proxmox-mirrors/mirror_ubuntu-kernels
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_ubuntu-kernels.git synced 2026-01-03 00:42:28 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

KVM: arm64: Add a helper to tear down unlinked stage-2 subtrees

Browse Source 
A subsequent change to KVM will move the tear down of an unlinked
stage-2 subtree out of the critical path of the break-before-make
sequence.

Introduce a new helper for tearing down unlinked stage-2 subtrees.
Leverage the existing stage-2 free walkers to do so, with a deep call
into __kvm_pgtable_walk() as the subtree is no longer reachable from the
root.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221107215644.1895162-6-oliver.upton@linux.dev
This commit is contained in:
Oliver Upton 2022-11-07 21:56:35 +00:00 committed by Marc Zyngier
parent fa002e8e79
commit 8e94e1252c
2 changed files with 34 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/arm64/include/asm/kvm_pgtable.h
View File

@ -333,6 +333,17 @@ int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
*/
void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt);
/**
* kvm_pgtable_stage2_free_removed() - Free a removed stage-2 paging structure.
* @mm_ops: Memory management callbacks.
* @pgtable: Unlinked stage-2 paging structure to be freed.
* @level: Level of the stage-2 paging structure to be freed.
*
* The page-table is assumed to be unreachable by any hardware walkers prior to
* freeing and therefore no TLB invalidation is performed.
*/
void kvm_pgtable_stage2_free_removed(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, u32 level);
/**
* kvm_pgtable_stage2_map() - Install a mapping in a guest stage-2 page-table.
* @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*().

23
arch/arm64/kvm/hyp/pgtable.c
View File

@ -1203,3 +1203,26 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_sz);
pgt->pgd = NULL;
}
void kvm_pgtable_stage2_free_removed(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, u32 level)
{
kvm_pte_t *ptep = (kvm_pte_t *)pgtable;
struct kvm_pgtable_walker walker = {
.cb = stage2_free_walker,
.flags = KVM_PGTABLE_WALK_LEAF |
KVM_PGTABLE_WALK_TABLE_POST,
};
struct kvm_pgtable_walk_data data = {
.walker = &walker,
/*
* At this point the IPA really doesn't matter, as the page
* table being traversed has already been removed from the stage
* 2. Set an appropriate range to cover the entire page table.
*/
.addr = 0,
.end = kvm_granule_size(level),
};
WARN_ON(__kvm_pgtable_walk(&data, mm_ops, ptep, level));
}