diff options
| author | Sean Christopherson <seanjc@google.com> | 2024-08-30 17:15:36 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-09-09 20:16:35 -0700 |
| commit | d859b16161c81ee929b7b02a85227b8e3250bc97 (patch) | |
| tree | 39a92f6057f87e96d4fb1f2c960164b7539cea95 /arch/x86/kvm | |
| parent | 6b3dcabc10911711eba15816d808e2a18f130406 (diff) | |
KVM: x86/mmu: Detect if unprotect will do anything based on invalid_list
Explicitly query the list of to-be-zapped shadow pages when checking to
see if unprotecting a gfn for retry has succeeded, i.e. if KVM should
retry the faulting instruction.
Add a comment to explain why the list needs to be checked before zapping,
which is the primary motivation for this change.
No functional change intended.
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20240831001538.336683-22-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 29305403f956..ebbdc979a069 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2721,12 +2721,15 @@ bool __kvm_mmu_unprotect_gfn_and_retry(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, goto out; } - r = false; write_lock(&kvm->mmu_lock); - for_each_gfn_valid_sp_with_gptes(kvm, sp, gpa_to_gfn(gpa)) { - r = true; + for_each_gfn_valid_sp_with_gptes(kvm, sp, gpa_to_gfn(gpa)) kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); - } + + /* + * Snapshot the result before zapping, as zapping will remove all list + * entries, i.e. checking the list later would yield a false negative. + */ + r = !list_empty(&invalid_list); kvm_mmu_commit_zap_page(kvm, &invalid_list); write_unlock(&kvm->mmu_lock); |