On 1/9/2023 3:28 pm, Xiong Zhang wrote:
With Arch PMU v5, CPUID.0AH.ECX is a bit mask which enumerates the
supported Fixed Counters. If bit 'i' is set, it implies that Fixed
Counter 'i' is supported.
This commit adds CPUID.0AH.ECX emulation for vPMU version 5, KVM
supports Fixed Counter enumeration starting from 0 by default,
user can modify it through SET_CPUID2 ioctl.
Signed-off-by: Xiong Zhang <xiong.y.zhang@xxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 95dc5e8847e0..2bffed010c9e 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1028,7 +1028,10 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
entry->eax = eax.full;
entry->ebx = kvm_pmu_cap.events_mask;
- entry->ecx = 0;
+ if (kvm_pmu_cap.version < 5)
+ entry->ecx = 0;
+ else
+ entry->ecx = (1ULL << kvm_pmu_cap.num_counters_fixed) - 1;
If there are partial fixed counters on the host (e.g. L1 host for L2 VM) that
are filtered out,
L1 KVM should not expose unsupported fixed counters in this way.
entry->edx = edx.full;
break;
}
