leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

KVM: x86/mmu: Remove redundant root_hpa checks

Browse Source 
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 ddce620821 ("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>
This commit is contained in:
David Matlack 2021-06-17 23:19:48 +00:00 committed by Paolo Bonzini
parent 63c0cac938
commit 0485cf8dbe
2 changed files with 0 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/x86/kvm/mmu/mmu.c
View File

@ -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

3
arch/x86/kvm/mmu/tdp_mmu.c
View File

@ -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);