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Kernel/IPC: Partially implement MappedBuffer translation.

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Right now only MappedBuffers that only span a single page and are not aligned are implemented.

MappedBuffers are unmapped during the reply part of ReplyAndReceive. Only unmapping of ReadOnly buffers is currently implemented.
This commit is contained in:
Subv 2017-11-07 14:35:17 -05:00
parent 928202f744
commit a7a5c5aa0d
5 changed files with 102 additions and 14 deletions
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85
src/core/hle/kernel/ipc.cpp
View file

@ -2,6 +2,7 @@
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "common/alignment.h"
#include "core/hle/ipc.h"
#include "core/hle/kernel/handle_table.h"
#include "core/hle/kernel/ipc.h"
@ -14,7 +15,7 @@
namespace Kernel {
ResultCode TranslateCommandBuffer(SharedPtr<Thread> src_thread, SharedPtr<Thread> dst_thread,
VAddr src_address, VAddr dst_address) {
VAddr src_address, VAddr dst_address, bool reply) {
auto& src_process = src_thread->owner_process;
auto& dst_process = dst_thread->owner_process;
@ -115,6 +116,88 @@ ResultCode TranslateCommandBuffer(SharedPtr<Thread> src_thread, SharedPtr<Thread
cmd_buf[i++] = target_buffer.address;
break;
}
case IPC::DescriptorType::MappedBuffer: {
IPC::MappedBufferDescInfo descInfo{descriptor};
VAddr source_address = cmd_buf[i];
size_t size = descInfo.size;
IPC::MappedBufferPermissions permissions = descInfo.perms;
VAddr page_start = Common::AlignDown(source_address, Memory::PAGE_SIZE);
u32 page_offset = source_address - page_start;
u32 num_pages =
Common::AlignUp(page_offset + size, Memory::PAGE_SIZE) >> Memory::PAGE_BITS;
ASSERT(num_pages >= 1);
if (reply) {
// TODO(Subv): Scan the target's command buffer to make sure that there was a
// MappedBuffer descriptor in the original request. The real kernel panics if you
// try to reply with an unsolicited MappedBuffer.
// Unmap the buffers. Readonly buffers do not need to be copied over to the target
// process again because they were (presumably) not modified. This behavior is
// consistent with the real kernel.
if (permissions == IPC::MappedBufferPermissions::R) {
ResultCode result = src_process->vm_manager.UnmapRange(
page_start, num_pages * Memory::PAGE_SIZE);
ASSERT(result == RESULT_SUCCESS);
}
ASSERT_MSG(permissions == IPC::MappedBufferPermissions::R,
"Unmapping Write MappedBuffers is unimplemented");
i += 1;
break;
}
VAddr target_address = 0;
auto IsPageAligned = [](VAddr address) -> bool {
return (address & Memory::PAGE_MASK) == 0;
};
// TODO(Subv): Support more than 1 page and aligned page mappings
ASSERT_MSG(
num_pages == 1 &&
(!IsPageAligned(source_address) || !IsPageAligned(source_address + size)),
"MappedBuffers of more than one page or aligned transfers are not implemented");
// TODO(Subv): Perform permission checks.
// TODO(Subv): Leave a page of Reserved memory before the first page and after the last
// page.
if (!IsPageAligned(source_address) ||
(num_pages == 1 && !IsPageAligned(source_address + size))) {
// If the address of the source buffer is not page-aligned or if the buffer doesn't
// fill an entire page, then we have to allocate a page of memory in the target
// process and copy over the data from the input buffer. This allocated buffer will
// be copied back to the source process and deallocated when the server replies to
// the request via ReplyAndReceive.
auto buffer = std::make_shared<std::vector<u8>>(Memory::PAGE_SIZE);
// Number of bytes until the next page.
size_t difference_to_page =
Common::AlignUp(source_address, Memory::PAGE_SIZE) - source_address;
// If the data fits in one page we can just copy the required size instead of the
// entire page.
size_t read_size = num_pages == 1 ? size : difference_to_page;
Memory::ReadBlock(*src_process, source_address, buffer->data() + page_offset,
read_size);
// Map the page into the target process' address space.
target_address = dst_process->vm_manager
.MapMemoryBlockToBase(
Memory::IPC_MAPPING_VADDR, Memory::IPC_MAPPING_SIZE,
buffer, 0, buffer->size(), Kernel::MemoryState::Shared)
.Unwrap();
}
cmd_buf[i++] = target_address + page_offset;
break;
}
default:
UNIMPLEMENTED_MSG("Unsupported handle translation: 0x%08X", descriptor);
}

2
src/core/hle/kernel/ipc.h
View file

@ -10,5 +10,5 @@
namespace Kernel {
/// Performs IPC command buffer translation from one process to another.
ResultCode TranslateCommandBuffer(SharedPtr<Thread> src_thread, SharedPtr<Thread> dst_thread,
VAddr src_address, VAddr dst_address);
VAddr src_address, VAddr dst_address, bool reply);
} // namespace Kernel

8
src/core/hle/kernel/svc.cpp
View file

@ -472,8 +472,8 @@ static ResultCode ReceiveIPCRequest(SharedPtr<ServerSession> server_session,
VAddr target_address = thread->GetCommandBufferAddress();
VAddr source_address = server_session->currently_handling->GetCommandBufferAddress();
ResultCode translation_result = TranslateCommandBuffer(server_session->currently_handling,
thread, source_address, target_address);
ResultCode translation_result = TranslateCommandBuffer(
server_session->currently_handling, thread, source_address, target_address, false);
// If a translation error occurred, immediately resume the client thread.
if (translation_result.IsError()) {
@ -535,8 +535,8 @@ static ResultCode ReplyAndReceive(s32* index, VAddr handles_address, s32 handle_
VAddr source_address = GetCurrentThread()->GetCommandBufferAddress();
VAddr target_address = request_thread->GetCommandBufferAddress();
ResultCode translation_result = TranslateCommandBuffer(GetCurrentThread(), request_thread,
source_address, target_address);
ResultCode translation_result = TranslateCommandBuffer(
Kernel::GetCurrentThread(), request_thread, source_address, target_address, true);
// Note: The real kernel seems to always panic if the Server->Client buffer translation
// fails for whatever reason.

13
src/core/hle/kernel/vm_manager.cpp
View file

@ -93,7 +93,8 @@ ResultVal<VMManager::VMAHandle> VMManager::MapMemoryBlock(VAddr target,
return MakeResult<VMAHandle>(MergeAdjacent(vma_handle));
}
ResultVal<VAddr> VMManager::MapMemoryBlockToBase(VAddr base, std::shared_ptr<std::vector<u8>> block,
ResultVal<VAddr> VMManager::MapMemoryBlockToBase(VAddr base, u32 region_size,
std::shared_ptr<std::vector<u8>> block,
size_t offset, u32 size, MemoryState state) {
// Find the first Free VMA.
@ -105,13 +106,15 @@ ResultVal<VAddr> VMManager::MapMemoryBlockToBase(VAddr base, std::shared_ptr<std
return vma_end > base && vma_end >= base + size;
});
if (vma_handle == vma_map.end()) {
VAddr target = std::max(base, vma_handle->second.base);
// Do not try to allocate the block if there are no available addresses within the desired
// region.
if (vma_handle == vma_map.end() || target + size > base + region_size) {
return ResultCode(ErrorDescription::OutOfMemory, ErrorModule::Kernel,
ErrorSummary::OutOfResource, ErrorLevel::Permanent);
}
VAddr target = std::max(base, vma_handle->second.base);
auto result = MapMemoryBlock(target, block, offset, size, state);
if (result.Failed())
@ -373,4 +376,4 @@ void VMManager::UpdatePageTableForVMA(const VirtualMemoryArea& vma) {
break;
}
}
}
} // namespace Kernel

8
src/core/hle/kernel/vm_manager.h
View file

@ -148,14 +148,16 @@ public:
* Maps part of a ref-counted block of memory at the first free address after the given base.
*
* @param base The base address to start the mapping at.
* @param region_size The max size of the region from where we'll try to find an address.
* @param block The block to be mapped.
* @param offset Offset into `block` to map from.
* @param size Size of the mapping.
* @param state MemoryState tag to attach to the VMA.
* @returns The address at which the memory was mapped.
*/
ResultVal<VAddr> MapMemoryBlockToBase(VAddr base, std::shared_ptr<std::vector<u8>> block,
size_t offset, u32 size, MemoryState state);
ResultVal<VAddr> MapMemoryBlockToBase(VAddr base, u32 region_size,
std::shared_ptr<std::vector<u8>> block, size_t offset,
u32 size, MemoryState state);
/**
* Maps an unmanaged host memory pointer at a given address.
*
@ -236,4 +238,4 @@ private:
/// Updates the pages corresponding to this VMA so they match the VMA's attributes.
void UpdatePageTableForVMA(const VirtualMemoryArea& vma);
};
}
} // namespace Kernel