Re: [PATCH 06/10] xen/swiotlb: Use the swiotlb_late_init_with_tblto init Xen-SWIOTLB late when PV PCI is used.

From: Stefano Stabellini
Date: Fri Sep 14 2012 - 12:27:02 EST

On Mon, 10 Sep 2012, Konrad Rzeszutek Wilk wrote:
> 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.
>
> CC: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
> [v1: Fix smatch warnings]
> [v2: Added check for xen_swiotlb]
> [v3: Rebased with new xen-swiotlb changes]
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>


> arch/x86/include/asm/xen/swiotlb-xen.h | 2 +
> arch/x86/xen/pci-swiotlb-xen.c | 22 ++++++++++++++-
> drivers/xen/swiotlb-xen.c | 48 +++++++++++++++++++++++++------
> include/xen/swiotlb-xen.h | 2 +-
> 4 files changed, 62 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/include/asm/xen/swiotlb-xen.h b/arch/x86/include/asm/xen/swiotlb-xen.h
> index 1be1ab7..ee52fca 100644
> --- a/arch/x86/include/asm/xen/swiotlb-xen.h
> +++ b/arch/x86/include/asm/xen/swiotlb-xen.h
> @@ -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 */
> diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
> index 1c17227..406f9c4 100644
> --- a/arch/x86/xen/pci-swiotlb-xen.c
> +++ b/arch/x86/xen/pci-swiotlb-xen.c
> @@ -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 = {
> @@ -76,6 +76,26 @@ void __init pci_xen_swiotlb_init(void)
> pci_request_acs();
> }
> }
> +
> +int pci_xen_swiotlb_init_late(void)
> +{
> + int rc;
> +
> + if (xen_swiotlb)
> + return 0;
> +
> + rc = xen_swiotlb_init(1);
> + 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,
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 701b103..f0825cb 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -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)
> {
> - 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.
> */
> - xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
> + if (!after_bootmem)
> + 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) {
> - free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
> + if (!after_bootmem)
> + 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);
> - swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
> -
> - return;
> + if (!after_bootmem)
> + swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
> + 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);
> - panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
> + pr_err("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
> + if (!after_bootmem)
> + 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,
> diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
> index 4f4d449..f26f9f3 100644
> --- a/include/xen/swiotlb-xen.h
> +++ b/include/xen/swiotlb-xen.h
> @@ -3,7 +3,7 @@
>
> #include <linux/swiotlb.h>
>
> -extern void xen_swiotlb_init(int verbose);
> +extern int xen_swiotlb_init(int verbose);
>
> extern void
> *xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
> --
> 1.7.7.6
>
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