On 04/05/2018 20:37, Junaid Shahid wrote:
> If the PCIDE bit is not set in CR4, then the MSb of CR3 is a reserved
> bit. If the guest tries to set it, that should cause a #GP fault. So
> mask out the bit only when the PCIDE bit is set.
>
> Signed-off-by: Junaid Shahid <junaids@xxxxxxxxxx>
> ---
> arch/x86/kvm/x86.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 847ce7f0a2c8..5a19d220a9c3 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -845,7 +845,10 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
> unsigned long old_cr3 = kvm_read_cr3(vcpu);
>
> #ifdef CONFIG_X86_64
> - cr3 &= ~CR3_PCID_INVD;
> + bool pcid_enabled = kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE);
> +
> + if (pcid_enabled)
> + cr3 &= ~CR3_PCID_INVD;
> #endif
>
> if (cr3 == old_cr3 && !pdptrs_changed(vcpu)) {
>
Queued, thanks.
Paolo
