#ifdef CONFIG_X86_64 MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
- MSR_IA32_FRED_RSP0, MSR_IA32_FRED_RSP1, MSR_IA32_FRED_RSP2,
- MSR_IA32_FRED_RSP3, MSR_IA32_FRED_STKLVLS, MSR_IA32_FRED_SSP1,
- MSR_IA32_FRED_SSP2, MSR_IA32_FRED_SSP3, MSR_IA32_FRED_CONFIG,
Need to handle the case where FRED MSRs are valid but KVM cannot virtualize FRED, see kvm_probe_msr_to_save().
Will take care of it, thanks for reminding.
#endif MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA, MSR_IA32_FEAT_CTL, MSR_IA32_BNDCFGS, MSR_TSC_AUX, @@ -1890,6
+1893,16
@@ static int __kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data,
data = (u32)data; break;
- case MSR_IA32_FRED_RSP0 ... MSR_IA32_FRED_CONFIG:
if (host_initiated || guest_cpuid_has(vcpu, X86_FEATURE_FRED))break;Nothing guarantees FRED MSRs/VMCS fields exist on the hardware here. Probably use guest_cpu_cap_has()*.
Ah, my bad!
*: https://lore.kernel.org/kvm/20231110235528.1561679-1-seanjc@google.com
/** Inject #GP upon FRED MSRs accesses from a non-FRED guest to* make sure no malicious guest can write to FRED MSRs thus to* corrupt host FRED MSRs.*/I think injecting #GP here is simply because KVM should emulate hardware behavior. To me, preventing guest from corrupting FRED MSRs is at most a byproduct. I prefer to drop the comment.
From security POV, this is important to mention.