Since below KVM commit, KVM hided BTS as it's not supported yet.
b9181c8ef356 ("KVM: x86/pmu: Avoid exposing Intel BTS feature")
After below KVM commit, it gave control of MSR_IA32_MISC_ENABLES to userspace.
9fc222967a39 ("KVM: x86: Give host userspace full control of
MSR_IA32_MISC_ENABLES")
So qemu takes the responsibility to hide BTS.
Without fix, we get below warning in guest kernel:
[] unchecked MSR access error: WRMSR to 0x1d9 (tried to write
0x00000000000001c0) at rIP: 0xffffffffaa070644 (native_write_msr+0x4/0x20)
[] Call Trace:
[] <TASK>
[] intel_pmu_enable_bts+0x5d/0x70
[] bts_event_add+0x77/0x90
[] event_sched_in.isra.135+0x99/0x1e0
Tested-by: Xiangfei Ma <xiangfeix...@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
---
target/i386/cpu.h | 6 ++++--
target/i386/kvm/kvm.c | 4 ++++
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 82004b65b944..8a83d0995c66 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -434,8 +434,10 @@ typedef enum X86Seg {
#define MSR_IA32_MISC_ENABLE 0x1a0
/* Indicates good rep/movs microcode on some processors: */
-#define MSR_IA32_MISC_ENABLE_DEFAULT 1
-#define MSR_IA32_MISC_ENABLE_MWAIT (1ULL << 18)
+#define MSR_IA32_MISC_ENABLE_DEFAULT 1
+#define MSR_IA32_MISC_ENABLE_BTS_UNAVAIL (1ULL << 11)
+#define MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL (1ULL << 12)
+#define MSR_IA32_MISC_ENABLE_MWAIT (1ULL << 18)
#define MSR_MTRRphysBase(reg) (0x200 + 2 * (reg))
#define MSR_MTRRphysMask(reg) (0x200 + 2 * (reg) + 1)
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index f148a6d52fa4..002e0520dd76 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -2180,6 +2180,10 @@ void kvm_arch_reset_vcpu(X86CPU *cpu)
{
CPUX86State *env = &cpu->env;
+ /* Disable BTS feature which is unsupported on KVM */
+ env->msr_ia32_misc_enable |= MSR_IA32_MISC_ENABLE_BTS_UNAVAIL;
+ env->msr_ia32_misc_enable |= MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL;
+
env->xcr0 = 1;
if (kvm_irqchip_in_kernel()) {
env->mp_state = cpu_is_bsp(cpu) ? KVM_MP_STATE_RUNNABLE :
--
2.25.1
