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

[Tyler Hicks]

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>

Acked-by: Tyler Hicks <tyhicks at canonical.com>

Thanks!

Tyler

> ---
>  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
> 
> 
> -- 
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