On certain CPUs, Linux guests expect HWCR.TscFreqSel[bit 24] to be
set. If it isn't set, they complain:
[Firmware Bug]: TSC doesn't count with P0 frequency!
Allow userspace to set this bit in the virtual HWCR to eliminate the
above complaint.
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1a323cae219c..86a1bb0e6227 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3700,8 +3700,12 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
data &= ~(u64)0x100; /* ignore ignne emulation enable */
data &= ~(u64)0x8; /* ignore TLB cache disable */
- /* Handle McStatusWrEn */
- if (data & ~BIT_ULL(18)) {
+ /*
+ * Allow McStatusWrEn and TscFreqSel. (Linux guests from v3.2
+ * through at least v6.6 whine if TscFreqSel is clear,
+ * depending on F/M/S.
+ */
+ if (data & ~(BIT_ULL(18) | BIT_ULL(24))) {
kvm_pr_unimpl_wrmsr(vcpu, msr, data);
return 1;
}
--
2.42.0.582.g8ccd20d70d-goog
