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vm_iommu_map()/unmap(): stop transiently wiring already wired pages

Browse source 
Namely, switch from vm_fault_quick_hold() to pmap_extract() KPI to
translate gpa to hpa. Assert that the looked up hpa belongs to the wired
page, as it should be for the VM which is configured for pass-throu
(this is theoretically a restriction that could be removed on newer
DMARs).

Noted by:	alc
Reviewed by:	alc, jhb, markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D43140
This commit is contained in:
Konstantin Belousov 2023-12-21 02:12:37 +02:00
parent 3abc72f871
commit 671a00491d
1 changed files with 25 additions and 14 deletions
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39
sys/amd64/vmm/vmm.c
View file

@ -1041,9 +1041,10 @@ vm_iommu_map(struct vm *vm)
{
vm_paddr_t gpa, hpa;
struct mem_map *mm;
void *vp, *cookie;
int i;
sx_assert(&vm->mem_segs_lock, SX_LOCKED);
for (i = 0; i < VM_MAX_MEMMAPS; i++) {
mm = &vm->mem_maps[i];
if (!sysmem_mapping(vm, mm))
@ -1057,13 +1058,24 @@ vm_iommu_map(struct vm *vm)
mm->flags |= VM_MEMMAP_F_IOMMU;
for (gpa = mm->gpa; gpa < mm->gpa + mm->len; gpa += PAGE_SIZE) {
vp = vm_gpa_hold_global(vm, gpa, PAGE_SIZE,
VM_PROT_WRITE, &cookie);
KASSERT(vp != NULL, ("vm(%s) could not map gpa %#lx",
vm_name(vm), gpa));
vm_gpa_release(cookie);
hpa = pmap_extract(vmspace_pmap(vm->vmspace), gpa);
/*
* All mappings in the vmm vmspace must be
* present since they are managed by vmm in this way.
* Because we are in pass-through mode, the
* mappings must also be wired. This implies
* that all pages must be mapped and wired,
* allowing to use pmap_extract() and avoiding the
* need to use vm_gpa_hold_global().
*
* This could change if/when we start
* supporting page faults on IOMMU maps.
*/
KASSERT(vm_page_wired(PHYS_TO_VM_PAGE(hpa)),
("vm_iommu_map: vm %p gpa %jx hpa %jx not wired",
vm, (uintmax_t)gpa, (uintmax_t)hpa));
hpa = DMAP_TO_PHYS((uintptr_t)vp);
iommu_create_mapping(vm->iommu, gpa, hpa, PAGE_SIZE);
}
}
@ -1076,9 +1088,10 @@ vm_iommu_unmap(struct vm *vm)
{
vm_paddr_t gpa;
struct mem_map *mm;
void *vp, *cookie;
int i;
sx_assert(&vm->mem_segs_lock, SX_LOCKED);
for (i = 0; i < VM_MAX_MEMMAPS; i++) {
mm = &vm->mem_maps[i];
if (!sysmem_mapping(vm, mm))
@ -1092,12 +1105,10 @@ vm_iommu_unmap(struct vm *vm)
mm->gpa, mm->len, mm->flags));
for (gpa = mm->gpa; gpa < mm->gpa + mm->len; gpa += PAGE_SIZE) {
vp = vm_gpa_hold_global(vm, gpa, PAGE_SIZE,
VM_PROT_WRITE, &cookie);
KASSERT(vp != NULL, ("vm(%s) could not map gpa %#lx",
vm_name(vm), gpa));
vm_gpa_release(cookie);
KASSERT(vm_page_wired(PHYS_TO_VM_PAGE(pmap_extract(
vmspace_pmap(vm->vmspace), gpa))),
("vm_iommu_unmap: vm %p gpa %jx not wired",
vm, (uintmax_t)gpa));
iommu_remove_mapping(vm->iommu, gpa, PAGE_SIZE);
}
}