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[Qemu-devel] Re: [PATCH 21/26] Implement TCE translation for sPAPR VIO


From: Alexander Graf
Subject: [Qemu-devel] Re: [PATCH 21/26] Implement TCE translation for sPAPR VIO
Date: Wed, 16 Mar 2011 17:03:54 +0100
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101206 SUSE/3.1.7 Thunderbird/3.1.7

On 03/16/2011 05:56 AM, David Gibson wrote:
From: Ben Herrenschmidt<address@hidden>

This patch implements the necessary infrastructure and hypercalls for
sPAPR's TCE (Translation Control Entry) IOMMU mechanism.  This is necessary
for all virtual IO devices which do DMA (i.e. nearly all of them).

Signed-off-by: Ben Herrenschmidt<address@hidden>
Signed-off-by: David Gibson<address@hidden>
---
  hw/spapr.c     |    3 +-
  hw/spapr_vio.c |  232 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  hw/spapr_vio.h |   32 ++++++++
  3 files changed, 266 insertions(+), 1 deletions(-)

diff --git a/hw/spapr.c b/hw/spapr.c
index e7f8864..a362889 100644
--- a/hw/spapr.c
+++ b/hw/spapr.c
@@ -62,7 +62,8 @@ static void *spapr_create_fdt(int *fdt_size, ram_addr_t 
ramsize,
      uint32_t start_prop = cpu_to_be32(initrd_base);
      uint32_t end_prop = cpu_to_be32(initrd_base + initrd_size);
      uint32_t pft_size_prop[] = {0, cpu_to_be32(hash_shift)};
-    char hypertas_prop[] = 
"hcall-pft\0hcall-term\0hcall-dabr\0hcall-interrupt";
+    char hypertas_prop[] = "hcall-pft\0hcall-term\0hcall-dabr\0hcall-interrupt"
+        "\0hcall-tce";
      uint32_t interrupt_server_ranges_prop[] = {0, cpu_to_be32(smp_cpus)};
      int i;
      char *modelname;
diff --git a/hw/spapr_vio.c b/hw/spapr_vio.c
index 45edd94..37cf51e 100644
--- a/hw/spapr_vio.c
+++ b/hw/spapr_vio.c
@@ -37,6 +37,7 @@
  #endif /* CONFIG_FDT */

  /* #define DEBUG_SPAPR */
+/* #define DEBUG_TCE */

  #ifdef DEBUG_SPAPR
  #define dprintf(fmt, ...) \
@@ -114,6 +115,28 @@ static int vio_make_devnode(VIOsPAPRDevice *dev,
              return ret;
      }

+    if (dev->rtce_window_size) {
+        uint32_t dma_prop[] = {cpu_to_be32(dev->reg),
+                               0, 0,
+                               0, cpu_to_be32(dev->rtce_window_size)};
+
+        ret = fdt_setprop_cell(fdt, node_off, "ibm,#dma-address-cells", 2);
+        if (ret<  0) {
+            return ret;
+        }
+
+        ret = fdt_setprop_cell(fdt, node_off, "ibm,#dma-size-cells", 2);
+        if (ret<  0) {
+            return ret;
+        }
+
+        ret = fdt_setprop(fdt, node_off, "ibm,my-dma-window", dma_prop,
+                          sizeof(dma_prop));
+        if (ret<  0) {
+            return ret;
+        }
+    }
+
      if (info->devnode) {
          ret = (info->devnode)(dev, fdt, node_off);
          if (ret<  0) {
@@ -125,6 +148,210 @@ static int vio_make_devnode(VIOsPAPRDevice *dev,
  }
  #endif /* CONFIG_FDT */

+/*
+ * RTCE handling
+ */
+
+static void rtce_init(VIOsPAPRDevice *dev)
+{
+    size_t size = (dev->rtce_window_size>>  SPAPR_VIO_TCE_PAGE_SHIFT)
+        * sizeof(VIOsPAPR_RTCE);
+
+    if (size) {
+        dev->rtce_table = qemu_mallocz(size);
+    }
+}
+
+static target_ulong h_put_tce(CPUState *env, sPAPREnvironment *spapr,
+                              target_ulong opcode, target_ulong *args)
+{
+    target_ulong liobn = args[0];
+    target_ulong ioba = args[1];
+    target_ulong tce = args[2];
+    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, liobn);
+    VIOsPAPR_RTCE *rtce;
+
+    if (!dev) {
+        fprintf(stderr, "spapr_vio_put_tce on non-existent LIOBN "
+                TARGET_FMT_lx "\n",
+                liobn);
+        return H_PARAMETER;
+    }
+
+    ioba&= ~(SPAPR_VIO_TCE_PAGE_SIZE - 1);
+
+#ifdef DEBUG_TCE
+    fprintf(stderr, "spapr_vio_put_tce on %s  ioba 0x" TARGET_FMT_lx
+            "  TCE 0x" TARGET_FMT_lx "\n", dev->qdev.id, ioba, tce);
+#endif
+
+    if (ioba>= dev->rtce_window_size) {
+        fprintf(stderr, "spapr_vio_put_tce on out-of-boards IOBA 0x" TARGET_FMT_lx 
"\n",
+                ioba);
+        return H_PARAMETER;
+    }
+
+    rtce = dev->rtce_table + (ioba>>  SPAPR_VIO_TCE_PAGE_SHIFT);
+    rtce->tce = tce;
+
+    return H_SUCCESS;
+}
+
+int spapr_vio_check_tces(VIOsPAPRDevice *dev, target_ulong ioba,
+                         target_ulong len, enum VIOsPAPR_TCEAccess access)
+{
+    int start, end, i;
+
+    start = ioba>>  SPAPR_VIO_TCE_PAGE_SHIFT;
+    end = (ioba + len - 1)>>  SPAPR_VIO_TCE_PAGE_SHIFT;
+
+    for (i = start; i<= end; i++) {
+        if ((dev->rtce_table[i].tce&  access) != access) {
+            fprintf(stderr, "FAIL on %d\n", i);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+/* XX Might want to special case KVM for speed ? */

XXX

+int spapr_tce_dma_write(VIOsPAPRDevice *dev, uint64_t taddr, const void *buf,
+                        uint32_t size)
+{
+#ifdef DEBUG_TCE
+    fprintf(stderr, "spapr_tce_dma_write taddr=0x%llx size=0x%x\n",
+            (unsigned long long)taddr, size);
+#endif
+
+    while(size) {
+        uint64_t tce;
+        uint32_t lsize;
+        uint64_t txaddr;
+
+        /* Check if we are in bound */
+        if (taddr>= dev->rtce_window_size) {
+            fprintf(stderr, "spapr_tce_dma_write out of bounds\n");
+            return -H_DEST_PARM;
+        }
+        tce = dev->rtce_table[taddr>>  SPAPR_VIO_TCE_PAGE_SHIFT].tce;
+
+        /* How much til end of page ? */
+        lsize = MIN(size, ((~taddr)&  SPAPR_VIO_TCE_PAGE_MASK) + 1);
+
+        /* Check TCE */
+        if (!(tce&  2))

Braces

+            return -H_DEST_PARM;
+
+        /* Translate */
+        txaddr = (tce&  ~SPAPR_VIO_TCE_PAGE_MASK) | (taddr&  
SPAPR_VIO_TCE_PAGE_MASK);
+
+#ifdef DEBUG_TCE
+        fprintf(stderr, " ->  write to txaddr=0x%llx, size=0x%x\n",
+                (unsigned long long)txaddr, lsize);
+#endif
+
+        /* Do it */
+        cpu_physical_memory_write(txaddr, buf, lsize);
+        buf += lsize;
+        taddr += lsize;
+        size -= lsize;
+    }
+    return 0;
+}
+
+/* XX Might want to special case KVM for speed ? */

XXX

+int spapr_tce_dma_zero(VIOsPAPRDevice *dev, uint64_t taddr, uint32_t size)
+{
+    uint8_t *zeroes;
+
+#ifdef DEBUG_TCE
+    fprintf(stderr, "spapr_tce_dma_zero taddr=0x%llx size=0x%x\n",
+            (unsigned long long)taddr, size);
+#endif
+
+    /* FIXME: do this better... */
+    zeroes = alloca(size);
+    memset(zeroes, 0, size);

You sure that zeroes is still alive during the call? If I were a compiler, I'd probably optimize the return away so that it'd end up being a simple branch to spapr_tce_dma_write - coincidentally invalidating the stack that zeroes is on.


Alex




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