Commit 08bbc9da authored by Alex Nixon's avatar Alex Nixon Committed by Konrad Rzeszutek Wilk
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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: default avatarAlex Nixon <alex.nixon@citrix.com>
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 19001c8c
......@@ -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;
......
......@@ -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).
......
......@@ -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 */
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