[Qemu-devel] [PATCH 6/8] Make sglists and dma_bdrv helpers use new universal DMA herlpers

[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>

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 dma-helpers.c  |   26 ++++++++++++++++++--------
 dma.h          |    3 ++-
 hw/ide/ahci.c  |    3 ++-
 hw/ide/macio.c |    4 ++--
 hw/pci.h       |    2 +-
 5 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/dma-helpers.c b/dma-helpers.c
index 57eb22c..c1759cd 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -11,12 +11,13 @@
 #include "block_int.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)
@@ -75,10 +76,9 @@ 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);
 }
@@ -104,10 +104,20 @@ static void dma_complete(DMAAIOCB *dbs, int ret)
     }
 }
 
+static void dma_bdrv_cancel(void *opaque)
+{
+    DMAAIOCB *dbs = opaque;
+
+    bdrv_aio_cancel(dbs->acb);
+    dma_bdrv_unmap(dbs);
+    qemu_iovec_destroy(&dbs->iov);
+    qemu_aio_release(dbs);
+}
+
 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);
@@ -124,8 +134,8 @@ 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, dma_bdrv_cancel, dbs,
+                             cur_addr, &cur_len, dbs->dir);
         if (!mem)
             break;
         qemu_iovec_add(&dbs->iov, mem, cur_len);
diff --git a/dma.h b/dma.h
index d7428df..b8cfd1d 100644
--- a/dma.h
+++ b/dma.h
@@ -125,9 +125,10 @@ struct QEMUSGList {
     int nsg;
     int nalloc;
     dma_addr_t size;
+    DMAContext *dma;
 };
 
-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 b515f41..aa05a48 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -716,7 +716,8 @@ 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 edcf885..568a299 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 64734a1..9d3f314 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -609,7 +609,7 @@ 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