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kvm: x86: Read PDPTEs on CR0.CD and CR0.NW changes

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According to the SDM, when PAE paging would be in use following a
MOV-to-CR0 that modifies any of CR0.CD, CR0.NW, or CR0.PG, then the
PDPTEs are loaded from the address in CR3. Previously, kvm only loaded
the PDPTEs when PAE paging would be in use following a MOV-to-CR0 that
modified CR0.PG.

Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Message-Id: <20200707223630.336700-1-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jim Mattson 2020-07-07 15:36:30 -07:00 committed by Paolo Bonzini
parent 9a3c05e658
commit d42e3fae6f
1 changed files with 5 additions and 4 deletions
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9
arch/x86/kvm/x86.c
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@ -798,6 +798,7 @@ EXPORT_SYMBOL_GPL(pdptrs_changed);
int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
unsigned long old_cr0 = kvm_read_cr0(vcpu);
unsigned long pdptr_bits = X86_CR0_CD | X86_CR0_NW | X86_CR0_PG;
unsigned long update_bits = X86_CR0_PG | X86_CR0_WP;
cr0 |= X86_CR0_ET;
@ -815,9 +816,9 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE))
return 1;
if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
if (cr0 & X86_CR0_PG) {
#ifdef CONFIG_X86_64
if ((vcpu->arch.efer & EFER_LME)) {
if (!is_paging(vcpu) && (vcpu->arch.efer & EFER_LME)) {
int cs_db, cs_l;
if (!is_pae(vcpu))
@ -827,8 +828,8 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
return 1;
} else
#endif
if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu,
kvm_read_cr3(vcpu)))
if (is_pae(vcpu) && ((cr0 ^ old_cr0) & pdptr_bits) &&
!load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu)))
return 1;
}