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

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: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/arch/x86/include/asm/xen/swiotlb-xen.h b/arch/x86/include/asm/xen/swiotlb-xen.h
index 1be1ab7d6a4120d945aa22abf98a523f617196d8..ee52fcac6f72211ec3ac06e0e295193bc0e44817 100644 (file)
--- 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 1c1722761eecb9144ac0ffa8440e3362e233c09e..b152640d83884c2c4e80ca701bc158bb89eef726 100644 (file)
--- 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 = {
@@ -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,

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 701b1035fa6f4ea00fdcf99c995b35ec50d347de..7461edb5118eb2fabd60f8bfb3eafcb4a2acd960 100644 (file)
--- 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, 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.
         */
-       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_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 (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);
+       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 (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/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index 4f4d449f00f6b98644be40b85f108667c4cb1642..289ee509bda94b48ed53e3406d757ad21ffd095c 100644 (file)
--- 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,