Messages in this thread | | | Subject | Re: [PATCH v1 1/4] KVM: MMU: check guest CR3 reserved bits based on its physical address width. | From | Yu Zhang <> | Date | Mon, 14 Aug 2017 19:39:01 +0800 |
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On 8/14/2017 3:36 PM, Paolo Bonzini wrote: > On 12/08/2017 15:35, Yu Zhang wrote: >> + ctxt->ops->get_cpuid(ctxt, &eax, NULL, NULL, NULL); >> + maxphyaddr = eax * 0xff; > This is "&", not "*". You can also use rsvd_bits here.
Oops. Sorry for the typo. :-)
>> + rsvd = (~((1UL << maxphyaddr) - 1)) & >> + ~CR3_PCID_INVD; >> + } >> >> if (new_val & rsvd) >> return emulate_gp(ctxt, 0); >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index e40a779..d9100c4 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -813,10 +813,10 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) >> return 0; >> } >> >> - if (is_long_mode(vcpu)) { >> - if (cr3 & CR3_L_MODE_RESERVED_BITS) >> - return 1; >> - } else if (is_pae(vcpu) && is_paging(vcpu) && >> + if (is_long_mode(vcpu) && >> + (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63))) >> + return 1; > 62 is a little better, since 63 is the PCID invalidate bit.
Got it. Both kvm_set_cr3() and check_cr_write() should use rsvd_bits(maxphyaddr, 62) .
Thanks Yu
> Paolo > >> + else if (is_pae(vcpu) && is_paging(vcpu) && >> !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) >> return 1; >> >
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