On 03/07/2016 05:05 PM, David Gibson wrote:
On Mon, Mar 07, 2016 at 02:41:12PM +1100, Alexey Kardashevskiy wrote:
In real mode, TCE tables are invalidated using different
cache-inhibited store instructions which is different from
the virtual mode.

This defines and implements exchange_rm() callback. This does not
define set_rm/clear_rm/flush_rm callbacks as there is no user for those -
exchange/exchange_rm are only to be used by KVM for VFIO.

The exchange_rm callback is defined for IODA1/IODA2 powernv platforms.

This replaces list_for_each_entry_rcu with its lockless version as
from now on pnv_pci_ioda2_tce_invalidate() can be called in
the real mode too.

Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
  arch/powerpc/include/asm/iommu.h          |  7 +++++++
  arch/powerpc/kernel/iommu.c               | 15 +++++++++++++++
  arch/powerpc/platforms/powernv/pci-ioda.c | 28 +++++++++++++++++++++++++++-
  3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 7b87bab..3ca877a 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -64,6 +64,11 @@ struct iommu_table_ops {
                        long index,
                        unsigned long *hpa,
                        enum dma_data_direction *direction);
+       /* Real mode */
+       int (*exchange_rm)(struct iommu_table *tbl,
+                       long index,
+                       unsigned long *hpa,
+                       enum dma_data_direction *direction);
  #endif
        void (*clear)(struct iommu_table *tbl,
                        long index, long npages);
@@ -208,6 +213,8 @@ extern void iommu_del_device(struct device *dev);
  extern int __init tce_iommu_bus_notifier_init(void);
  extern long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
                unsigned long *hpa, enum dma_data_direction *direction);
+extern long iommu_tce_xchg_rm(struct iommu_table *tbl, unsigned long entry,
+               unsigned long *hpa, enum dma_data_direction *direction);
  #else
  static inline void iommu_register_group(struct iommu_table_group *table_group,
                                        int pci_domain_number,
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index a8e3490..2fcc48b 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1062,6 +1062,21 @@ void iommu_release_ownership(struct iommu_table *tbl)
  }
  EXPORT_SYMBOL_GPL(iommu_release_ownership);

+long iommu_tce_xchg_rm(struct iommu_table *tbl, unsigned long entry,
+               unsigned long *hpa, enum dma_data_direction *direction)
+{
+       long ret;
+
+       ret = tbl->it_ops->exchange_rm(tbl, entry, hpa, direction);
+
+       if (!ret && ((*direction == DMA_FROM_DEVICE) ||
+                       (*direction == DMA_BIDIRECTIONAL)))
+               SetPageDirty(realmode_pfn_to_page(*hpa >> PAGE_SHIFT));
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_tce_xchg_rm);

  int iommu_add_device(struct device *dev)
  {
        struct iommu_table *tbl;
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c 
b/arch/powerpc/platforms/powernv/pci-ioda.c
index c5baaf3..bed1944 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1791,6 +1791,18 @@ static int pnv_ioda1_tce_xchg(struct iommu_table *tbl, 
long index,

        return ret;
  }
+
+static int pnv_ioda1_tce_xchg_rm(struct iommu_table *tbl, long index,
+               unsigned long *hpa, enum dma_data_direction *direction)
+{
+       long ret = pnv_tce_xchg(tbl, index, hpa, direction);
+
+       if (!ret && (tbl->it_type &
+                       (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE)))
+               pnv_pci_ioda1_tce_invalidate(tbl, index, 1, true);
+
+       return ret;
+}
  #endif

Both your _rm variants are identical to the non _rm versions.  Why not
just set the function poiinter to the same thing, rather than copying
the whole function.


The last parameter - "rm" - to pnv_pci_ioda1_tce_invalidate() is different.



  static void pnv_ioda1_tce_free(struct iommu_table *tbl, long index,
@@ -1806,6 +1818,7 @@ static struct iommu_table_ops pnv_ioda1_iommu_ops = {
        .set = pnv_ioda1_tce_build,
  #ifdef CONFIG_IOMMU_API
        .exchange = pnv_ioda1_tce_xchg,
+       .exchange_rm = pnv_ioda1_tce_xchg_rm,
  #endif
        .clear = pnv_ioda1_tce_free,
        .get = pnv_tce_get,
@@ -1866,7 +1879,7 @@ static void pnv_pci_ioda2_tce_invalidate(struct 
iommu_table *tbl,
  {
        struct iommu_table_group_link *tgl;

-       list_for_each_entry_rcu(tgl, &tbl->it_group_list, next) {
+       list_for_each_entry_lockless(tgl, &tbl->it_group_list, next) {
                struct pnv_ioda_pe *npe;
                struct pnv_ioda_pe *pe = container_of(tgl->table_group,
                                struct pnv_ioda_pe, table_group);
@@ -1918,6 +1931,18 @@ static int pnv_ioda2_tce_xchg(struct iommu_table *tbl, 
long index,

        return ret;
  }
+
+static int pnv_ioda2_tce_xchg_rm(struct iommu_table *tbl, long index,
+               unsigned long *hpa, enum dma_data_direction *direction)
+{
+       long ret = pnv_tce_xchg(tbl, index, hpa, direction);
+
+       if (!ret && (tbl->it_type &
+                       (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE)))
+               pnv_pci_ioda2_tce_invalidate(tbl, index, 1, true);
+
+       return ret;
+}
  #endif

  static void pnv_ioda2_tce_free(struct iommu_table *tbl, long index,
@@ -1939,6 +1964,7 @@ static struct iommu_table_ops pnv_ioda2_iommu_ops = {
        .set = pnv_ioda2_tce_build,
  #ifdef CONFIG_IOMMU_API
        .exchange = pnv_ioda2_tce_xchg,
+       .exchange_rm = pnv_ioda2_tce_xchg_rm,
  #endif
        .clear = pnv_ioda2_tce_free,
        .get = pnv_tce_get,



--
Alexey
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