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[PATCH 13/15] swiotlb: merge swiotlb-xen initialization into swiotlb



Reuse the generic swiotlb initialization for xen-swiotlb.  For ARM/ARM64
this works trivially, while for x86 xen_swiotlb_fixup needs to be passed
as the remap argument to swiotlb_init_remap/swiotlb_init_late.

Note that the lower bound of the swiotlb size is changed to the smaller
IO_TLB_MIN_SLABS based value with this patch, but that is fine as the
2MB value used in Xen before was just an optimization and is not the
hard lower bound.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 arch/arm/xen/mm.c               |  21 +++---
 arch/x86/include/asm/xen/page.h |   5 --
 arch/x86/kernel/pci-dma.c       |  20 ++---
 drivers/xen/swiotlb-xen.c       | 128 +-------------------------------
 include/xen/arm/page.h          |   1 -
 include/xen/swiotlb-xen.h       |   8 +-
 6 files changed, 28 insertions(+), 155 deletions(-)

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 28c2070602535..ff05a7899cb86 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -23,22 +23,20 @@
 #include <asm/xen/hypercall.h>
 #include <asm/xen/interface.h>
 
-unsigned long xen_get_swiotlb_free_pages(unsigned int order)
+static gfp_t xen_swiotlb_gfp(void)
 {
        phys_addr_t base;
-       gfp_t flags = __GFP_NOWARN|__GFP_KSWAPD_RECLAIM;
        u64 i;
 
        for_each_mem_range(i, &base, NULL) {
                if (base < (phys_addr_t)0xffffffff) {
                        if (IS_ENABLED(CONFIG_ZONE_DMA32))
-                               flags |= __GFP_DMA32;
-                       else
-                               flags |= __GFP_DMA;
-                       break;
+                               return __GFP_DMA32;
+                       return __GFP_DMA;
                }
        }
-       return __get_free_pages(flags, order);
+
+       return GFP_KERNEL;
 }
 
 static bool hypercall_cflush = false;
@@ -140,10 +138,13 @@ static int __init xen_mm_init(void)
        if (!xen_swiotlb_detect())
                return 0;
 
-       rc = xen_swiotlb_init();
        /* we can work with the default swiotlb */
-       if (rc < 0 && rc != -EEXIST)
-               return rc;
+       if (!io_tlb_default_mem.nslabs) {
+               rc = swiotlb_init_late(swiotlb_size_or_default(),
+                                      xen_swiotlb_gfp(), NULL);
+               if (rc < 0)
+                       return rc;
+       }
 
        cflush.op = 0;
        cflush.a.dev_bus_addr = 0;
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index e989bc2269f54..1fc67df500145 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -357,9 +357,4 @@ static inline bool xen_arch_need_swiotlb(struct device *dev,
        return false;
 }
 
-static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order)
-{
-       return __get_free_pages(__GFP_NOWARN, order);
-}
-
 #endif /* _ASM_X86_XEN_PAGE_H */
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index a705a199bf8a3..30bbe4abb5d61 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -72,15 +72,13 @@ static inline void __init pci_swiotlb_detect(void)
 #endif /* CONFIG_SWIOTLB */
 
 #ifdef CONFIG_SWIOTLB_XEN
-static bool xen_swiotlb;
-
 static void __init pci_xen_swiotlb_init(void)
 {
        if (!xen_initial_domain() && !x86_swiotlb_enable)
                return;
        x86_swiotlb_enable = true;
-       xen_swiotlb = true;
-       xen_swiotlb_init_early();
+       x86_swiotlb_flags |= SWIOTLB_ANY;
+       swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);
        dma_ops = &xen_swiotlb_dma_ops;
        if (IS_ENABLED(CONFIG_PCI))
                pci_request_acs();
@@ -88,14 +86,16 @@ static void __init pci_xen_swiotlb_init(void)
 
 int pci_xen_swiotlb_init_late(void)
 {
-       int rc;
-
-       if (xen_swiotlb)
+       if (dma_ops == &xen_swiotlb_dma_ops)
                return 0;
 
-       rc = xen_swiotlb_init();
-       if (rc)
-               return rc;
+       /* we can work with the default swiotlb */
+       if (!io_tlb_default_mem.nslabs) {
+               int rc = swiotlb_init_late(swiotlb_size_or_default(),
+                                          GFP_KERNEL, xen_swiotlb_fixup);
+               if (rc < 0)
+                       return rc;
+       }
 
        /* XXX: this switches the dma ops under live devices! */
        dma_ops = &xen_swiotlb_dma_ops;
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index c2da3eb4826e8..df8085b50df10 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -104,7 +104,7 @@ static int is_xen_swiotlb_buffer(struct device *dev, 
dma_addr_t dma_addr)
        return 0;
 }
 
-static int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
+int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
 {
        int rc;
        unsigned int order = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT);
@@ -130,132 +130,6 @@ static int xen_swiotlb_fixup(void *buf, unsigned long 
nslabs)
        return 0;
 }
 
-enum xen_swiotlb_err {
-       XEN_SWIOTLB_UNKNOWN = 0,
-       XEN_SWIOTLB_ENOMEM,
-       XEN_SWIOTLB_EFIXUP
-};
-
-static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
-{
-       switch (err) {
-       case XEN_SWIOTLB_ENOMEM:
-               return "Cannot allocate Xen-SWIOTLB buffer\n";
-       case XEN_SWIOTLB_EFIXUP:
-               return "Failed to get contiguous memory for DMA from Xen!\n"\
-                   "You either: don't have the permissions, do not have"\
-                   " enough free memory under 4GB, or the hypervisor memory"\
-                   " is too fragmented!";
-       default:
-               break;
-       }
-       return "";
-}
-
-int xen_swiotlb_init(void)
-{
-       enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
-       unsigned long bytes = swiotlb_size_or_default();
-       unsigned long nslabs = bytes >> IO_TLB_SHIFT;
-       unsigned int order, repeat = 3;
-       int rc = -ENOMEM;
-       char *start;
-
-       if (io_tlb_default_mem.nslabs) {
-               pr_warn("swiotlb buffer already initialized\n");
-               return -EEXIST;
-       }
-
-retry:
-       m_ret = XEN_SWIOTLB_ENOMEM;
-       order = get_order(bytes);
-
-       /*
-        * Get IO TLB memory from any location.
-        */
-#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) {
-               start = (void *)xen_get_swiotlb_free_pages(order);
-               if (start)
-                       break;
-               order--;
-       }
-       if (!start)
-               goto exit;
-       if (order != get_order(bytes)) {
-               pr_warn("Warning: only able to allocate %ld MB for software IO 
TLB\n",
-                       (PAGE_SIZE << order) >> 20);
-               nslabs = SLABS_PER_PAGE << order;
-               bytes = nslabs << IO_TLB_SHIFT;
-       }
-
-       /*
-        * And replace that memory with pages under 4GB.
-        */
-       rc = xen_swiotlb_fixup(start, nslabs);
-       if (rc) {
-               free_pages((unsigned long)start, order);
-               m_ret = XEN_SWIOTLB_EFIXUP;
-               goto error;
-       }
-       rc = swiotlb_late_init_with_tbl(start, nslabs);
-       if (rc)
-               return rc;
-       return 0;
-error:
-       if (nslabs > 1024 && repeat--) {
-               /* Min is 2MB */
-               nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
-               bytes = nslabs << IO_TLB_SHIFT;
-               pr_info("Lowering to %luMB\n", bytes >> 20);
-               goto retry;
-       }
-exit:
-       pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
-       return rc;
-}
-
-#ifdef CONFIG_X86
-void __init xen_swiotlb_init_early(void)
-{
-       unsigned long bytes = swiotlb_size_or_default();
-       unsigned long nslabs = bytes >> IO_TLB_SHIFT;
-       unsigned int repeat = 3;
-       char *start;
-       int rc;
-
-retry:
-       /*
-        * Get IO TLB memory from any location.
-        */
-       start = memblock_alloc(PAGE_ALIGN(bytes),
-                              IO_TLB_SEGSIZE << IO_TLB_SHIFT);
-       if (!start)
-               panic("%s: Failed to allocate %lu bytes\n",
-                     __func__, PAGE_ALIGN(bytes));
-
-       /*
-        * And replace that memory with pages under 4GB.
-        */
-       rc = xen_swiotlb_fixup(start, nslabs);
-       if (rc) {
-               memblock_free(start, PAGE_ALIGN(bytes));
-               if (nslabs > 1024 && repeat--) {
-                       /* Min is 2MB */
-                       nslabs = max(1024UL, ALIGN(nslabs >> 1, 
IO_TLB_SEGSIZE));
-                       bytes = nslabs << IO_TLB_SHIFT;
-                       pr_info("Lowering to %luMB\n", bytes >> 20);
-                       goto retry;
-               }
-               panic("%s (rc:%d)", xen_swiotlb_error(XEN_SWIOTLB_EFIXUP), rc);
-       }
-
-       if (swiotlb_init_with_tbl(start, nslabs, SWIOTLB_VERBOSE))
-               panic("Cannot allocate SWIOTLB buffer");
-}
-#endif /* CONFIG_X86 */
-
 static void *
 xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                           dma_addr_t *dma_handle, gfp_t flags,
diff --git a/include/xen/arm/page.h b/include/xen/arm/page.h
index ac1b654705631..7e199c6656b90 100644
--- a/include/xen/arm/page.h
+++ b/include/xen/arm/page.h
@@ -115,6 +115,5 @@ static inline bool set_phys_to_machine(unsigned long pfn, 
unsigned long mfn)
 bool xen_arch_need_swiotlb(struct device *dev,
                           phys_addr_t phys,
                           dma_addr_t dev_addr);
-unsigned long xen_get_swiotlb_free_pages(unsigned int order);
 
 #endif /* _ASM_ARM_XEN_PAGE_H */
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index b3e647f86e3e2..590ceb923f0c8 100644
--- a/include/xen/swiotlb-xen.h
+++ b/include/xen/swiotlb-xen.h
@@ -10,8 +10,12 @@ void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t 
handle,
 void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle,
                             size_t size, enum dma_data_direction dir);
 
-int xen_swiotlb_init(void);
-void __init xen_swiotlb_init_early(void);
+#ifdef CONFIG_SWIOTLB_XEN
+int xen_swiotlb_fixup(void *buf, unsigned long nslabs);
+#else
+#define xen_swiotlb_fixup NULL
+#endif
+
 extern const struct dma_map_ops xen_swiotlb_dma_ops;
 
 #endif /* __LINUX_SWIOTLB_XEN_H */
-- 
2.30.2




 


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