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[Qemu-devel] [6394] Add target memory mapping API (Avi Kivity)
From: |
Anthony Liguori |
Subject: |
[Qemu-devel] [6394] Add target memory mapping API (Avi Kivity) |
Date: |
Thu, 22 Jan 2009 16:59:12 +0000 |
Revision: 6394
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6394
Author: aliguori
Date: 2009-01-22 16:59:11 +0000 (Thu, 22 Jan 2009)
Log Message:
-----------
Add target memory mapping API (Avi Kivity)
Devices accessing large amounts of memory (as with DMA) will wish to obtain
a pointer to guest memory rather than access it indirectly via
cpu_physical_memory_rw(). Add a new API to convert target addresses to
host pointers.
In case the target address does not correspond to RAM, a bounce buffer is
allocated. To prevent the guest from causing the host to allocate unbounded
amounts of bounce buffer, this memory is limited (currently to one page).
Signed-off-by: Avi Kivity <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
Modified Paths:
--------------
trunk/cpu-all.h
trunk/exec.c
Modified: trunk/cpu-all.h
===================================================================
--- trunk/cpu-all.h 2009-01-22 16:18:33 UTC (rev 6393)
+++ trunk/cpu-all.h 2009-01-22 16:59:11 UTC (rev 6394)
@@ -923,6 +923,12 @@
{
cpu_physical_memory_rw(addr, (uint8_t *)buf, len, 1);
}
+void *cpu_physical_memory_map(target_phys_addr_t addr,
+ target_phys_addr_t *plen,
+ int is_write);
+void cpu_physical_memory_unmap(void *buffer, target_phys_addr_t len,
+ int is_write, target_phys_addr_t access_len);
+
uint32_t ldub_phys(target_phys_addr_t addr);
uint32_t lduw_phys(target_phys_addr_t addr);
uint32_t ldl_phys(target_phys_addr_t addr);
Modified: trunk/exec.c
===================================================================
--- trunk/exec.c 2009-01-22 16:18:33 UTC (rev 6393)
+++ trunk/exec.c 2009-01-22 16:59:11 UTC (rev 6394)
@@ -3045,7 +3045,109 @@
}
}
+typedef struct {
+ void *buffer;
+ target_phys_addr_t addr;
+ target_phys_addr_t len;
+} BounceBuffer;
+static BounceBuffer bounce;
+
+/* Map a physical memory region into a host virtual address.
+ * May map a subset of the requested range, given by and returned in *plen.
+ * May return NULL if resources needed to perform the mapping are exhausted.
+ * Use only for reads OR writes - not for read-modify-write operations.
+ */
+void *cpu_physical_memory_map(target_phys_addr_t addr,
+ target_phys_addr_t *plen,
+ int is_write)
+{
+ target_phys_addr_t len = *plen;
+ target_phys_addr_t done = 0;
+ int l;
+ uint8_t *ret = NULL;
+ uint8_t *ptr;
+ target_phys_addr_t page;
+ unsigned long pd;
+ PhysPageDesc *p;
+ unsigned long addr1;
+
+ while (len > 0) {
+ page = addr & TARGET_PAGE_MASK;
+ l = (page + TARGET_PAGE_SIZE) - addr;
+ if (l > len)
+ l = len;
+ p = phys_page_find(page >> TARGET_PAGE_BITS);
+ if (!p) {
+ pd = IO_MEM_UNASSIGNED;
+ } else {
+ pd = p->phys_offset;
+ }
+
+ if ((pd & ~TARGET_PAGE_MASK) != IO_MEM_RAM) {
+ if (done || bounce.buffer) {
+ break;
+ }
+ bounce.buffer = qemu_memalign(TARGET_PAGE_SIZE, TARGET_PAGE_SIZE);
+ bounce.addr = addr;
+ bounce.len = l;
+ if (!is_write) {
+ cpu_physical_memory_rw(addr, bounce.buffer, l, 0);
+ }
+ ptr = bounce.buffer;
+ } else {
+ addr1 = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+ ptr = phys_ram_base + addr1;
+ }
+ if (!done) {
+ ret = ptr;
+ } else if (ret + done != ptr) {
+ break;
+ }
+
+ len -= l;
+ addr += l;
+ done += l;
+ }
+ *plen = done;
+ return ret;
+}
+
+/* Unmaps a memory region previously mapped by cpu_physical_memory_map().
+ * Will also mark the memory as dirty if is_write == 1. access_len gives
+ * the amount of memory that was actually read or written by the caller.
+ */
+void cpu_physical_memory_unmap(void *buffer, target_phys_addr_t len,
+ int is_write, target_phys_addr_t access_len)
+{
+ if (buffer != bounce.buffer) {
+ if (is_write) {
+ unsigned long addr1 = (uint8_t *)buffer - phys_ram_base;
+ while (access_len) {
+ unsigned l;
+ l = TARGET_PAGE_SIZE;
+ if (l > access_len)
+ l = access_len;
+ if (!cpu_physical_memory_is_dirty(addr1)) {
+ /* invalidate code */
+ tb_invalidate_phys_page_range(addr1, addr1 + l, 0);
+ /* set dirty bit */
+ phys_ram_dirty[addr1 >> TARGET_PAGE_BITS] |=
+ (0xff & ~CODE_DIRTY_FLAG);
+ }
+ addr1 += l;
+ access_len -= l;
+ }
+ }
+ return;
+ }
+ if (is_write) {
+ cpu_physical_memory_write(bounce.addr, bounce.buffer, access_len);
+ }
+ qemu_free(bounce.buffer);
+ bounce.buffer = NULL;
+}
+
/* warning: addr must be aligned */
uint32_t ldl_phys(target_phys_addr_t addr)
{
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