On Wed, Feb 07, 2024 at 09:26:27AM -0800, Xin Li wrote:
>Add FRED MSRs to the valid passthrough MSR list and set FRED MSRs intercept
>based on FRED enumeration.
>
>Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
>Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
Reviewed-by: Chao Gao <chao.gao@xxxxxxxxx>
two nits below.
>---
>
>Change since v1:
>* Enable FRED MSRs intercept if FRED is no longer enumerated in CPUID
> (Chao Gao).
>---
> arch/x86/kvm/vmx/vmx.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
>diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
>index 34b6676f60d8..d58ed2d3d379 100644
>--- a/arch/x86/kvm/vmx/vmx.c
>+++ b/arch/x86/kvm/vmx/vmx.c
>@@ -693,6 +693,9 @@ static bool is_valid_passthrough_msr(u32 msr)
> case MSR_LBR_CORE_TO ... MSR_LBR_CORE_TO + 8:
> /* LBR MSRs. These are handled in vmx_update_intercept_for_lbr_msrs() */
> return true;
>+ case MSR_IA32_FRED_RSP0 ... MSR_IA32_FRED_CONFIG:
>+ /* FRED MSRs should be passthrough to FRED guests only */
This comment sounds weird. It sounds like the code will be something like:
if guest supports FRED
return true
else
return false
how about "FRED MSRs are pass-thru'd to guests which enumerate FRED"?
Or to align with above comment for LBR MSRs, just say
/* FRED MSRs. These are handled in vmx_vcpu_config_fred_after_set_cpuid() */
>+ return true;
> }
>
> r = possible_passthrough_msr_slot(msr) != -ENOENT;
>@@ -7774,10 +7777,12 @@ static void update_intel_pt_cfg(struct kvm_vcpu *vcpu)
> static void vmx_vcpu_config_fred_after_set_cpuid(struct kvm_vcpu *vcpu)
> {
> struct vcpu_vmx *vmx = to_vmx(vcpu);
>+ bool fred_enumerated;
>
> kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_FRED);
>+ fred_enumerated = guest_can_use(vcpu, X86_FEATURE_FRED);
>
>- if (guest_can_use(vcpu, X86_FEATURE_FRED)) {
>+ if (fred_enumerated) {
> vm_entry_controls_setbit(vmx, VM_ENTRY_LOAD_IA32_FRED);
> secondary_vm_exit_controls_setbit(vmx,
> SECONDARY_VM_EXIT_SAVE_IA32_FRED |
>@@ -7788,6 +7793,16 @@ static void vmx_vcpu_config_fred_after_set_cpuid(struct kvm_vcpu *vcpu)
> SECONDARY_VM_EXIT_SAVE_IA32_FRED |
> SECONDARY_VM_EXIT_LOAD_IA32_FRED);
> }
>+
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP0, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP1, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP2, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP3, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_STKLVLS, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_SSP1, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_SSP2, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_SSP3, MSR_TYPE_RW, !fred_enumerated);
>+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_CONFIG, MSR_TYPE_RW, !fred_enumerated);
Use a for-loop here? e.g.,
for (i = MSR_IA32_FRED_RSP0; i <= MSR_IA32_FRED_CONFIG; i++)
> }
>
> static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
>--
>2.43.0
>
>
