Rust side will use cell::Opaque<> to hide details of C structure, and
this could help avoid the direct operation on C memory from Rust side.
Therefore, it's necessary to wrap a translation binding and make it only
return the pointer to MemoryRegionSection, instead of the copy.
As the first step, make flatview_do_translate return a pointer to
MemoryRegionSection, so that we can build a wrapper based on it.
In addtion, add a global variable `unassigned_section` to help get a
pointer to an invalid MemoryRegionSection.
Signed-off-by: Zhao Liu <zhao1....@intel.com>
---
system/physmem.c | 51 ++++++++++++++++++++++--------------------------
1 file changed, 23 insertions(+), 28 deletions(-)
diff --git a/system/physmem.c b/system/physmem.c
index 785c9a4050c6..4af29ea2168e 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -103,6 +103,9 @@ AddressSpace address_space_io;
AddressSpace address_space_memory;
static MemoryRegion io_mem_unassigned;
+static MemoryRegionSection unassigned_section = {
+ .mr = &io_mem_unassigned
+};
typedef struct PhysPageEntry PhysPageEntry;
@@ -418,14 +421,11 @@ address_space_translate_internal(AddressSpaceDispatch *d,
hwaddr addr, hwaddr *x
* This function is called from RCU critical section. It is the common
* part of flatview_do_translate and address_space_translate_cached.
*/
-static MemoryRegionSection address_space_translate_iommu(IOMMUMemoryRegion
*iommu_mr,
- hwaddr *xlat,
- hwaddr *plen_out,
- hwaddr *page_mask_out,
- bool is_write,
- bool is_mmio,
- AddressSpace
**target_as,
- MemTxAttrs attrs)
+static MemoryRegionSection *
+address_space_translate_iommu(IOMMUMemoryRegion *iommu_mr, hwaddr *xlat,
+ hwaddr *plen_out, hwaddr *page_mask_out,
+ bool is_write, bool is_mmio,
+ AddressSpace **target_as, MemTxAttrs attrs)
{
MemoryRegionSection *section;
hwaddr page_mask = (hwaddr)-1;
@@ -463,10 +463,10 @@ static MemoryRegionSection
address_space_translate_iommu(IOMMUMemoryRegion *iomm
if (page_mask_out) {
*page_mask_out = page_mask;
}
- return *section;
+ return section;
unassigned:
- return (MemoryRegionSection) { .mr = &io_mem_unassigned };
+ return &unassigned_section;
}
/**
@@ -489,15 +489,10 @@ unassigned:
*
* This function is called from RCU critical section
*/
-static MemoryRegionSection flatview_do_translate(FlatView *fv,
- hwaddr addr,
- hwaddr *xlat,
- hwaddr *plen_out,
- hwaddr *page_mask_out,
- bool is_write,
- bool is_mmio,
- AddressSpace **target_as,
- MemTxAttrs attrs)
+static MemoryRegionSection *
+flatview_do_translate(FlatView *fv, hwaddr addr, hwaddr *xlat, hwaddr
*plen_out,
+ hwaddr *page_mask_out, bool is_write, bool is_mmio,
+ AddressSpace **target_as, MemTxAttrs attrs)
{
MemoryRegionSection *section;
IOMMUMemoryRegion *iommu_mr;
@@ -523,14 +518,14 @@ static MemoryRegionSection flatview_do_translate(FlatView
*fv,
*page_mask_out = ~TARGET_PAGE_MASK;
}
- return *section;
+ return section;
}
/* Called from RCU critical section */
IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr,
bool is_write, MemTxAttrs attrs)
{
- MemoryRegionSection section;
+ MemoryRegionSection *section;
hwaddr xlat, page_mask;
/*
@@ -542,13 +537,13 @@ IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace
*as, hwaddr addr,
attrs);
/* Illegal translation */
- if (section.mr == &io_mem_unassigned) {
+ if (section->mr == &io_mem_unassigned) {
goto iotlb_fail;
}
/* Convert memory region offset into address space offset */
- xlat += section.offset_within_address_space -
- section.offset_within_region;
+ xlat += section->offset_within_address_space -
+ section->offset_within_region;
return (IOMMUTLBEntry) {
.target_as = as,
@@ -569,13 +564,13 @@ MemoryRegion *flatview_translate(FlatView *fv, hwaddr
addr, hwaddr *xlat,
MemTxAttrs attrs)
{
MemoryRegion *mr;
- MemoryRegionSection section;
+ MemoryRegionSection *section;
AddressSpace *as = NULL;
/* This can be MMIO, so setup MMIO bit. */
section = flatview_do_translate(fv, addr, xlat, plen, NULL,
is_write, true, &as, attrs);
- mr = section.mr;
+ mr = section->mr;
if (xen_enabled() && memory_access_is_direct(mr, is_write, attrs)) {
hwaddr page = ((addr & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE) - addr;
@@ -3618,7 +3613,7 @@ static inline MemoryRegion
*address_space_translate_cached(
MemoryRegionCache *cache, hwaddr addr, hwaddr *xlat,
hwaddr *plen, bool is_write, MemTxAttrs attrs)
{
- MemoryRegionSection section;
+ MemoryRegionSection *section;
MemoryRegion *mr;
IOMMUMemoryRegion *iommu_mr;
AddressSpace *target_as;
@@ -3636,7 +3631,7 @@ static inline MemoryRegion
*address_space_translate_cached(
section = address_space_translate_iommu(iommu_mr, xlat, plen,
NULL, is_write, true,
&target_as, attrs);
- return section.mr;
+ return section->mr;
}
/* Called within RCU critical section. */
--
2.34.1
