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Fix poor VMM locking leading to subtle race conditions

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This commit is contained in:
Kamil Kowalczyk
2025-09-14 23:11:24 +02:00
parent 69e23a9ca3
commit 062e98d714
1 changed files with 4 additions and 4 deletions
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8
kernel/hal/x86_64/vmm.c
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@ -51,9 +51,7 @@ void hal_vmm_map_page(PgTable *pml4, uint64_t virtaddr, uint64_t physaddr, uint3
uint64_t *pml1 = hal_vmm_nexttable((uint64_t *)pml2, pi.pml2); uint64_t *pml1 = hal_vmm_nexttable((uint64_t *)pml2, pi.pml2);
uint64_t *pte = &pml1[pi.pml1]; uint64_t *pte = &pml1[pi.pml1];
spinlock_acquire(&spinlock);
*pte = (physaddr & ~0xFFF) | (flags & 0x7); *pte = (physaddr & ~0xFFF) | (flags & 0x7);
spinlock_release(&spinlock);
} }
void hal_vmm_unmap_page(PgTable *pml4, uint64_t virtaddr, uint64_t physaddr) { void hal_vmm_unmap_page(PgTable *pml4, uint64_t virtaddr, uint64_t physaddr) {
@ -64,9 +62,7 @@ void hal_vmm_unmap_page(PgTable *pml4, uint64_t virtaddr, uint64_t physaddr) {
uint64_t *pml1 = hal_vmm_nexttable((uint64_t *)pml2, pi.pml2); uint64_t *pml1 = hal_vmm_nexttable((uint64_t *)pml2, pi.pml2);
uint64_t *pte = &pml1[pi.pml1]; uint64_t *pte = &pml1[pi.pml1];
spinlock_acquire(&spinlock);
*pte &= ~HAL_PG_PRESENT; *pte &= ~HAL_PG_PRESENT;
spinlock_release(&spinlock);
} }
void hal_vmm_map_range(PgTable *cr3, void *virtstart, void *physstart, size_t size, uint32_t flags) { void hal_vmm_map_range(PgTable *cr3, void *virtstart, void *physstart, size_t size, uint32_t flags) {
@ -74,11 +70,13 @@ void hal_vmm_map_range(PgTable *cr3, void *virtstart, void *physstart, size_t si
return; return;
} }
spinlock_acquire(&spinlock);
uint8_t *vaddr = virtstart, *paddr = physstart; uint8_t *vaddr = virtstart, *paddr = physstart;
for (; vaddr <= ((uint8_t *)virtstart + size); vaddr += HAL_PAGE_SIZE, paddr += HAL_PAGE_SIZE) { for (; vaddr <= ((uint8_t *)virtstart + size); vaddr += HAL_PAGE_SIZE, paddr += HAL_PAGE_SIZE) {
hal_vmm_map_page(cr3, (uint64_t)vaddr, (uint64_t)paddr, flags); hal_vmm_map_page(cr3, (uint64_t)vaddr, (uint64_t)paddr, flags);
} }
spinlock_release(&spinlock);
} }
void hal_vmm_unmap_range(PgTable *cr3, void *virtstart, void *physstart, size_t size) { void hal_vmm_unmap_range(PgTable *cr3, void *virtstart, void *physstart, size_t size) {
@ -86,11 +84,13 @@ void hal_vmm_unmap_range(PgTable *cr3, void *virtstart, void *physstart, size_t
return; return;
} }
spinlock_acquire(&spinlock);
uint8_t *vaddr = virtstart, *paddr = physstart; uint8_t *vaddr = virtstart, *paddr = physstart;
for (; vaddr <= ((uint8_t *)virtstart + size); vaddr += HAL_PAGE_SIZE, paddr += HAL_PAGE_SIZE) { for (; vaddr <= ((uint8_t *)virtstart + size); vaddr += HAL_PAGE_SIZE, paddr += HAL_PAGE_SIZE) {
hal_vmm_unmap_page(cr3, (uint64_t)vaddr, (uint64_t)paddr); hal_vmm_unmap_page(cr3, (uint64_t)vaddr, (uint64_t)paddr);
} }
spinlock_release(&spinlock);
} }
void hal_vmm_map_kern(PgTable *cr3) { void hal_vmm_map_kern(PgTable *cr3) {