From b18589ecf780ca479e077529b789ec481e58f715 Mon Sep 17 00:00:00 2001 From: Subv Date: Sun, 1 Oct 2017 13:57:50 -0500 Subject: [PATCH] Kernel/SharedMemory: Don't take over and unmap the source memory block when creating a shared memory, just reference it. Also reference the right offset into the backing block for the requested address. --- src/core/hle/kernel/shared_memory.cpp | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/src/core/hle/kernel/shared_memory.cpp b/src/core/hle/kernel/shared_memory.cpp index 02d5a7a36..d45daca35 100644 --- a/src/core/hle/kernel/shared_memory.cpp +++ b/src/core/hle/kernel/shared_memory.cpp @@ -55,22 +55,19 @@ SharedPtr SharedMemory::Create(SharedPtr owner_process, u Kernel::g_current_process->vm_manager.RefreshMemoryBlockMappings(linheap_memory.get()); } } else { - // TODO(Subv): What happens if an application tries to create multiple memory blocks - // pointing to the same address? auto& vm_manager = shared_memory->owner_process->vm_manager; // The memory is already available and mapped in the owner process. - auto vma = vm_manager.FindVMA(address)->second; - // Copy it over to our own storage - shared_memory->backing_block = std::make_shared>( - vma.backing_block->data() + vma.offset, vma.backing_block->data() + vma.offset + size); - shared_memory->backing_block_offset = 0; - // Unmap the existing pages - vm_manager.UnmapRange(address, size); - // Map our own block into the address space - vm_manager.MapMemoryBlock(address, shared_memory->backing_block, 0, size, - MemoryState::Shared); - // Reprotect the block with the new permissions - vm_manager.ReprotectRange(address, size, ConvertPermissions(permissions)); + auto vma = vm_manager.FindVMA(address); + ASSERT_MSG(vma != vm_manager.vma_map.end(), "Invalid memory address"); + ASSERT_MSG(vma->second.backing_block, "Backing block doesn't exist for address"); + + // The returned VMA might be a bigger one encompassing the desired address. + auto vma_offset = address - vma->first; + ASSERT_MSG(vma_offset + size <= vma->second.size, + "Shared memory exceeds bounds of mapped block"); + + shared_memory->backing_block = vma->second.backing_block; + shared_memory->backing_block_offset = vma->second.offset + vma_offset; } shared_memory->base_address = address; @@ -184,4 +181,4 @@ u8* SharedMemory::GetPointer(u32 offset) { return backing_block->data() + backing_block_offset + offset; } -} // namespace +} // namespace Kernel