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

[Thadeu Lima de Souza Cascardo]

On Tue, Nov 12, 2019 at 12:17:36PM +0800, Po-Hsu Lin wrote:
> I think this one can be used:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1851709

Sorry, I meant to use the other one, which has been marked as duplicated of this one.

LP: #1851709 is good enough. Notice that this has been tested to fix the issue.

I will send again including the fix for disco.

Cascardo.


> 
> 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
> >
> > --
> > kernel-team mailing list
> > kernel-team at lists.ubuntu.com
> > https://lists.ubuntu.com/mailman/listinfo/kernel-team