[SRU Bionic] Revert "KVM: x86: Manually calculate reserved bits when loading PDPTRS"

[Po-Hsu Lin]

I think this one can be used:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1851709

On Tue, Nov 12, 2019 at 12:13 PM Khaled Elmously
<khalid.elmously at canonical.com> wrote:
>
> Was there a bug link for this regression?
>
>
> On 2019-11-11 19:24:32 , Thadeu Lima de Souza Cascardo wrote:
> > This reverts commit c5d574d63996442c80e886c60278a790230f4d2b.
> >
> > This commit has caused failure to launch 64-bit linux VMs when kvm-intel
> > ept module parameter is off. It is off by default on old Intel CPUs.
> >
> > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
> > ---
> >  arch/x86/kvm/x86.c | 11 +++--------
> >  1 file changed, 3 insertions(+), 8 deletions(-)
> >
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index ddbd7578ae25..d59095ab1f1c 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -566,14 +566,8 @@ static int kvm_read_nested_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
> >                                      data, offset, len, access);
> >  }
> >
> > -static inline u64 pdptr_rsvd_bits(struct kvm_vcpu *vcpu)
> > -{
> > -     return rsvd_bits(cpuid_maxphyaddr(vcpu), 63) | rsvd_bits(5, 8) |
> > -            rsvd_bits(1, 2);
> > -}
> > -
> >  /*
> > - * Load the pae pdptrs.  Return 1 if they are all valid, 0 otherwise.
> > + * Load the pae pdptrs.  Return true is they are all valid.
> >   */
> >  int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
> >  {
> > @@ -592,7 +586,8 @@ int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
> >       }
> >       for (i = 0; i < ARRAY_SIZE(pdpte); ++i) {
> >               if ((pdpte[i] & PT_PRESENT_MASK) &&
> > -                 (pdpte[i] & pdptr_rsvd_bits(vcpu))) {
> > +                 (pdpte[i] &
> > +                  vcpu->arch.mmu.guest_rsvd_check.rsvd_bits_mask[0][2])) {
> >                       ret = 0;
> >                       goto out;
> >               }
> > --
> > 2.20.1
> >
> >
> > --
> > kernel-team mailing list
> > kernel-team at lists.ubuntu.com
> > https://lists.ubuntu.com/mailman/listinfo/kernel-team
>
> --
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