Commit b8277600 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen/swiotlb: Use the swiotlb_late_init_with_tbl to init Xen-SWIOTLB late when PV PCI is used. 



With this patch we provide the functionality to initialize the
Xen-SWIOTLB late in the bootup cycle - specifically for
Xen PCI-frontend. We still will work if the user had
supplied 'iommu=soft' on the Linux command line.

Note: We cannot depend on after_bootmem to automatically
determine whether this is early or not. This is because
when PCI IOMMUs are initialized it is after after_bootmem but
before a lot of "other" subsystems are initialized.

CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
[v1: Fix smatch warnings]
[v2: Added check for xen_swiotlb]
[v3: Rebased with new xen-swiotlb changes]
[v4: squashed xen/swiotlb: Depending on after_bootmem is not correct in]
Reviewed-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 5bab7864

arch/x86/include/asm/xen/swiotlb-xen.h

+2 −0
Original line number Diff line number Diff line
@@ -5,10 +5,12 @@ 
extern int xen_swiotlb;

extern int __init pci_xen_swiotlb_detect(void);

extern void __init pci_xen_swiotlb_init(void);

extern int pci_xen_swiotlb_init_late(void);

#else

#define xen_swiotlb (0)

static inline int __init pci_xen_swiotlb_detect(void) { return 0; }

static inline void __init pci_xen_swiotlb_init(void) { }

static inline int pci_xen_swiotlb_init_late(void) { return -ENXIO; }

#endif



#endif /* _ASM_X86_SWIOTLB_XEN_H */

arch/x86/xen/pci-swiotlb-xen.c

+22 −2
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ 
#include <asm/iommu.h>

#include <asm/dma.h>

#endif



#include <linux/export.h>

int xen_swiotlb __read_mostly;



static struct dma_map_ops xen_swiotlb_dma_ops = {
@@ -69,13 +69,33 @@ int __init pci_xen_swiotlb_detect(void) 
void __init pci_xen_swiotlb_init(void)

{

	if (xen_swiotlb) {

		xen_swiotlb_init(1);

		xen_swiotlb_init(1, true /* early */);

		dma_ops = &xen_swiotlb_dma_ops;



		/* Make sure ACS will be enabled */

		pci_request_acs();

	}

}



int pci_xen_swiotlb_init_late(void)

{

	int rc;



	if (xen_swiotlb)

		return 0;



	rc = xen_swiotlb_init(1, false /* late */);

	if (rc)

		return rc;



	dma_ops = &xen_swiotlb_dma_ops;

	/* Make sure ACS will be enabled */

	pci_request_acs();



	return 0;

}

EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);



IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,

		  0,

		  pci_xen_swiotlb_init,

drivers/xen/swiotlb-xen.c

+38 −10
Original line number Diff line number Diff line
@@ -176,9 +176,9 @@ static const char *xen_swiotlb_error(enum xen_swiotlb_err err) 
	}

	return "";

}

void __init xen_swiotlb_init(int verbose)

int __ref xen_swiotlb_init(int verbose, bool early)

{

	unsigned long bytes;

	unsigned long bytes, order;

	int rc = -ENOMEM;

	enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;

	unsigned int repeat = 3;
@@ -186,10 +186,28 @@ void __init xen_swiotlb_init(int verbose) 
	xen_io_tlb_nslabs = swiotlb_nr_tbl();

retry:

	bytes = xen_set_nslabs(xen_io_tlb_nslabs);

	order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);

	/*

	 * Get IO TLB memory from any location.

	 */

	if (early)

		xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));

	else {

#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))

#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)

		while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {

			xen_io_tlb_start = (void *)__get_free_pages(__GFP_NOWARN, order);

			if (xen_io_tlb_start)

				break;

			order--;

		}

		if (order != get_order(bytes)) {

			pr_warn("Warning: only able to allocate %ld MB "

				"for software IO TLB\n", (PAGE_SIZE << order) >> 20);

			xen_io_tlb_nslabs = SLABS_PER_PAGE << order;

			bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;

		}

	}

	if (!xen_io_tlb_start) {

		m_ret = XEN_SWIOTLB_ENOMEM;

		goto error;
@@ -202,14 +220,21 @@ retry: 
			       bytes,

			       xen_io_tlb_nslabs);

	if (rc) {

		if (early)

			free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));

		else {

			free_pages((unsigned long)xen_io_tlb_start, order);

			xen_io_tlb_start = NULL;

		}

		m_ret = XEN_SWIOTLB_EFIXUP;

		goto error;

	}

	start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);

	if (early)

		swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);



	return;

	else

		rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);

	return rc;

error:

	if (repeat--) {

		xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
@@ -218,10 +243,13 @@ error: 
		      (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);

		goto retry;

	}

	xen_raw_printk("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);

	pr_err("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);

	if (early)

		panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);

	else

		free_pages((unsigned long)xen_io_tlb_start, order);

	return rc;

}



void *

xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,

			   dma_addr_t *dma_handle, gfp_t flags,

include/xen/swiotlb-xen.h

+1 −1
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ 


#include <linux/swiotlb.h>



extern void xen_swiotlb_init(int verbose);

extern int xen_swiotlb_init(int verbose, bool early);



extern void

*xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,

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