[Qemu-devel] [PATCH 05/12] iommu: Make sglists and dma_bdrv helpers use new universal DMA helpers

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

From: David Gibson <david@gibson.dropbear.id.au>

dma-helpers.c contains a number of helper functions for doing
scatter/gather DMA, and various block device related DMA.  Currently,
these directly access guest memory using cpu_physical_memory_*(),
assuming no IOMMU translation.

This patch updates this code to use the new universal DMA helper
functions.  qemu_sglist_init() now takes a DMAContext * to describe
the DMA address space in which the scatter/gather will take place.

We minimally update the callers qemu_sglist_init() to pass NULL
(i.e. no translation, same as current behaviour).  Some of those
callers should pass something else in some cases to allow proper IOMMU
translation in future, but that will be fixed in later patches.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 dma-helpers.c  |   24 ++++++++++++------------
 dma.h          |    3 ++-
 hw/ide/ahci.c  |    3 ++-
 hw/ide/macio.c |    4 ++--
 hw/pci.h       |    2 +-
 5 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/dma-helpers.c b/dma-helpers.c
index 7971a89..2dc4691 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -10,12 +10,13 @@
 #include "dma.h"
 #include "trace.h"
 
-void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)
+void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint, DMAContext *dma)
 {
     qsg->sg = g_malloc(alloc_hint * sizeof(ScatterGatherEntry));
     qsg->nsg = 0;
     qsg->nalloc = alloc_hint;
     qsg->size = 0;
+    qsg->dma = dma;
 }
 
 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len)
@@ -74,10 +75,9 @@ static void dma_bdrv_unmap(DMAAIOCB *dbs)
     int i;
 
     for (i = 0; i < dbs->iov.niov; ++i) {
-        cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base,
-                                  dbs->iov.iov[i].iov_len,
-                                  dbs->dir != DMA_DIRECTION_TO_DEVICE,
-                                  dbs->iov.iov[i].iov_len);
+        dma_memory_unmap(dbs->sg->dma, dbs->iov.iov[i].iov_base,
+                         dbs->iov.iov[i].iov_len, dbs->dir,
+                         dbs->iov.iov[i].iov_len);
     }
     qemu_iovec_reset(&dbs->iov);
 }
@@ -106,7 +106,7 @@ static void dma_complete(DMAAIOCB *dbs, int ret)
 static void dma_bdrv_cb(void *opaque, int ret)
 {
     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
-    target_phys_addr_t cur_addr, cur_len;
+    dma_addr_t cur_addr, cur_len;
     void *mem;
 
     trace_dma_bdrv_cb(dbs, ret);
@@ -123,8 +123,7 @@ static void dma_bdrv_cb(void *opaque, int ret)
     while (dbs->sg_cur_index < dbs->sg->nsg) {
         cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
         cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
-        mem = cpu_physical_memory_map(cur_addr, &cur_len,
-                                      dbs->dir != DMA_DIRECTION_TO_DEVICE);
+        mem = dma_memory_map(dbs->sg->dma, cur_addr, &cur_len, dbs->dir);
         if (!mem)
             break;
         qemu_iovec_add(&dbs->iov, mem, cur_len);
@@ -209,7 +208,8 @@ BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
 }
 
 
-static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg, bool to_dev)
+static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg,
+                           DMADirection dir)
 {
     uint64_t resid;
     int sg_cur_index;
@@ -220,7 +220,7 @@ static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg, bool to_de
     while (len > 0) {
         ScatterGatherEntry entry = sg->sg[sg_cur_index++];
         int32_t xfer = MIN(len, entry.len);
-        cpu_physical_memory_rw(entry.base, ptr, xfer, !to_dev);
+        dma_memory_rw(sg->dma, entry.base, ptr, xfer, dir);
         ptr += xfer;
         len -= xfer;
         resid -= xfer;
@@ -231,12 +231,12 @@ static uint64_t dma_buf_rw(uint8_t *ptr, int32_t len, QEMUSGList *sg, bool to_de
 
 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 {
-    return dma_buf_rw(ptr, len, sg, 0);
+    return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_FROM_DEVICE);
 }
 
 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg)
 {
-    return dma_buf_rw(ptr, len, sg, 1);
+    return dma_buf_rw(ptr, len, sg, DMA_DIRECTION_TO_DEVICE);
 }
 
 void dma_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie,
diff --git a/dma.h b/dma.h
index 4449a0c..cd002c7 100644
--- a/dma.h
+++ b/dma.h
@@ -26,6 +26,7 @@ struct QEMUSGList {
     int nsg;
     int nalloc;
     size_t size;
+    DMAContext *dma;
 };
 
 #if defined(TARGET_PHYS_ADDR_BITS)
@@ -139,7 +140,7 @@ struct ScatterGatherEntry {
     dma_addr_t len;
 };
 
-void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint);
+void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint, DMAContext *dma);
 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
 void qemu_sglist_destroy(QEMUSGList *qsg);
 #endif
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index a883a92..96d8f62 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -667,7 +667,8 @@ static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist)
     if (sglist_alloc_hint > 0) {
         AHCI_SG *tbl = (AHCI_SG *)prdt;
 
-        qemu_sglist_init(sglist, sglist_alloc_hint);
+        /* FIXME: pass the correct DMAContext */
+        qemu_sglist_init(sglist, sglist_alloc_hint, NULL);
         for (i = 0; i < sglist_alloc_hint; i++) {
             /* flags_size is zero-based */
             qemu_sglist_add(sglist, le64_to_cpu(tbl[i].addr),
diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 7b38d9e..848cb31 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -76,7 +76,7 @@ static void pmac_ide_atapi_transfer_cb(void *opaque, int ret)
 
     s->io_buffer_size = io->len;
 
-    qemu_sglist_init(&s->sg, io->len / MACIO_PAGE_SIZE + 1);
+    qemu_sglist_init(&s->sg, io->len / MACIO_PAGE_SIZE + 1, NULL);
     qemu_sglist_add(&s->sg, io->addr, io->len);
     io->addr += io->len;
     io->len = 0;
@@ -133,7 +133,7 @@ static void pmac_ide_transfer_cb(void *opaque, int ret)
     s->io_buffer_index = 0;
     s->io_buffer_size = io->len;
 
-    qemu_sglist_init(&s->sg, io->len / MACIO_PAGE_SIZE + 1);
+    qemu_sglist_init(&s->sg, io->len / MACIO_PAGE_SIZE + 1, NULL);
     qemu_sglist_add(&s->sg, io->addr, io->len);
     io->addr += io->len;
     io->len = 0;
diff --git a/hw/pci.h b/hw/pci.h
index f2fe6bf..7e36c53 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -615,7 +615,7 @@ static inline void pci_dma_unmap(PCIDevice *dev, void *buffer, dma_addr_t len,
 static inline void pci_dma_sglist_init(QEMUSGList *qsg, PCIDevice *dev,
                                        int alloc_hint)
 {
-    qemu_sglist_init(qsg, alloc_hint);
+    qemu_sglist_init(qsg, alloc_hint, pci_dma_context(dev));
 }
 
 extern const VMStateDescription vmstate_pci_device;
-- 
1.7.9.5