 3. All other input and output extents are untouched.
		* 4. If not all input exents are exchanged then the return code of this
		* command will be non-zero.
		* 5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER!
		*/
		unsigned long nr_exchanged;
		};

		DEFINE_GUEST_HANDLE_STRUCT(xen_memory_exchange);
		/*
		* Returns the maximum machine frame number of mapped RAM in this system.
		* This command always succeeds (it never returns an error code).

include/xen/xen-ops.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -14,4 +14,10 @@ void xen_mm_unpin_all(void);
		void xen_timer_resume(void);
		void xen_arch_resume(void);

		extern unsigned long *xen_contiguous_bitmap;
		int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
		unsigned int address_bits);

		void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order);

		#endif /* INCLUDE_XEN_OPS_H */

Admin message