Kernel: Add GeneralAllocator::paddr_of

Yoy can now query physical address of a virtual address for general
allocator allocation

kernel/include/kernel/Memory/GeneralAllocator.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <BAN/LinkedList.h>
+#include <BAN/Optional.h>
 #include <BAN/UniqPtr.h>
 #include <kernel/Memory/Heap.h>
 #include <kernel/Memory/PageTable.h>
@@ -19,6 +20,8 @@ namespace Kernel
 
 		BAN::ErrorOr<BAN::UniqPtr<GeneralAllocator>> clone(PageTable&);
 
+		BAN::Optional<paddr_t> paddr_of(vaddr_t);
+
 		vaddr_t allocate(size_t);
 		bool deallocate(vaddr_t);
 
@@ -30,12 +33,14 @@ namespace Kernel
 		{
 			vaddr_t address { 0 };
 			BAN::Vector<paddr_t> pages;
+
+			bool contains(vaddr_t);
 		};
 
 	private:
-		const vaddr_t m_first_vaddr;
 		PageTable& m_page_table;
 		BAN::LinkedList<Allocation> m_allocations;
+		const vaddr_t m_first_vaddr;
 	};
 
 }

kernel/kernel/Memory/GeneralAllocator.cpp

@@ -51,9 +51,11 @@ namespace Kernel
 		{
 			vaddr_t vaddr = allocation.address + i * PAGE_SIZE;
 			m_page_table.map_page_at(allocation.pages[i], vaddr, PageTable::Flags::UserSupervisor | PageTable::Flags::ReadWrite | PageTable::Flags::Present);
-			m_page_table.invalidate(vaddr);
 		}
 
+		if (&m_page_table == &PageTable::current())
+			m_page_table.load();
+
 		m_page_table.unlock();
 
 		MUST(m_allocations.push_back(BAN::move(allocation)));
@@ -121,4 +123,25 @@ namespace Kernel
 		return allocator;
 	}
 
+	BAN::Optional<paddr_t> GeneralAllocator::paddr_of(vaddr_t vaddr)
+	{
+		for (auto& allocation : m_allocations)
+		{
+			if (!allocation.contains(vaddr))
+				continue;
+			
+			size_t offset = vaddr - allocation.address;
+			size_t page_index = offset / PAGE_SIZE;
+			size_t page_offset = offset % PAGE_SIZE;
+			return allocation.pages[page_index] + page_offset;
+		}
+
+		return {};
+	}
+
+	bool GeneralAllocator::Allocation::contains(vaddr_t vaddr)
+	{
+		return this->address <= vaddr && vaddr < this->address + this->pages.size() * PAGE_SIZE;
+	}
+
 }