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Commit 1b65c4e5 authored by Stefano Stabellini's avatar Stefano Stabellini
Browse files

swiotlb-xen: use xen_alloc/free_coherent_pages 



Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or
free coherent pages.

We need to be careful handling the pointer returned by
xen_alloc_coherent_pages, because on ARM the pointer is not equal to
phys_to_virt(*dma_handle). In fact virt_to_phys only works for kernel
direct mapped RAM memory.
In ARM case the pointer could be an ioremap address, therefore passing
it to virt_to_phys would give you another physical address that doesn't
correspond to it.

Make xen_create_contiguous_region take a phys_addr_t as start parameter to
avoid the virt_to_phys calls which would be incorrect.

Changes in v6:
- remove extra spaces.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent d6fe76c5

arch/arm/xen/mm.c

+3 −3
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 
#include <asm/xen/hypercall.h>

#include <asm/xen/interface.h>



int xen_create_contiguous_region(unsigned long vstart, unsigned int order,

int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,

				 unsigned int address_bits,

				 dma_addr_t *dma_handle)

{
@@ -24,12 +24,12 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order, 
		return -EINVAL;



	/* we assume that dom0 is mapped 1:1 for now */

	*dma_handle = virt_to_phys(pstart);

	*dma_handle = pstart;

	return 0;

}

EXPORT_SYMBOL_GPL(xen_create_contiguous_region);



void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)

void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)

{

	return;

}

arch/x86/xen/mmu.c

+5 −2
Original line number Diff line number Diff line
@@ -2328,13 +2328,14 @@ static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in, 
	return success;

}



int xen_create_contiguous_region(unsigned long vstart, unsigned int order,

int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,

				 unsigned int address_bits,

				 dma_addr_t *dma_handle)

{

	unsigned long *in_frames = discontig_frames, out_frame;

	unsigned long  flags;

	int            success;

	unsigned long vstart = (unsigned long)phys_to_virt(pstart);



	/*

	 * Currently an auto-translated guest will not perform I/O, nor will
@@ -2374,11 +2375,12 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order, 
}

EXPORT_SYMBOL_GPL(xen_create_contiguous_region);



void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)

void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)

{

	unsigned long *out_frames = discontig_frames, in_frame;

	unsigned long  flags;

	int success;

	unsigned long vstart;



	if (xen_feature(XENFEAT_auto_translated_physmap))

		return;
@@ -2386,6 +2388,7 @@ void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order) 
	if (unlikely(order > MAX_CONTIG_ORDER))

		return;



	vstart = (unsigned long)phys_to_virt(pstart);

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



	spin_lock_irqsave(&xen_reservation_lock, flags);

drivers/xen/swiotlb-xen.c

+21 −10
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ 
#include <xen/xen-ops.h>

#include <xen/hvc-console.h>

#include <asm/dma-mapping.h>

#include <asm/xen/page-coherent.h>

/*

 * Used to do a quick range check in swiotlb_tbl_unmap_single and

 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
@@ -142,6 +143,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs) 
	int i, rc;

	int dma_bits;

	dma_addr_t dma_handle;

	phys_addr_t p = virt_to_phys(buf);



	dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
@@ -151,7 +153,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs) 


		do {

			rc = xen_create_contiguous_region(

				(unsigned long)buf + (i << IO_TLB_SHIFT),

				p + (i << IO_TLB_SHIFT),

				get_order(slabs << IO_TLB_SHIFT),

				dma_bits, &dma_handle);

		} while (rc && dma_bits++ < max_dma_bits);
@@ -279,7 +281,6 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, 
	void *ret;

	int order = get_order(size);

	u64 dma_mask = DMA_BIT_MASK(32);

	unsigned long vstart;

	phys_addr_t phys;

	dma_addr_t dev_addr;
@@ -294,8 +295,12 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, 
	if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret))

		return ret;



	vstart = __get_free_pages(flags, order);

	ret = (void *)vstart;

	/* On ARM this function returns an ioremap'ped virtual address for

	 * which virt_to_phys doesn't return the corresponding physical

	 * address. In fact on ARM virt_to_phys only works for kernel direct

	 * mapped RAM memory. Also see comment below.

	 */

	ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);



	if (!ret)

		return ret;
@@ -303,15 +308,19 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, 
	if (hwdev && hwdev->coherent_dma_mask)

		dma_mask = dma_alloc_coherent_mask(hwdev, flags);



	phys = virt_to_phys(ret);

	/* At this point dma_handle is the physical address, next we are

	 * going to set it to the machine address.

	 * Do not use virt_to_phys(ret) because on ARM it doesn't correspond

	 * to *dma_handle. */

	phys = *dma_handle;

	dev_addr = xen_phys_to_bus(phys);

	if (((dev_addr + size - 1 <= dma_mask)) &&

	    !range_straddles_page_boundary(phys, size))

		*dma_handle = dev_addr;

	else {

		if (xen_create_contiguous_region(vstart, order,

		if (xen_create_contiguous_region(phys, order,

						 fls64(dma_mask), dma_handle) != 0) {

			free_pages(vstart, order);

			xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);

			return NULL;

		}

	}
@@ -334,13 +343,15 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, 
	if (hwdev && hwdev->coherent_dma_mask)

		dma_mask = hwdev->coherent_dma_mask;



	phys = virt_to_phys(vaddr);

	/* do not use virt_to_phys because on ARM it doesn't return you the

	 * physical address */

	phys = xen_bus_to_phys(dev_addr);



	if (((dev_addr + size - 1 > dma_mask)) ||

	    range_straddles_page_boundary(phys, size))

		xen_destroy_contiguous_region((unsigned long)vaddr, order);

		xen_destroy_contiguous_region(phys, order);



	free_pages((unsigned long)vaddr, order);

	xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);

}

EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);

include/xen/xen-ops.h

+2 −2
Original line number Diff line number Diff line
@@ -19,11 +19,11 @@ void xen_arch_resume(void); 
int xen_setup_shutdown_event(void);



extern unsigned long *xen_contiguous_bitmap;

int xen_create_contiguous_region(unsigned long vstart, unsigned int order,

int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,

				unsigned int address_bits,

				dma_addr_t *dma_handle);



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

void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order);



struct vm_area_struct;

int xen_remap_domain_mfn_range(struct vm_area_struct *vma,