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Kernel: Flush TLB when quick-mapping PD/PT that was mapped on other CPU

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If a PD/PT was quick-mapped by another CPU we still need to flush the
TLB on the current CPU.

Fixes #3885
This commit is contained in:
Tom 2020-10-31 17:19:50 -06:00 • committed by Andreas Kling
parent 8c4a2c34d3
commit 13aa3d2d62
2 changed files with 19 additions and 0 deletions
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16
Kernel/VM/MemoryManager.cpp
View file

@ -648,6 +648,7 @@ extern "C" PageTableEntry boot_pd3_pt1023[1024];
PageDirectoryEntry* MemoryManager::quickmap_pd(PageDirectory& directory, size_t pdpt_index)
{
ASSERT(s_mm_lock.own_lock());
auto& mm_data = get_data();
auto& pte = boot_pd3_pt1023[4];
auto pd_paddr = directory.m_directory_pages[pdpt_index]->paddr();
if (pte.physical_page_base() != pd_paddr.as_ptr()) {
@ -662,13 +663,21 @@ PageDirectoryEntry* MemoryManager::quickmap_pd(PageDirectory& directory, size_t
// mapping, it is sufficient to only flush on the current CPU. Other
// CPUs trying to use this API must wait on the MM lock anyway
flush_tlb_local(VirtualAddress(0xffe04000));
} else {
// Even though we don't allow this to be called concurrently, it's
// possible that this PD was mapped on a different CPU and we don't
// broadcast the flush. If so, we still need to flush the TLB.
if (mm_data.m_last_quickmap_pd != pd_paddr)
flush_tlb_local(VirtualAddress(0xffe04000));
}
mm_data.m_last_quickmap_pd = pd_paddr;
return (PageDirectoryEntry*)0xffe04000;
}
PageTableEntry* MemoryManager::quickmap_pt(PhysicalAddress pt_paddr)
{
ASSERT(s_mm_lock.own_lock());
auto& mm_data = get_data();
auto& pte = boot_pd3_pt1023[0];
if (pte.physical_page_base() != pt_paddr.as_ptr()) {
#ifdef MM_DEBUG
@ -682,7 +691,14 @@ PageTableEntry* MemoryManager::quickmap_pt(PhysicalAddress pt_paddr)
// mapping, it is sufficient to only flush on the current CPU. Other
// CPUs trying to use this API must wait on the MM lock anyway
flush_tlb_local(VirtualAddress(0xffe00000));
} else {
// Even though we don't allow this to be called concurrently, it's
// possible that this PT was mapped on a different CPU and we don't
// broadcast the flush. If so, we still need to flush the TLB.
if (mm_data.m_last_quickmap_pt != pt_paddr)
flush_tlb_local(VirtualAddress(0xffe00000));
}
mm_data.m_last_quickmap_pt = pt_paddr;
return (PageTableEntry*)0xffe00000;
}

3
Kernel/VM/MemoryManager.h
View file

@ -70,6 +70,9 @@ class SynthFSInode;
struct MemoryManagerData {
SpinLock<u8> m_quickmap_in_use;
u32 m_quickmap_prev_flags;
PhysicalAddress m_last_quickmap_pd;
PhysicalAddress m_last_quickmap_pt;
};
extern RecursiveSpinLock s_mm_lock;