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From bd32a130ca633eae7cf0f4ff0fa856004d413df0 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Thu, 27 May 2021 15:27:55 +0200
Subject: [PATCH 5/8] memory: add MemoryRegion map and unmap callbacks
In order to support mapping and unmapping guest memory dynamically to
and from qemu during address_space_[un]map() operations add the map()
and unmap() callbacks to MemoryRegionOps.
Those will be used e.g. for Xen grant mappings when performing guest
I/Os.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
Acked-by: Stefano Stabellini <stefano.stabellini@amd.com>
---
include/exec/memory.h | 19 +++++++++++++++++
softmmu/physmem.c | 47 +++++++++++++++++++++++++++++++++----------
2 files changed, 55 insertions(+), 11 deletions(-)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index bfb1de8eea..19e2aac694 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -245,6 +245,25 @@ struct MemoryRegionOps {
unsigned size,
MemTxAttrs attrs);
+ /* Dynamically create mapping. @addr is the guest address to map; @plen
+ * is the pointer to the usable length of the buffer.
+ * @mr contents can be changed in case a new memory region is created for
+ * the mapping.
+ * Returns the buffer address for accessing the data. */
+ void *(*map)(MemoryRegion **mr,
+ hwaddr addr,
+ hwaddr *plen,
+ bool is_write,
+ MemTxAttrs attrs);
+
+ /* Unmap an area obtained via map() before. */
+ void (*unmap)(MemoryRegion *mr,
+ void *buffer,
+ ram_addr_t addr,
+ hwaddr len,
+ bool is_write,
+ hwaddr access_len);
+
enum device_endian endianness;
/* Guest-visible constraints: */
struct {
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 439a53a1be..2038240311 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -3237,7 +3237,7 @@ void *address_space_map(AddressSpace *as,
hwaddr len = *plen;
hwaddr l, xlat;
MemoryRegion *mr;
- void *ptr;
+ void *ptr = NULL;
FlatView *fv;
if (len == 0) {
@@ -3273,10 +3273,17 @@ void *address_space_map(AddressSpace *as,
memory_region_ref(mr);
+
+ if (mr->ops && mr->ops->map) {
+ ptr = mr->ops->map(&mr, addr, plen, is_write, attrs);
+ }
+
*plen = flatview_extend_translation(fv, addr, len, mr, xlat,
l, is_write, attrs);
fuzz_dma_read_cb(addr, *plen, mr);
- ptr = qemu_ram_ptr_length(mr->ram_block, xlat, plen, true);
+ if (ptr == NULL) {
+ ptr = qemu_ram_ptr_length(mr->ram_block, xlat, plen, true);
+ }
return ptr;
}
@@ -3294,11 +3301,16 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
mr = memory_region_from_host(buffer, &addr1);
assert(mr != NULL);
- if (is_write) {
- invalidate_and_set_dirty(mr, addr1, access_len);
- }
- if (xen_enabled()) {
- xen_invalidate_map_cache_entry(buffer);
+
+ if (mr->ops && mr->ops->unmap) {
+ mr->ops->unmap(mr, buffer, addr1, len, is_write, access_len);
+ } else {
+ if (is_write) {
+ invalidate_and_set_dirty(mr, addr1, access_len);
+ }
+ if (xen_enabled()) {
+ xen_invalidate_map_cache_entry(buffer);
+ }
}
memory_region_unref(mr);
return;
@@ -3370,10 +3382,17 @@ int64_t address_space_cache_init(MemoryRegionCache *cache,
* doing this if we found actual RAM, which behaves the same
* regardless of attributes; so UNSPECIFIED is fine.
*/
+ if (mr->ops && mr->ops->map) {
+ cache->ptr = mr->ops->map(&mr, addr, &l, is_write,
+ MEMTXATTRS_UNSPECIFIED);
+ }
+
l = flatview_extend_translation(cache->fv, addr, len, mr,
cache->xlat, l, is_write,
MEMTXATTRS_UNSPECIFIED);
- cache->ptr = qemu_ram_ptr_length(mr->ram_block, cache->xlat, &l, true);
+ if (!cache->ptr) {
+ cache->ptr = qemu_ram_ptr_length(mr->ram_block, cache->xlat, &l, true);
+ }
} else {
cache->ptr = NULL;
}
@@ -3395,14 +3414,20 @@ void address_space_cache_invalidate(MemoryRegionCache *cache,
void address_space_cache_destroy(MemoryRegionCache *cache)
{
- if (!cache->mrs.mr) {
+ MemoryRegion *mr = cache->mrs.mr;
+
+ if (!mr) {
return;
}
- if (xen_enabled()) {
+ if (mr->ops && mr->ops->unmap) {
+ mr->ops->unmap(mr, cache->ptr, cache->xlat, cache->len,
+ cache->is_write, cache->len);
+ } else if (xen_enabled()) {
xen_invalidate_map_cache_entry(cache->ptr);
}
- memory_region_unref(cache->mrs.mr);
+
+ memory_region_unref(mr);
flatview_unref(cache->fv);
cache->mrs.mr = NULL;
cache->fv = NULL;
--
2.25.1
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