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KVM: arm64: Make leaf->leaf PTE changes parallel-aware

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Convert stage2_map_walker_try_leaf() to use the new break-before-make
helpers, thereby making the handler parallel-aware. As before, avoid the
break-before-make if recreating the existing mapping. Additionally,
retry execution if another vCPU thread is modifying the same PTE.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221107215934.1895478-1-oliver.upton@linux.dev
This commit is contained in:
Oliver Upton
2022-11-07 21:59:34 +00:00
committed by Marc Zyngier
parent 0ab12f3574
commit 946fbfdf33
1 changed files with 12 additions and 14 deletions
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arch/arm64/kvm/hyp/pgtable.c
+12 -14
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@@ -804,18 +804,17 @@ static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
else
new = kvm_init_invalid_leaf_owner(data->owner_id);
if (stage2_pte_is_counted(ctx->old)) {
/*
* Skip updating the PTE if we are trying to recreate the exact
* same mapping or only change the access permissions. Instead,
* the vCPU will exit one more time from guest if still needed
* and then go through the path of relaxing permissions.
*/
if (!stage2_pte_needs_update(ctx->old, new))
return -EAGAIN;
/*
* Skip updating the PTE if we are trying to recreate the exact
* same mapping or only change the access permissions. Instead,
* the vCPU will exit one more time from guest if still needed
* and then go through the path of relaxing permissions.
*/
if (!stage2_pte_needs_update(ctx->old, new))
return -EAGAIN;
stage2_put_pte(ctx, data->mmu, mm_ops);
}
if (!stage2_try_break_pte(ctx, data->mmu))
return -EAGAIN;
/* Perform CMOs before installation of the guest stage-2 PTE */
if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new))
@@ -825,9 +824,8 @@ static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
if (mm_ops->icache_inval_pou && stage2_pte_executable(new))
mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
smp_store_release(ctx->ptep, new);
if (stage2_pte_is_counted(new))
mm_ops->get_page(ctx->ptep);
stage2_make_pte(ctx, new);
if (kvm_phys_is_valid(phys))
data->phys += granule;
return 0;