7 files changed, 154 insertions, 45 deletions

diff --git a/arch/x86/include/asm/xen/swiotlb-xen.h b/arch/x86/include/asm/xen/swiotlb-xen.h
index 1be1ab7d6a41..ee52fcac6f72 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 1ab45941502d..969570491c39 100644
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ b/arch/x86/xen/pci-swiotlb-xen.c
@@ -8,7 +8,14 @@
 #include <xen/xen.h>
 #include <asm/iommu_table.h>
 
+
 #include <asm/xen/swiotlb-xen.h>
+#ifdef CONFIG_X86_64
+#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 = {
@@ -35,33 +42,63 @@ static struct dma_map_ops xen_swiotlb_dma_ops = {
 int __init pci_xen_swiotlb_detect(void)
 {
 
+        if (!xen_pv_domain())
+                return 0;
+
         /* If running as PV guest, either iommu=soft, or swiotlb=force will
          * activate this IOMMU. If running as PV privileged, activate it
          * irregardless.
          */
-        if ((xen_initial_domain() || swiotlb || swiotlb_force) &&
-            (xen_pv_domain()))
+        if ((xen_initial_domain() || swiotlb || swiotlb_force))
                 xen_swiotlb = 1;
 
         /* If we are running under Xen, we MUST disable the native SWIOTLB.
          * Don't worry about swiotlb_force flag activating the native, as
          * the 'swiotlb' flag is the only one turning it on. */
-        if (xen_pv_domain())
-                swiotlb = 0;
+        swiotlb = 0;
 
+#ifdef CONFIG_X86_64
+        /* pci_swiotlb_detect_4gb turns on native SWIOTLB if no_iommu == 0
+         * (so no iommu=X command line over-writes).
+         * Considering that PV guests do not want the *native SWIOTLB* but
+         * only Xen SWIOTLB it is not useful to us so set no_iommu=1 here.
+         */
+        if (max_pfn > MAX_DMA32_PFN)
+                no_iommu = 1;
+#endif
         return xen_swiotlb;
 }
 
 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,
                   NULL,
                   pci_xen_swiotlb_init,
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index a4d901def8f2..7d6773535b67 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -21,6 +21,7 @@
 #include <linux/bitops.h>
 #include <linux/time.h>
 
+#include <asm/xen/swiotlb-xen.h>
 #define INVALID_GRANT_REF (0)
 #define INVALID_EVTCHN    (-1)
 
@@ -668,7 +669,7 @@ static irqreturn_t pcifront_handler_aer(int irq, void *dev)
         schedule_pcifront_aer_op(pdev);
         return IRQ_HANDLED;
 }
-static int pcifront_connect(struct pcifront_device *pdev)
+static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
 {
         int err = 0;
 
@@ -681,9 +682,13 @@ static int pcifront_connect(struct pcifront_device *pdev)
                 dev_err(&pdev->xdev->dev, "PCI frontend already installed!\n");
                 err = -EEXIST;
         }
-
         spin_unlock(&pcifront_dev_lock);
 
+        if (!err && !swiotlb_nr_tbl()) {
+                err = pci_xen_swiotlb_init_late();
+                if (err)
+                        dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
+        }
         return err;
 }
 
@@ -842,10 +847,10 @@ static int __devinit pcifront_try_connect(struct pcifront_device *pdev)
             XenbusStateInitialised)
                 goto out;
 
-        err = pcifront_connect(pdev);
+        err = pcifront_connect_and_init_dma(pdev);
         if (err) {
                 xenbus_dev_fatal(pdev->xdev, err,
-                                 "Error connecting PCI Frontend");
+                                 "Error setting up PCI Frontend");
                 goto out;
         }
 
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 2e74dba6a04d..58db6df866ef 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -144,31 +144,72 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
         } while (i < nslabs);
         return 0;
 }
+static unsigned long xen_set_nslabs(unsigned long nr_tbl)
+{
+        if (!nr_tbl) {
+                xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
+                xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
+        } else
+                xen_io_tlb_nslabs = nr_tbl;
+
+        return xen_io_tlb_nslabs << IO_TLB_SHIFT;
+}
+
+enum xen_swiotlb_err {
+        XEN_SWIOTLB_UNKNOWN = 0,
+        XEN_SWIOTLB_ENOMEM,
+        XEN_SWIOTLB_EFIXUP
+};
 
-void __init xen_swiotlb_init(int verbose)
+static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
 {
-        unsigned long bytes;
+        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 __ref xen_swiotlb_init(int verbose, bool early)
+{
+        unsigned long bytes, order;
         int rc = -ENOMEM;
-        unsigned long nr_tbl;
-        char *m = NULL;
+        enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
         unsigned int repeat = 3;
 
-        nr_tbl = swiotlb_nr_tbl();
-        if (nr_tbl)
-                xen_io_tlb_nslabs = nr_tbl;
-        else {
-                xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
-                xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
-        }
+        xen_io_tlb_nslabs = swiotlb_nr_tbl();
 retry:
-        bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
-
+        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 (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 = "Cannot allocate Xen-SWIOTLB buffer!\n";
+                m_ret = XEN_SWIOTLB_ENOMEM;
                 goto error;
         }
         xen_io_tlb_end = xen_io_tlb_start + bytes;
@@ -179,17 +220,22 @@ retry:
                                bytes,
                                xen_io_tlb_nslabs);
         if (rc) {
-                free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
-                m = "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!";
+                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);
-        swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
-
-        return;
+        if (early) {
+                swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
+                rc = 0;
+        } 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 */
@@ -198,10 +244,13 @@ error:
                       (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
                 goto retry;
         }
-        xen_raw_printk("%s (rc:%d)", m, rc);
-        panic("%s (rc:%d)", m, 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,
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index e872526fdc5f..8d08b3ed406d 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -25,6 +25,7 @@ extern int swiotlb_force;
 extern void swiotlb_init(int verbose);
 extern void swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
 extern unsigned long swiotlb_nr_tbl(void);
+extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
 
 /*
  * Enumeration for sync targets
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index c050b6b9de38..de8bcc641c49 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, bool early);
 
 extern void
 *xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 45bc1f83a5ad..f114bf6a8e13 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -170,7 +170,7 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
  * Statically reserve bounce buffer space and initialize bounce buffer data
  * structures for the software IO TLB used to implement the DMA API.
  */
-void __init
+static void __init
 swiotlb_init_with_default_size(size_t default_size, int verbose)
 {
         unsigned long bytes;
@@ -206,8 +206,9 @@ swiotlb_init(int verbose)
 int
 swiotlb_late_init_with_default_size(size_t default_size)
 {
-        unsigned long i, bytes, req_nslabs = io_tlb_nslabs;
+        unsigned long bytes, req_nslabs = io_tlb_nslabs;
         unsigned int order;
+        int rc = 0;
 
         if (!io_tlb_nslabs) {
                 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
@@ -229,16 +230,32 @@ swiotlb_late_init_with_default_size(size_t default_size)
                 order--;
         }
 
-        if (!io_tlb_start)
-                goto cleanup1;
-
+        if (!io_tlb_start) {
+                io_tlb_nslabs = req_nslabs;
+                return -ENOMEM;
+        }
         if (order != get_order(bytes)) {
                 printk(KERN_WARNING "Warning: only able to allocate %ld MB "
                        "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
                 io_tlb_nslabs = SLABS_PER_PAGE << order;
-                bytes = io_tlb_nslabs << IO_TLB_SHIFT;
         }
+        rc = swiotlb_late_init_with_tbl(io_tlb_start, io_tlb_nslabs);
+        if (rc)
+                free_pages((unsigned long)io_tlb_start, order);
+        return rc;
+}
+
+int
+swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
+{
+        unsigned long i, bytes;
+
+        bytes = nslabs << IO_TLB_SHIFT;
+
+        io_tlb_nslabs = nslabs;
+        io_tlb_start = tlb;
         io_tlb_end = io_tlb_start + bytes;
+
         memset(io_tlb_start, 0, bytes);
 
         /*
@@ -288,10 +305,8 @@ cleanup3:
         io_tlb_list = NULL;
 cleanup2:
         io_tlb_end = NULL;
-        free_pages((unsigned long)io_tlb_start, order);
         io_tlb_start = NULL;
-cleanup1:
-        io_tlb_nslabs = req_nslabs;
+        io_tlb_nslabs = 0;
         return -ENOMEM;
 }