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x86/kvm/mmu: reset MMU context when 32-bit guest switches PAE

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Commit 47c42e6b41 ("KVM: x86: fix handling of role.cr4_pae and rename it
to 'gpte_size'") introduced a regression: 32-bit PAE guests stopped
working. The issue appears to be: when guest switches (enables) PAE we need
to re-initialize MMU context (set context->root_level, do
reset_rsvds_bits_mask(), ...) but init_kvm_tdp_mmu() doesn't do that
because we threw away is_pae(vcpu) flag from mmu role. Restore it to
kvm_mmu_extended_role (as we now don't need it in base role) to fix
the issue.

Fixes: 47c42e6b41 ("KVM: x86: fix handling of role.cr4_pae and rename it to 'gpte_size'")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2019-04-30 19:33:26 +02:00 committed by Paolo Bonzini
parent 8764ed55c9
commit 0699c64a4b
2 changed files with 2 additions and 0 deletions
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1
arch/x86/include/asm/kvm_host.h
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@ -295,6 +295,7 @@ union kvm_mmu_extended_role {
unsigned int valid:1;
unsigned int execonly:1;
unsigned int cr0_pg:1;
unsigned int cr4_pae:1;
unsigned int cr4_pse:1;
unsigned int cr4_pke:1;
unsigned int cr4_smap:1;

1
arch/x86/kvm/mmu.c
View file

@ -4781,6 +4781,7 @@ static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu)
union kvm_mmu_extended_role ext = {0};
ext.cr0_pg = !!is_paging(vcpu);
ext.cr4_pae = !!is_pae(vcpu);
ext.cr4_smep = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
ext.cr4_smap = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMAP);
ext.cr4_pse = !!is_pse(vcpu);