Messages in this thread | | | Subject | Re: [RFC 2/7] KVM: VMX: Expose IA32_PKRS MSR | From | Paolo Bonzini <> | Date | Tue, 26 Jan 2021 19:01:55 +0100 |
| |
On 07/08/20 10:48, Chenyi Qiang wrote: > +{ > + struct vcpu_vmx *vmx = to_vmx(vcpu); > + unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap; > + bool pks_supported = guest_cpuid_has(vcpu, X86_FEATURE_PKS); > + > + /* > + * set intercept for PKRS when the guest doesn't support pks > + */ > + vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_PKRS, MSR_TYPE_RW, !pks_supported); > + > + if (pks_supported) { > + vm_entry_controls_setbit(vmx, VM_ENTRY_LOAD_IA32_PKRS); > + vm_exit_controls_setbit(vmx, VM_EXIT_LOAD_IA32_PKRS); > + } else { > + vm_entry_controls_clearbit(vmx, VM_ENTRY_LOAD_IA32_PKRS); > + vm_exit_controls_clearbit(vmx, VM_EXIT_LOAD_IA32_PKRS); > + }
Is the guest expected to do a lot of reads/writes to the MSR (e.g. at every context switch)?
Even if this is the case, the MSR intercepts and the entry/exit controls should only be done if CR4.PKS=1. If the guest does not use PKS, KVM should behave as if these patches did not exist.
Paolo
| |