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 | Tue, 15 Aug 2017 15:50:36 +0800 |
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On 8/15/2017 12:40 AM, Paolo Bonzini wrote: > On 14/08/2017 18:13, Jim Mattson wrote: >>> ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); >>> - if (efer & EFER_LMA) >>> - rsvd = CR3_L_MODE_RESERVED_BITS & ~CR3_PCID_INVD; >>> + if (efer & EFER_LMA) { >>> + u64 maxphyaddr; >>> + u32 eax = 0x80000008; >>> + >>> + ctxt->ops->get_cpuid(ctxt, &eax, NULL, NULL, NULL); >>> + maxphyaddr = eax * 0xff; >> What if leaf 0x80000008 is not defined? > I noticed this too, but I thought it was mitigated by being under > EFER_LMA. Unfortunately, kvm_set_efer doesn't check > guest_cpuid_has_longmode, so I guess you do have to test leaf 0x80000000 > first. Alternatively: > > 1) kvm_cpuid could return false if it's falling back to > check_cpuid_limit, and emulator_get_cpuid can then be changed to return bool > > 2) kvm_cpuid and emulator_get_cpuid could gain a new argument to disable > the check_cpuid_limit fallback. > > Yu, would you like to implement the latter?
Thanks for pointing this out, Jim & Paolo. The latter choice sounds better to me. :-) I'd like to implement this in a separate patch in next version patch set.
Yu > Paolo >
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