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| author | Sean Christopherson <seanjc@google.com> | 2023-07-29 03:47:15 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-08-31 20:48:43 +0300 |
| commit | 58da926caad9c6ecba70202a3775f2fd9b476cfc (patch) | |
| tree | f059eb9dc027c93911cf5e782c2e0134811cc8fe /arch | |
| parent | 242a6dd8daddbc718a3ad585ce4dce042c13e208 (diff) | |
| download | linux-58da926caad9c6ecba70202a3775f2fd9b476cfc.tar.xz | |
KVM: x86/mmu: Cleanup sanity check of SPTEs at SP free
Massage the error message for the sanity check on SPTEs when freeing a
shadow page to be more verbose, and to print out all shadow-present SPTEs,
not just the first SPTE encountered. Printing all SPTEs can be quite
valuable for debug, e.g. highlights whether the leak is a one-off or
widepsread, or possibly the result of memory corruption (something else
in the kernel stomping on KVM's SPTEs).
Opportunistically move the MMU_WARN_ON() into the helper itself, which
will allow a future cleanup to use BUILD_BUG_ON_INVALID() as the stub for
MMU_WARN_ON(). BUILD_BUG_ON_INVALID() works as intended and results in
the compiler complaining about is_empty_shadow_page() not being declared.
Link: https://lore.kernel.org/r/20230729004722.1056172-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 3749ccdef6ce..cb3adaa69350 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1689,21 +1689,19 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) return young; } -#ifdef MMU_DEBUG -static int is_empty_shadow_page(u64 *spt) +static void kvm_mmu_check_sptes_at_free(struct kvm_mmu_page *sp) { +#ifdef MMU_DEBUG int i; for (i = 0; i < SPTE_ENT_PER_PAGE; i++) { - if (is_shadow_present_pte(spt[i])) { - printk(KERN_ERR "%s: %p %llx\n", __func__, - &spt[i], spt[i]); - return 0; - } + if (MMU_WARN_ON(is_shadow_present_pte(sp->spt[i]))) + pr_err_ratelimited("SPTE %llx (@ %p) for gfn %llx shadow-present at free", + sp->spt[i], &sp->spt[i], + kvm_mmu_page_get_gfn(sp, i)); } - return 1; -} #endif +} /* * This value is the sum of all of the kvm instances's @@ -1731,7 +1729,8 @@ static void kvm_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp) static void kvm_mmu_free_shadow_page(struct kvm_mmu_page *sp) { - MMU_WARN_ON(!is_empty_shadow_page(sp->spt)); + kvm_mmu_check_sptes_at_free(sp); + hlist_del(&sp->hash_link); list_del(&sp->link); free_page((unsigned long)sp->spt); |