KVM: x86/mmu: Remove redundant root_hpa checks

The root_hpa checks below the top-level check in kvm_mmu_page_fault are
theoretically redundant since there is no longer a way for the root_hpa
to be reset during a page fault. The details of why are described in
commit ddce6208217c ("KVM: x86/mmu: Move root_hpa validity checks to top
of page fault handler")

__direct_map, kvm_tdp_mmu_map, and get_mmio_spte are all only reachable
through kvm_mmu_page_fault, therefore their root_hpa checks are
redundant.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20210617231948.2591431-5-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f1dd830..84d48a3 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2859,9 +2859,6 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
        gfn_t gfn = gpa >> PAGE_SHIFT;
        gfn_t base_gfn = gfn;
 
-       if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa)))
-               return RET_PF_RETRY;
-
        level = kvm_mmu_hugepage_adjust(vcpu, gfn, max_level, &pfn,
                                        huge_page_disallowed, &req_level);
 
@@ -3603,11 +3600,6 @@ static bool get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr, u64 *sptep)
        int root, leaf, level;
        bool reserved = false;
 
-       if (!VALID_PAGE(vcpu->arch.mmu->root_hpa)) {
-               *sptep = 0ull;
-               return reserved;
-       }
-
        if (is_tdp_mmu(vcpu->arch.mmu))
                leaf = kvm_tdp_mmu_get_walk(vcpu, addr, sptes, &root);
        else

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index d4c254d..caac4dd 100644 (file)
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -983,9 +983,6 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
        int level;
        int req_level;
 
-       if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa)))
-               return RET_PF_RETRY;
-
        level = kvm_mmu_hugepage_adjust(vcpu, gfn, max_level, &pfn,
                                        huge_page_disallowed, &req_level);