common/host_memory: Implement a fallback if fastmem fails.

This falls back to the old approach of using a virtual buffer.

Windows is untested, but this build should fix support for Windows < 10 v1803. However without fastmem support at all.
This commit is contained in:
Markus Wick 2021-06-11 11:47:23 +02:00
parent f332d4a9b5
commit 7f85abb281
2 changed files with 49 additions and 14 deletions

View file

@ -449,23 +449,54 @@ private:
int fd{-1}; // memfd file descriptor, -1 is the error value of memfd_create
};
#else // ^^^ Linux ^^^
#else // ^^^ Linux ^^^ vvv Generic vvv
#error Please implement the host memory for your platform
class HostMemory::Impl {
public:
explicit Impl(size_t /*backing_size */, size_t /* virtual_size */) {
// This is just a place holder.
// Please implement fastmem in a propper way on your platform.
throw std::bad_alloc{};
}
#endif
void Map(size_t virtual_offset, size_t host_offset, size_t length) {}
void Unmap(size_t virtual_offset, size_t length) {}
void Protect(size_t virtual_offset, size_t length, bool read, bool write) {}
u8* backing_base{nullptr};
u8* virtual_base{nullptr};
};
#endif // ^^^ Generic ^^^
HostMemory::HostMemory(size_t backing_size_, size_t virtual_size_)
: backing_size(backing_size_),
virtual_size(virtual_size_), impl{std::make_unique<HostMemory::Impl>(
AlignUp(backing_size, PageAlignment),
AlignUp(virtual_size, PageAlignment) + 3 * HugePageSize)},
backing_base{impl->backing_base}, virtual_base{impl->virtual_base} {
: backing_size(backing_size_), virtual_size(virtual_size_) {
try {
// Try to allocate a fastmem arena.
// The implementation will fail with std::bad_alloc on errors.
impl = std::make_unique<HostMemory::Impl>(AlignUp(backing_size, PageAlignment),
AlignUp(virtual_size, PageAlignment) +
3 * HugePageSize);
backing_base = impl->backing_base;
virtual_base = impl->virtual_base;
if (virtual_base) {
virtual_base += 2 * HugePageSize - 1;
virtual_base -= reinterpret_cast<size_t>(virtual_base) & (HugePageSize - 1);
virtual_base_offset = virtual_base - impl->virtual_base;
}
} catch (const std::bad_alloc&) {
LOG_CRITICAL(HW_Memory,
"Fastmem unavailable, falling back to VirtualBuffer for memory allocation");
fallback_buffer = std::make_unique<Common::VirtualBuffer<u8>>(backing_size);
backing_base = fallback_buffer->data();
virtual_base = nullptr;
}
}
HostMemory::~HostMemory() = default;
HostMemory::HostMemory(HostMemory&&) noexcept = default;
@ -478,7 +509,7 @@ void HostMemory::Map(size_t virtual_offset, size_t host_offset, size_t length) {
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= virtual_size);
ASSERT(host_offset + length <= backing_size);
if (length == 0) {
if (length == 0 || !virtual_base || !impl) {
return;
}
impl->Map(virtual_offset + virtual_base_offset, host_offset, length);
@ -488,7 +519,7 @@ void HostMemory::Unmap(size_t virtual_offset, size_t length) {
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= virtual_size);
if (length == 0) {
if (length == 0 || !virtual_base || !impl) {
return;
}
impl->Unmap(virtual_offset + virtual_base_offset, length);
@ -498,7 +529,7 @@ void HostMemory::Protect(size_t virtual_offset, size_t length, bool read, bool w
ASSERT(virtual_offset % PageAlignment == 0);
ASSERT(length % PageAlignment == 0);
ASSERT(virtual_offset + length <= virtual_size);
if (length == 0) {
if (length == 0 || !virtual_base || !impl) {
return;
}
impl->Protect(virtual_offset + virtual_base_offset, length, read, write);

View file

@ -6,6 +6,7 @@
#include <memory>
#include "common/common_types.h"
#include "common/virtual_buffer.h"
namespace Common {
@ -61,6 +62,9 @@ private:
u8* backing_base{};
u8* virtual_base{};
size_t virtual_base_offset{};
// Fallback if fastmem is not supported on this platform
std::unique_ptr<Common::VirtualBuffer<u8>> fallback_buffer;
};
} // namespace Common