diff options
author | Kai Huang <kai.huang@intel.com> | 2022-07-28 15:04:52 +1200 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-07-28 14:02:07 -0400 |
commit | 7edc3a68038ab151a8791ddb6217755a5e4a5809 (patch) | |
tree | 61bb11f29af7cd85bd28d1cb593a585b7f80979f | |
parent | 6fac42f127b8e8464b8c13036dfed825981881d9 (diff) | |
download | linux-7edc3a68038ab151a8791ddb6217755a5e4a5809.tar.bz2 |
KVM, x86/mmu: Fix the comment around kvm_tdp_mmu_zap_leafs()
Now kvm_tdp_mmu_zap_leafs() only zaps leaf SPTEs but not any non-root
pages within that GFN range anymore, so the comment around it isn't
right.
Fix it by shifting the comment from tdp_mmu_zap_leafs() instead of
duplicating it, as tdp_mmu_zap_leafs() is static and is only called by
kvm_tdp_mmu_zap_leafs().
Opportunistically tweak the blurb about SPTEs being cleared to (a) say
"zapped" instead of "cleared" because "cleared" will be wrong if/when
KVM allows a non-zero value for non-present SPTE (i.e. for Intel TDX),
and (b) to clarify that a flush is needed if and only if a SPTE has been
zapped since MMU lock was last acquired.
Fixes: f47e5bbbc92f ("KVM: x86/mmu: Zap only TDP MMU leafs in zap range and mmu_notifier unmap")
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Message-Id: <20220728030452.484261-1-kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 40ccb5fba870..bf2ccf9debca 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -924,9 +924,6 @@ bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) } /* - * Zap leafs SPTEs for the range of gfns, [start, end). Returns true if SPTEs - * have been cleared and a TLB flush is needed before releasing the MMU lock. - * * If can_yield is true, will release the MMU lock and reschedule if the * scheduler needs the CPU or there is contention on the MMU lock. If this * function cannot yield, it will not release the MMU lock or reschedule and @@ -969,10 +966,9 @@ static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root, } /* - * Tears down the mappings for the range of gfns, [start, end), and frees the - * non-root pages mapping GFNs strictly within that range. Returns true if - * SPTEs have been cleared and a TLB flush is needed before releasing the - * MMU lock. + * Zap leaf SPTEs for the range of gfns, [start, end), for all roots. Returns + * true if a TLB flush is needed before releasing the MMU lock, i.e. if one or + * more SPTEs were zapped since the MMU lock was last acquired. */ bool kvm_tdp_mmu_zap_leafs(struct kvm *kvm, int as_id, gfn_t start, gfn_t end, bool can_yield, bool flush) |