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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-07-15 20:41:20 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-07-30 18:17:16 -0400 |
| commit | d468d94b7bafa7a2dd9bc72e5f7868469be3f7c4 (patch) | |
| tree | 5bb406f69834e69eedde8e263eaa67757d76c611 /arch/x86/kvm/mmu/mmu.c | |
| parent | f83a4a6932f002701db19f968938ada1289f5e3c (diff) | |
| download | lwn-d468d94b7bafa7a2dd9bc72e5f7868469be3f7c4.tar.gz lwn-d468d94b7bafa7a2dd9bc72e5f7868469be3f7c4.zip | |
KVM: x86: Dynamically calculate TDP level from max level and MAXPHYADDR
Calculate the desired TDP level on the fly using the max TDP level and
MAXPHYADDR instead of doing the same when CPUID is updated. This avoids
the hidden dependency on cpuid_maxphyaddr() in vmx_get_tdp_level() and
also standardizes the "use 5-level paging iff MAXPHYADDR > 48" behavior
across x86.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200716034122.5998-8-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 0fb033ce6cc5..559b4b92b5e2 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4846,13 +4846,22 @@ static union kvm_mmu_role kvm_calc_mmu_role_common(struct kvm_vcpu *vcpu, return role; } +static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu) +{ + /* Use 5-level TDP if and only if it's useful/necessary. */ + if (vcpu->arch.max_tdp_level == 5 && cpuid_maxphyaddr(vcpu) <= 48) + return 4; + + return vcpu->arch.max_tdp_level; +} + static union kvm_mmu_role kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu, bool base_only) { union kvm_mmu_role role = kvm_calc_mmu_role_common(vcpu, base_only); role.base.ad_disabled = (shadow_accessed_mask == 0); - role.base.level = vcpu->arch.tdp_level; + role.base.level = kvm_mmu_get_tdp_level(vcpu); role.base.direct = true; role.base.gpte_is_8_bytes = true; @@ -4873,7 +4882,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu) context->sync_page = nonpaging_sync_page; context->invlpg = NULL; context->update_pte = nonpaging_update_pte; - context->shadow_root_level = vcpu->arch.tdp_level; + context->shadow_root_level = kvm_mmu_get_tdp_level(vcpu); context->direct_map = true; context->get_guest_pgd = get_cr3; context->get_pdptr = kvm_pdptr_read; @@ -4973,7 +4982,7 @@ kvm_calc_shadow_npt_root_page_role(struct kvm_vcpu *vcpu) kvm_calc_shadow_root_page_role_common(vcpu, false); role.base.direct = false; - role.base.level = vcpu->arch.tdp_level; + role.base.level = kvm_mmu_get_tdp_level(vcpu); return role; } @@ -5683,7 +5692,7 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) * SVM's 32-bit NPT support, TDP paging doesn't use PAE paging and can * skip allocating the PDP table. */ - if (tdp_enabled && vcpu->arch.tdp_level > PT32E_ROOT_LEVEL) + if (tdp_enabled && kvm_mmu_get_tdp_level(vcpu) > PT32E_ROOT_LEVEL) return 0; page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_DMA32); |