feat(vmm): Add Paging support

2025-04-17 21:54:25 +02:00
parent 0b77abfc23
commit 2515149f28
14 changed files with 266 additions and 11 deletions
@@ -0,0 +1,91 @@
+#include "Paging.hpp"
+#include <Memory/PageFrameAllocator.hpp>
+#include <Common/Panic.hpp>
+#include <Memory/HHDM.hpp>
+
+namespace Memory::VMM {
+    extern "C" uint64_t KernelStartSymbol;
+    
+    std::uint64_t GetPhysKernelAddress(std::uint64_t virtualAddress) {
+        return Paging::GetPhysAddr(GetCR3(), (std::uint64_t)virtualAddress, true);
+    }
+
+    Paging::Paging() {
+        PML4 = (PageTable*)SubHHDM((PageTable*)Memory::g_pfa->AllocateZeroed());
+    }
+
+    void Paging::Init(std::uint64_t kernelBaseVirt, std::uint64_t kernelSize) {
+        // Map kernel
+        Kt::KernelLogStream(Kt::DEBUG, "VMM") << "Paging::Init called with kernelBaseVirt as 0x" << base::hex << kernelBaseVirt << " and kernelSize as " << base::dec << kernelSize;
+
+        for (std::uint64_t pageAddr = kernelBaseVirt; pageAddr < (kernelBaseVirt + kernelSize); pageAddr += 0x1000) {
+            Kt::KernelLogStream(Kt::DEBUG, "VMM") << "Mapping 0x" << base::hex << GetPhysKernelAddress(pageAddr) << " to 0x" << pageAddr;
+            Map(GetPhysKernelAddress(pageAddr), pageAddr);
+        }
+
+        // TODO map HHDM
+        // TODO map ACPI tables
+
+        LoadCR3((PageTable*)&PML4);
+    }
+
+    PageTable* Paging::HandleLevel(VirtualAddress virtualAddress, PageTable* table, const size_t level) {
+        PageTableEntry* entry = (PageTableEntry*)Memory::HHDM(&table->entries[virtualAddress.GetIndex(level)]);
+        
+        entry->Present = true;
+        entry->Writable = true;
+
+        uint64_t downLevelAddr = Memory::SubHHDM((uint64_t)Memory::g_pfa->AllocateZeroed());
+
+        entry->Address = downLevelAddr >> 12;
+
+        return (PageTable*)downLevelAddr;
+    }
+
+    void Paging::Map(std::uint64_t physicalAddress, std::uint64_t virtualAddress) {
+        if (virtualAddress % 0x1000 != 0 || physicalAddress % 0x1000 != 0) {
+            Panic("Value that isn't page-aligned passed as address to Paging::Map!", nullptr);
+        }
+
+        VirtualAddress virtualAddressObj(virtualAddress);
+
+        auto PML3 = HandleLevel(virtualAddressObj, PML4, 4);
+        auto PML2 = HandleLevel(virtualAddressObj, PML3, 3);
+        auto PML1 = HandleLevel(virtualAddressObj, PML2, 2);
+
+        PageTableEntry* pageEntry = (PageTableEntry*)Memory::HHDM(&PML1->entries[virtualAddressObj.GetPageIndex()]);
+
+        pageEntry->Present = true;
+        pageEntry->Writable = true;
+
+        pageEntry->Address = virtualAddress >> 12;
+    }
+
+    std::uint64_t Paging::GetPhysAddr(std::uint64_t pml4, std::uint64_t virtualAddress, bool use40BitL1) {
+        VirtualAddress virtualAddressObj(virtualAddress);
+        
+        PageTable* pml4Virt = (PageTable*)HHDM(pml4);
+
+        PageTableEntry* pml4_entry = &pml4Virt->entries[virtualAddressObj.GetL4Index()];
+
+        PageTable* pml3 = (PageTable*)HHDM(pml4_entry->Address << 12);
+        PageTableEntry* pml3_entry = &pml3->entries[virtualAddressObj.GetL3Index()];
+
+        PageTable* pml2 = (PageTable*)HHDM(pml3_entry->Address << 12);
+        PageTableEntry* pml2_entry = &pml2->entries[virtualAddressObj.GetL2Index()];
+
+        PageTable* pml1 = (PageTable*)HHDM(pml2_entry->Address << 12);
+
+        if (use40BitL1 == true) {
+            PageTableEntry40Bit* pml1_entry = (PageTableEntry40Bit*)&pml1->entries[virtualAddressObj.GetPageIndex()];
+            return (uint64_t)pml1_entry->Address << 12;
+        }
+
+        PageTableEntry* pml1_entry = &pml1->entries[virtualAddressObj.GetPageIndex()];
+        return (uint64_t)pml1_entry->Address << 12;
+    }
+
+    std::uint64_t Paging::GetPhysAddr(std::uint64_t virtualAddress) {
+        return GetPhysAddr((std::uint64_t)PML4, virtualAddress, false);
+    }
+};