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KVM: x86/mmu: load new PGD after the shadow MMU is initialized

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Now that __kvm_mmu_new_pgd does not look at the MMU's root_level and
shadow_root_level anymore, pull the PGD load after the initialization of
the shadow MMUs.

Besides being more intuitive, this enables future simplifications
and optimizations because it's not necessary anymore to compute the
role outside kvm_init_mmu.  In particular, kvm_mmu_reset_context was not
attempting to use a cached PGD to avoid having to figure out the new role.
With this change, it could follow what nested_{vmx,svm}_load_cr3 are doing,
and avoid unloading all the cached roots.

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2022-02-04 04:12:31 -05:00
parent 5499ea73e7
commit 3cffc89d9d
3 changed files with 25 additions and 28 deletions
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41
arch/x86/kvm/mmu/mmu.c
View File

@ -4881,9 +4881,8 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
new_role = kvm_calc_shadow_npt_root_page_role(vcpu, &regs);
__kvm_mmu_new_pgd(vcpu, nested_cr3, new_role.base);
shadow_mmu_init_context(vcpu, context, &regs, new_role);
__kvm_mmu_new_pgd(vcpu, nested_cr3, new_role.base);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
@ -4921,27 +4920,25 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
execonly, level);
if (new_role.as_u64 != context->mmu_role.as_u64) {
context->mmu_role.as_u64 = new_role.as_u64;
context->shadow_root_level = level;
context->ept_ad = accessed_dirty;
context->page_fault = ept_page_fault;
context->gva_to_gpa = ept_gva_to_gpa;
context->sync_page = ept_sync_page;
context->invlpg = ept_invlpg;
context->root_level = level;
context->direct_map = false;
update_permission_bitmask(context, true);
context->pkru_mask = 0;
reset_rsvds_bits_mask_ept(vcpu, context, execonly, huge_page_level);
reset_ept_shadow_zero_bits_mask(context, execonly);
}
__kvm_mmu_new_pgd(vcpu, new_eptp, new_role.base);
if (new_role.as_u64 == context->mmu_role.as_u64)
return;
context->mmu_role.as_u64 = new_role.as_u64;
context->shadow_root_level = level;
context->ept_ad = accessed_dirty;
context->page_fault = ept_page_fault;
context->gva_to_gpa = ept_gva_to_gpa;
context->sync_page = ept_sync_page;
context->invlpg = ept_invlpg;
context->root_level = level;
context->direct_map = false;
update_permission_bitmask(context, true);
context->pkru_mask = 0;
reset_rsvds_bits_mask_ept(vcpu, context, execonly, huge_page_level);
reset_ept_shadow_zero_bits_mask(context, execonly);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);

6
arch/x86/kvm/svm/nested.c
View File

@ -492,14 +492,14 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
CC(!load_pdptrs(vcpu, cr3)))
return -EINVAL;
if (!nested_npt)
kvm_mmu_new_pgd(vcpu, cr3);
vcpu->arch.cr3 = cr3;
/* Re-initialize the MMU, e.g. to pick up CR4 MMU role changes. */
kvm_init_mmu(vcpu);
if (!nested_npt)
kvm_mmu_new_pgd(vcpu, cr3);
return 0;
}

6
arch/x86/kvm/vmx/nested.c
View File

@ -1126,15 +1126,15 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
return -EINVAL;
}
if (!nested_ept)
kvm_mmu_new_pgd(vcpu, cr3);
vcpu->arch.cr3 = cr3;
kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
/* Re-initialize the MMU, e.g. to pick up CR4 MMU role changes. */
kvm_init_mmu(vcpu);
if (!nested_ept)
kvm_mmu_new_pgd(vcpu, cr3);
return 0;
}